They don't call you honest John for no reason do they.
I write for the audience that reads it. But point taken, Max Power and the like still have very high circulation, wouldn't mind working for anything like that.
I don't have blinkers on, but am also the first to admit that my knowledge of journalism is lacking. There was a post on here referring to some freelance stuff and the ways and means of persuing that.
But like I said before, I'd work on a local rag for so/so money, as long as I get to write stuff and gain experience.
Thanks for your comments John.
Turbulent Tim.
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Tim,
Have had a look at the site, you're proud of that Cavalier! No need to worry about it being mistaken for a Xantia (my own area of interest). Actually look at the first couple of feet of the Calibra and early Xantia fronts....nearly the same.
Good advice from all the posts but remember most of us are hard bitten old gits. We wouldn't have given Chris Evans a chance of making it in the media either!
My humble advice would also be to get writing, slightly outside of your absolute main interest. In fact, a bit like a set test, get someone to set motoring topics and do 5000 words on them. Developing a style or two would be good as mentioned.
You are lucky to be thinking of this in the age of the PC, you have a home publishing system that would have been well thought of in commercial circles not too long ago.
Best of luck with it,
David
PS Keep posting to the Forum, a sane-ish "max power" guy might contribute to the mix!
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Max Power sounds like a good suggestion. Well done with the web-site if its your first. Nice pictures. Glad to see you are enjoying your car. Looks like the previous owner spent a fortune on it- what did you pay?
However, Tim i think you need to get your facts right before you start writing. It looks like you have been reading max power too much. The parts hanging bit on your page is a bit pointless. You cant just say this bit gives this much power and then add them up- the amount of power each modification gives depends on the state of tune of the engine, figure like that should only be used as a very general guide. A decent cylinder head should give more than 8% more power. The cylinder head makes more difference than anything else. Why is the 2.oltr XE so good? It overated, and does not have a particularly high power potential. An Mi16 engine offers far more power potential. The XE engine even has smaller inlet valves than VAG 16v engine from the mk.2 golf.
30bhp transmission loss is not likely unless your engine is producing 205bhp flywheel. Transmission losses are 15% for front wheel drive cars. You say your car may have 170 ft/lb of torque. This is very unlikely. Thats 85 ft/lb per litre- thats a figure one would expect from a full race engine. Go to a good rolling road and see how much power the car produces at the wheels, then you can work out more accurate guesstimate figures for power and torque.
The bit on top speed is completely wrong. Top speed is nearly all to do with peak bhp. The weight of the vehicle makes very little differnce.
BTW what is the heat protection- surely you have just removed the sound damping material. Also, it sounds a bit odd that the previous owner had the head rebuilt and fitted a new cam, but didnt change the lifters?
Ben
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Ok.. here we go:
I for one do not hold any faith or interest in Max Power stats, they are frequently exagerated to say the least and i don't wish to be labelled a Max Power person since it's not high on my list of car mags.
What's wrong with making educated guesses about an engine? My engine was rebuilt and is currently on 16k. Omega pistons, cosworth con rods etc etc all make the engine stronger. The head being ported and polished is no doubt better than the GM heads but perhaps not quite as robust as the Coscast breed. However, over-estimating on one thing and underestimating on another allow a certain level of inaccuracy when quoting power gains. The figures used were based on the experience of people who know their Vauxhalls well and have had similar experience with upping power/driveability.
170lbft is optimistic, I estimate 160lb/ft or a touch under, point conceeded.
The XE engine is a very good engine. 150bhp or 156bhp without a CAT as standard. Astra GTE 16v pulling mid 7's to 60, 135mph top end easy. Forget the 'indifferent' handling, thats a fast car. Fast to the point that it can embarrass most of the stuff rolling off production lines everywhere,within reason.
An astra owner who has invested much time and money in an XE engine has performance that beats many 'supercars' and has been proven many times over.
0-60 - 5.5, 156mph or so top whack, mid 13s 1/4 mile. Thats running about 220bhp at the flywheel after removing the restrictive standard induction and adding throttle bodies. Yeah it's an astra, but that's not the point in question.
the standard cav Gsi will do 135mph as standard, since it goes way off the clock. Taking into account speedo inaccuracies, should the dials allow it you would see 145mph. A 30bhp increase could easily give at least 5mph top end. Since it has more power to deal with the drag at higher speeds.
The heat shielding/sound protection was removed to incorporate the strut brace as the bonnet would not close with it on. It allows slightly more air to circulate too which is healthy for the induction kit.
The lifters ran fine when the last owner had the car, for 1000's or miles after the rebuild. Vauxhall hydraulic lifters can take up to 250bhp or 250lb/ft as standard and since my car doesn't make that level of power or torque, should be no problem. However show me an XE engine that doesn't rattle on startup or require some new lifters at some point during it's life? If they have been in there 10 years, I think that's a fair stint for such an over-rated engine.
The pug, Mi-16. What is so special about this engine? I came up against a 205 fitted with that engine when I had my mildy modded nova GTE. I matched it on acceleration and would only expect to lose to that at licence losing speeds.
Stuck in a heavier car that doesnt impress me much at all.
Standard spec as I read it for the 2.0 Mi-16,
Peugeot 405 Mi-16 0-60 9.8 seconds, top whack 133mph.
Cavalier Gsi 0-60 8.5 seconds, top whack 136mph.
The cavalier is 120kg heavier too on kerb weight.
Mi-16 - 155bhp --> 139bhp per tonne
GSi - 150bhp --> 134bhp per tonne
Exactly how much would you need to up the power on this wonder -engine in a 405 to match even a bog standard GSi? 9.8 seconds to 60 is poor. No 16v engine picks up particularly quickly but this is still far from impressive, and with 133mph top end seems it's not amazing a top speed either.
The older 1.9 Mi-16 is better. 160bhp, 0-60 in 8 seconds, 153bhp per tonne, 132mph top speed. But still not much better acceleration than a standard Cav Gsi and down by 3-4mph top end too, also noticeably slower than a 16v GTE.
What is it that makes this engine so good? I know little about it, so it's an honest question. It's still 4 cylinder, 210 kgs lighter than the GSi!! Owners say it's gutless below 4000rpm, but quicker if you cane it to 7000rpm constantly. So in some respects it's similar to the cavalier. However I maintain a good 16v GTE would beat it with little trouble.
How can u say bodyweight makes very little difference? Top speed perhaps it doesnt matter as much as bhp but it might make a difference as to how fast the car gets there. If a Cav Gsi was the same weight as the GTE 16v it would match it's performance. My car is roughly 20% more powerful than a standard GTE 16v, making up the 20% weight difference and so can match it on acceleration, perhaps beat it top end.
Over to you.
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I was talking to my local tuning place and amongst other things they said that extracting power from the Pug engines was not as easy as people claim. They also said the same about the Vaux 8v engines, but did say that the Vaux 16v engines always made the book power.
Top speed will be roughly governed by drag factor, car frontal area, power at wheels and correct gearing. Weight will not affect top speed ,except to a small degree due to rolling resistance increases.
Weight will obviously factor directly into acceleration.
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15% is not some magic number created by God to be applied to all fwd drive cars! My car lost 31.5BHP throught the transmission when it made 132BHP and now loses 31.5BHP when it's making 142BHP. That's about 24% and 21% respectively. I would suggest that for a particular gearbox, the losses at a certain speed consists of a near constant part plus a load dependant part, so losses will increase slightly as the BHP through the box is increased. The F16 box fitted to a lot of early 90s Vauxhalls seems to lose about 32BHP, the F20 box fitted to cars like Tims seem to lose a bit more.
You can make a very rough estimate as to expected power by multiplying a string of percentage increases for mods together. It will be very approximate since the interaction of the various parts will affect the results. But, an 8-10% increase in torque and power is realistic for a good head, the standard 16v head is good to start with, ask Bill Blydenstein about it.
When you say "good cylinder head", I suspect you mean more than just a modified head. Maybe you mean with larger valves, back cut valves, raised compression ratio etc? I wouldn't expect a modified head alone to give much more than about a 10% change.
The 20XE engine is rated highly because it starts life in a relatively high state of tune, and can easily make 170BHP sort of region without major internal modifications. It can make 200BHP region with internal modifications, and more if running at higher revs. It is highly rate because a few years ago it was possibly one of the cheapest ways of creating decent power from a sturdy and reliable and common unit.
Inlet valve size is no performance indicator. The MK2 Golf 16v engine was not liked because of its poor mid range torque. The 20XE engine was praised for its full range performance. This was due in part to the carefully tuned induction system, the torque curve is a masterpiece.
170lb-ft is a little high, but 160lb-ft would not be out of the question. Assuming that a 10% torque increase is feasible then that should achieve something like 160lb-ft from the standard 149lb-ft. Need to check with someone like SBD as to what sort of torque figures their kits make.
Talking about torque figures and race tuned engines, a race tuned engine will tend to be tuned for very skilled driving in a narrow rev range. This tends to mean tuning for high BHP at high revs, as a result, the torque figures will not be astounding. Depends on the tune obviosuly.
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What a load of rubbish. VW technical say there cars loose 15% through transmission loss. Bosch chassis dyno division say 15%. 24% transission loss is rediculous. If you lost that much it would be like having a 25kw heater for a gearbox- the oil would probably boil. These guys are just manipulating the road and software to show whatever figures they like. I have seen it done. I know people who run rolling roads, and they always tell boy racers there cars make much more power than hey actually do.
Some losses throught the gearbox remain constant. Most dont. 15% is a good guide.
I was talking about standard valve size cylinder heads.
Inlet valve size is no performance indicator. Hmm. Inlet valve area is the single most important factor in determining engine power. If you cant get loads of air into the engine you cant make any power. Engines burn air and fuel to make power. Supplying the fuel isnt difficult.
Early mk2 golf engines (16v) behave differently to late models due to the change of inlet manifold. Autocar managed 7.1sec out of a 16v Jetta, and 7.3 from a 16v golf. Later cars tested by other magasines only manage around 8 secs.
"This tends to mean tuning for high BHP at high revs, as a result, the torque figures will not be astounding. Depends on the tune obviosuly." Torque cannot be easily increased. There is only so much air you can get in a cylinder in one stroke. Power is torque times horsepower. So to make big power you need torque at high rpm. Its really quite simple.
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> What a load of rubbish. VW technical say there cars loose 15%
> through transmission loss. Bosch chassis dyno division say
> 15%. 24% transission loss is rediculous.
A gearbox contains rotating elements on bearing surfaces with lubricating oil. Losses are primarily due to friction of the bearings, torque loss is due to overcoming the viscous friction. You can change the losses by changing the design. Therefore 15% is not a fixed constant, it might be a very good approximation for certain gearboxes, but there is no reason why some lose 14% and others 21.42% and others 22.32%. Different oils will make a few percent difference as well.
>If you lost that
> much it would be like having a 25kw heater for a gearbox- the
> oil would probably boil.
I lose 31.5BHP in the transmission system at max engine speed. That's the cumulative total of gearbox, differential and tyre losses. I have numerous rolling road printouts from various testers with my engine in various states of tune and they all show between 30 and 32BHP loss for my gearbox for flywheel powers between 132 and 142BHP.
I know people who run rolling roads, and they
> always tell boy racers there cars make much more power than
> hey actually do.
I know that this goes on as well. All my measurements have been done on back calculating rolling roads that work out the transmission losses on the run down. And the figures stack up because a magazine article I have states that the 8v Astra GTE makes 100BHP at the wheels, for 125-130BHP at the flywheel.
> I was talking about standard valve size cylinder heads.
> Inlet valve size is no performance indicator. Hmm. Inlet
> valve area is the single most important factor in determining
> engine power.
I quote from "modern engine tuning" by A Graham Bell, page 21
"many tuners by habit replace the stock valves with oversize items....
However, many engines already have sufficiently large valves for road applications".
If inlet valve area was the single most important factor then that's what all tuners would concentrate on. Most tuners are trying to increase the volumetric efficiency of the engine and they rightly realise that the induction system has a large part to play in this. Yes the inlet valves can restrict past a certain point. And cam lift and duration also play their part.
>If you cant get loads of air into the engine
> you cant make any power.
You can't make "any" power. You can make power in proportion to the air flow you can achieve and the quality of combustion and a few other things like compression ratio etc
> Early mk2 golf engines (16v) behave differently to late
> models due to the change of inlet manifold. Autocar managed
> 7.1sec out of a 16v Jetta, and 7.3 from a 16v golf. Later
> cars tested by other magasines only manage around 8 secs.
I don't know what years they changed. I saw an article from What Car 1988 where they didn't like the VW torque characteristics.
>Torque cannot be easily increased. There
> is only so much air you can get in a cylinder in one stroke.
Agreed. Volumetric efficiency increases of about 20% are possible, torque cannot be increase easily that much beyond here.
> Power is torque times horsepower. So to make big power you
> need torque at high rpm. Its really quite simple.
You've used the wrong words, but I assume that's a typing mistake. Power is torque multiplied by speed, yes. So make torque at higher rpm, that gives more power.
That's what mean effective pressure is useful. ie: power to air flow ratio,
power / (rpm * cc of engine).
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"it might be a very good approximation for certain gearboxes, but there is no reason why some lose 14% and others 21.42% and others 22.32%." While i do not believe transmission losses in fornt wheel drive cars will be that high, would you care to explain how on your car, with the same gearbox, the percentage loss through the transmission changed- did you put sand in the gearbox? My knackered antedeluvian 16v Jetta makes around 146bhp flywheel, thats 124bhp at the wheels. Thats what i think, the guy that tuned it thinks, and the engine builder that builds Paul Rose's winning Slick 50 race car thinks. Are we all wrong. The only way to tell the actual loss is to measure the engine on a dyno, and then measure it on a chassis dyno and take one from the other. Coast-down losses are a joke. When you next go to the "expert" at the rolling road, get him to run the car in third , fourth, and fifth gears, and measure the coast-down loss. Now these figures should all be the same. I bet they are not. If you can loose 24% through the transmission where does all this energy go?
I said inlet valve area. that doesnt just mean the valve. when you fit bigger valves you port the head. The cylinder head represents the biggest flow restriction on nearly all engines. Yes cam lift and duration play a part, but there is no point increasing lift if you are already achieving max flow for that port (NOT valve). So sticking high lift cams in a standard head can have a significantly smaller affect on power output than fitting them to a properly ported head.
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21% is rubbish ?? I get 33% loss on mine. Yes thats right -
Cavalier Turbo (4WD) - 204BHP@flywheel and 133BHP@wheels
Thats a whopping 1/3 loss
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Er you were a bit more emphatic than that! I quote what you said...
>What a load of rubbish. VW technical say there cars loose 15% through >transmission loss. Bosch chassis dyno division say 15%. 24% transission loss >is rediculous.
>If you lost that much it would be like having a 25kw heater for a gearbox- the >oil would probably boil.
I lose 32BHP at max speed, that's about 24KW yes.
But your argument would still apply if it was 15%. That'd be like have a 15/24*25= 16KW heater for a gearbox. The oil does not boil then either. Thing is, those losses are a combination of gearbox and wheel bearings and tyre losses. It does go as heat, but not all into the oil in the gearbox. Plus, the heat that does go in is transferred away through the metal of the housing into the engine coolant and also convects into the air from the surfaces.
Nextly...
>would you care to explain how on your car, with the same gearbox, the >percentage loss through the transmission changed- did you put sand in the >gearbox?
The amount of power that a gearbox loses will vary with running speed, power transmitted and gear selected. It would appear that the gearbox I have loses very roughly speaking the same amount of power when I was putting 132BHP through it as when I was putting 142through it. That's a 8% increase in power going through it. I'd expect the losses to have increased very slightly, but that's lost in the measurement error, different tyre pressures on different tests etc. The point I've been trying to make is that 15% is a rought estimate, it's not an absolute physical constant created by God. So in my case the losses were about 24% and 22%. This might seem high, but I believe the figures because the spec for the car is 100BHP at wheels for 125-130BHP at flywheel, so between 25 and 30BHP is lost. Maybe I could reduce this loss, or maybe the Vaux boxes are a bit more lossy than they could be.
>Coast-down losses are a joke.
No they're not, they measure exactly what you want to know which is the total losses for the transmission. I would say though that 2-3% accuracy is all I'd expect from a dyno anyway.
>When you next go to the "expert" at the rolling road, get him to run the car in >third , fourth, and fifth gears, and measure the coast-down loss. Now these >figures should all be the same. I bet they are not.
I wouldn't expect them to be the same either because the losses will differ for different gears.
>If you can loose 24% through the transmission where does all this energy go?
These losses go to the same place as the 15% you lose on your Jetta. ie: heat mainly.
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Coast down losses are a joke. you are right differnt gear will give you differnt power at the wheels, but add the coast down losses ontot hese figures that you get in each gear, and you will end up with three different answers! The gearbox it self actually only looses around 5%. If there is so much heat created in the gearbox why does mine take so long to warm up. Gear-change on my banger is poor till the oil thins out which can take 20 mins.
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You don't drive at max revs all the time is why. Plus not all of the losses are in the gearbox, some is at the tyres which noticeably warm up. The heat is dissipated into the metal of the gearbox and engine, so it is cooled by the engine cooling system.
I've never tried the different gears on a dyno, but I believe that you will get different answers. How much will they vary by typically though? If its less than 5% then I'd live with that. The wheel dyno shouldn't really be used as an absolute power measuring device, more as a diagnostic and back to back check. I went to three rolling roads in a short period of time and got three different results, two of which I believe.
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Where in your post did you mention FWD ?? Mebbe I am going blind. This is the 2nd time you have "moved the goalposts" in your arguments.
1st - Oh, we are now talking about the 1.8 16v and not the 20XE (2.0 16v)
2nd - Now we are talking about FWD only and not 4WD as well ??
Whats goin on here ??
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"Transmission losses are 15% for front wheel drive cars." I cut and pasted this from my first post. This is what VW have told me. I could may well be wrong. I am not saying you dont have a good car or anything like that. I expect 4WD losses are far higher than 15%- you know far more about this than me. I wish i could afford a 4wd car- enjoy it!
Ben
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"150 ft/lb is the limit from the VAG 16v engine, and thats with bigger valves. " This is a direct quote from what i have posted on this board. However, i should have clarified this by stating that i was talking about the 1781cc KR engine.
Ben
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and i get a whopping 25% loss through my F20 gearbox, 119 at the wheels 158 at fly, is my local rolling road talking pish as well ? i did remember to take out my max towel sticker that day so they cant have been discriminating that day
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i have a 2wd astra 16v before you say anything derogatory
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If it makes 133bhp with 33% lost through the transmission that means you have 198.5bhp. (133/0.67)
Ben
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OK he means 34.8039%, but that level of precision is meaningless. I wouldn't expect a dyne to be better than +/-2% on accuracy, so what's the difference between 204BHP and 198BHP? Nadge all.
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Take a look at this graph from SBD developments, showing a 20XE engine making 170lb-ft. "all this is achieved without opening the engine to modify in any way , except to change the standard conrod bolts to heavy-duty bolts".
www.sbdev.co.uk/Taper%20Throttle%20Kits%20for%202....n Chapman wrote:
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Blah blah blah. I cant be bothered to put it all straight but that grapgh is dodgy. If you plot bhp against torque measured of ft/lb the curves MUST cross at 5250rpm. 85ft/lb per litre means the iar pressure in the cylinder head is already way over atmospheric pressure. You wont get anything more than this without pulse tuning.
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Power in BHP = torque in lb-ft x speed in thousands of rpm * 0.193
So yes, at 5.25 K rpm 1 lb-ft = 1 BHP.
That graph might be dodgy, but the above wouldn't show that. It might be incorrect data. But I posted it to show that torque gains close to what Tim was claiming/hoping for are possible with the 20XE engine.
>85ft/lb per litre means the iar pressure in the cylinder head is already way >over atmospheric pressure.
The air pressure in the cylinder head is going to be way over atmospheric due to combustion. That's the idea of the engine!
Oh, you mean on induction? I think the volumetric efficiency method makes it clearer. A normal engine will be 70-75% volumetrically efficient. Tuning might increase this to 80-85% say. This does imply an increase in the air pressure on the induction stroke, but not a massive on, say about 15%. Because 15% more charge will mean 15% more torque roughly speaking. The inlet air pressure will normally be below atmospheric pressure do to losses in the induction system, valves etc. So after tuning it will still be below atmospheric pressure, but less so. If it was above atmospheric pressure then air wouldn't flow into the cylinder.
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So you admit the graph is not possible.
When i say air pressure is over atmospheric i am talking about the pressure the air is entering the cylinder head. The amount of air that enters the cylinder head detemines how much fuel you can burn, and hence power generated by that stroke.
." A normal engine will be 70-75% volumetrically efficient. Tuning might increase this to 80-85% say. " these figures show you do not understand what you are talking about. My engine even in its present poor state of tune has peak volumetric efficiency of over 100%- 132ft/lb @5krpm (ie 107bhp@wheels@5k rpm). 150 ft/lb is the limit from the VAG 16v engine, and thats with bigger valves. You are talking rubbish. Tuned engines can achieve up to 130% with pulse tuning. Try looking up Pulse tuning on the internet or something- you might start to understand what you are talking about then.
Ben
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This torque limit seems a little strange. I've got a C20XE (vauxhall 2.0 16V) engine on throttlebodies. When it was running standard induction, and was unmodded, i had it rolling roaded, (Well Lane Turbo Centre) it made 161 BHP @ 6500 and 155ft/lb of torque at 5500rpm. Surely a well tuned VW engine would be able to achieve this.
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I was talking about the 16v 1781cc VAG engine. This engine can make 230bhp maximum in 1800 and 2ltr forms. 150 ft.lb was the figure for the 1800. the 2ltr engine does offer a torque advantage.
Ben
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Ben I do know what I am talking about. I suggest that maybe the reverse of your statement would be closer to the truth. I quote from page 54 of "Internal Combustion Engine Fundamentals" by John B Heywood (ISBN 0-07-100499-8)
"typical maximum values for volumetric efficiency for naturally aspirated engines are in the range 80 to 90 percent".
Air enters the cylinder head below atmospheric pressure! It is sucked in, not pushed. By definition it will be lower pressure, since it is the pressure differential that causes the air to flow in to the chambers.
What is your definition of volumetric efficiency? I use the industry standard, ie
2 x actual air mas flow rate divided by cc x rpm x air density.
Please explain the reasoning for calculating your volumetric efficiency.
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Typical max values for road cars yes. But im talking about tuned engines- engines that have some degree of PULSE TUNING, where air is inducted above atmospheric pressure due to the pressure waves that exist in the inlet and exhaust. The resonant frequency of these waves is realtive to the mass of air the systems contain. A vauxhall example would be the use of a dual ram inlet on the Carlton GSi 24v. If you dont think it ames a difference disconnect it, its easy. the Carlton has two peaks in the torque curve becasue of this system.
To get a rough approximation of VE i usually multiply the torque per litre by 1.4.
Ben
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Yes I agree induction tuning can increase volumetric efficiency due to gas momentum "pushing" more air into the cylinders. Indeed, the 20XE engine has such a fat torque curve because Cosworth/Vauxhall spent time tuning the induction system.
Your rough method of estimating vol effic, I try it on my 2L 8v Vaux engine (20 SER, Sri 130 engine). I was making 129 lb-ft, so I get
vol eff = 129/2*1.4=90% seems too high to me,
After fitting a B+ head I'm making 139lb-ft, so now
vol eff = 139/2*1.4 =97%, seems too high.
I agree that torque per litre should give an estimate of vol efficiency because it represents the charge fill efficiency.
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Tom stick you kick asss m8.LOL
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I've just done some first principle sums, and the result I get is:
approximate volumetric efficiency = Torque (lb-ft)/cc(litres) * 1.15
thats using an indicated efficieny of 45%, mechanical efficiency at max torque speed of 0.9, a 14:1 air fuel ratio, air at standard temp and pressure, fuel calorific value of 43MJ/Kg. The thing is, that magic 1.15 number contains assumptions about other engine efficiencies.
So take my 2L 8v, making 129 lb-ft, I get
approx vol eff = 129/2*1.15= 75%
Making 139 lb-ft I get
approx vol eff = 139/2*1.15=80%
sounds realistic to me, maybe a tad low.
Now consider the 16v engine making 150lb-ft
vol eff = 86%
Now making 165 lb-ft
vol eff = 94%.
Hm, 165 lb-ft does seem a bit too high. Say that the magic 90% has been reached, then max torque would be around 157 lb-ft point. But there's a lot of assumptions in the maths, so 160 lb-ft would seem plausible.
Another thing: I do not agree that the graph is incorrect or wrong. The torque curve is plotted direct and I assume that SBD developments have measured that correctly. Plus they carefully tune their throttle body kits for the induction ram effect, so they might be pushin the vol efficiency that bit higher.
Finally: It is not necessary to reduce the discussion to a personal level re: "you are a max power reader" and "you don't know what you're talking about".
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Sorry i should not have made personal comments like that. Thank you for the lively discussion. Anyway, i think you should read the following web-site: www.pumaracing.co.uk ,in particular the bit on coast down losses i think he agrees with and explained what i have observed. Maybe you would like to disagree with him and invite him to post on this forum. This guy builds wonderful engines. If you dont believe anything i say, maybe you will believe him. The fact is that when the flag drops the bullshit stops. This guy has won just aobut every series he has entered with one of his engines. Just look at his slick 50 success. This guy can tune Mi16 engines to produce 300 bhp- thats from a 1905cc capacity. That is what i call a good performance engine.
Ben
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Hey no problem Ben. What I do know about engines and tuning I'm confident with, but there's loads of stuff I don't know about. So lively debate is fine by me, it's a good test of ideas etc. I tend to like to test out things myself, so next time I'm down the dyno I'm going to get coast down results in a few gears and see how the calculated torque curve varies.
My local place said to me "don't worry about the peak BHP, there's more to it than that". And I tend to agree with them to an extent - some engines pull really nicely in a way that dyno data alone can't explain.
Engine tuning is an involving and difficult area. Which is why it's so interesting I suppose. But the boy racer mags with their fairy land BHP claims always make reality seem a let down. My car makes 142 BHP, up from about 129 when I bought it. Doesn't sound like much, but it's a total blast on the road, it feels much faster than it should.
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SBD can tune the vauxhall X16XE (1.6 16v) ecotec engine to 235bhp, peak torque is 150lbs and it would be an insult to call it a torque curve cause it looks like its been drawn with a ruler. rises to 130lbs at 5000rpm and goes striaght off the chart past 9500rpm. Thats what I call a race engine.
www.sbdev.co.uk/Taper%20Throttle%20Kits%20for%201....f
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Ben, mebbe you should take a look at a few RR results as 150 lb/ft is NOT the limit of this engine.
Try this page for starters - www.16vastra.co.uk/rolling_road_day.htm
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