For the 'natural aspirators' - How tuned is your engine?

[otolith]

Scuffers said:

Kozy said:

So you don't believe that BAC or Caterham are actually making the figures they are claiming?.

Basically, no.

These things aren't typically independently dyno'd, and certainly not with the engine out of the car, but they are usually independently figured - are the independent acceleration tests, verified weights and claimed power figures inconsistent?

[stevesingo]

Scuffers said:

Basically, no.

As the BAC uses a Cosworth crate engine, I would say that the calimes are more likely to be true than false.

http://cosworth.com/media/335568/duratec_component...

280hp and 201lb/ft, 121hp/87.5lbft/litre is not beyond the realms of possiblity.

[Scuffers]

not suggesting it's not possible for a 2.3 duratec to make 280, just that in that install, has it actually been accurately tested as such?

same deal with the atom figures, caterham r500 (k series), etc.

[stevesingo]

Given the industry standard for power rating engines is on a an engine dyno, I don't think it would make much difference as to what it is installed in.

If cosworth rate this engine as 280hp on the engine dyno, what makes you think this is any different to Lotus rating their Toyota engines, or TVR rating their RV8s or AJ engines.

[nsa]

Kozy, would it be worthwhile having Car, engine, cyl, bore, power, PI on the left side of the Wiki to make it easier to update?

[Greg_D]

my kart engine is 1598 - beat that

53.9
1
45

you could argue that the 'true' figure is half that because it is a 2 stroke but the bottom line is it is 360bhp/litre NA so incredibly powerful for it's swept volume and that is what matters...

[Scuffers]

stevesingo said:

Given the industry standard for power rating engines is on a an engine dyno, I don't think it would make much difference as to what it is installed in.

If cosworth rate this engine as 280hp on the engine dyno, what makes you think this is any different to Lotus rating their Toyota engines, or TVR rating their RV8s or AJ engines.

yes and no.

industry (as in mainstream OEM's) will have to test their engines to death both in car and on engine dyno's, however, even when on the engine dyno, they will have to replicate the install of the car, ie, same exhaust, intake, etc etc. otherwise any calibration work that's done becomes void when it's put back in the car.

Now, I am sure that at some point, Cosworth will have dynoed a 2.3 with all their parts on it and made 280Hp, BUT, once they sell a crate engine to a customer, that then installs it into their car with ?? intake/exhaust/fuel system, ?? ECU, and ?? calibration, I bet it never see's the light of a calibrated engine dyno cell ever again.

[XJ Flyer]

stevesingo said:

Kozy said:

One thing I am interested in is the costs of tuning various engines. If anyone posting here has actually tuned their engine, an interesting one to know would be the before and after PI score and the cost to upgrade!

2467cc BMW S14 238hp as standard PI=680

Pistons £750
Head work £1000
Cams £800
Airbox £1200
Exhaust £600
EMS I spent £3000, but you can get away with £1500

TOTAL £5850

Result is 280 hp on the Dyno PI=800

800-680=120
5850/120=
£48.75 per PI

Ouch

It's still probably good old fashioned American V8's which provide the most cost effective way to get horse power in the real world.

www.jegs.com/p/Blueprint-Engines-Small-Block-Chevy...

[stevesingo]

6.5 litre and only 485hp-500lb/ft.

Not very efficient is it!

[XJ Flyer]

stevesingo said:

6.5 litre and only 485hp-500lb/ft.

Not very efficient is it!

It depends on the definition of 'efficiency'.IE an expensive screamer or relatively low revving,so long lasting,affordable,torque monster.

[Kozy]

XJ Flyer said:

stevesingo said:

6.5 litre and only 485hp-500lb/ft.

Not very efficient is it!

It depends on the definition of 'efficiency'.IE an expensive screamer or relatively low revving,so long lasting,affordable,torque monster.

Well I make that a 102.5mm bore which gives it PI of 595, which is pretty respectable to be honest.

[XJ Flyer]

Kozy said:

XJ Flyer said:

stevesingo said:

6.5 litre and only 485hp-500lb/ft.

Not very efficient is it!

It depends on the definition of 'efficiency'.IE an expensive screamer or relatively low revving,so long lasting,affordable,torque monster.

Well I make that a 102.5mm bore which gives it PI of 595, which is pretty respectable to be honest.

I'm not sure if the PI figure being referred to is just another way of saying the specific output based on bore dimension as I've described in the LS7 LS3 comparison ?.

If so the benefits of low down torque for acceleration and if engine speeds are going to be kept within reasonable levels for durability then probably it's all about getting the bore and stroke combination to,or as close to,the ideal of being square,as opposed to over square,as possible.

Edited by XJ Flyer on Monday 14th October 17:43

[cirian75]

Greg_D said:

my kart engine is 1598 - beat that

53.9
1
45

you could argue that the 'true' figure is half that because it is a 2 stroke but the bottom line is it is 360bhp/litre NA so incredibly powerful for it's swept volume and that is what matters...

any of the late 1990s early 2000s MotoGP v4 200bhp 500s 2 strokes will easy

[jones325i]

Caruso said:

My BMW 540 engine which is torquey rather than top endy scored 547

My Honda Superblackbird motorbike engine which is very top endy scored 566

Hmmmm...

The 550i also scored 547.

[AW111]

Kozy : could you add a column to the wiki for theoretical max power, ie bhp x1000 / PI?

That would be the max power you could extract from that engine according to your formula.

Eg the Toyota 4age stands at 649 PI with 165 bhp, so theroretical max is 254 bhp.
These engines (16 valve version) were used in Formula Atlantic, and gave about 240 bhp in rev-limited form, which fits well with the "ultimate" power of 254.

In fact, any 81mm bore engine comes out at 254 hp max!

[Kozy]

AW111 said:

Kozy : could you add a column to the wiki for theoretical max power, ie bhp x1000 / PI?

That would be the max power you could extract from that engine according to your formula.

Eg the Toyota 4age stands at 649 PI with 165 bhp, so theroretical max is 254 bhp.
These engines (16 valve version) were used in Formula Atlantic, and gave about 240 bhp in rev-limited form, which fits well with the "ultimate" power of 254.

In fact, any 81mm bore engine comes out at 254 hp max!

Yep, that's what most stock bore Honda B series engines max out at too!

I think it's probably a bit too much info for the Wiki, but if people are interested a link to the article is there and they can look it up.

[Greg_D]

cirian75 said:

Greg_D said:

my kart engine is 1598 - beat that

53.9
1
45

you could argue that the 'true' figure is half that because it is a 2 stroke but the bottom line is it is 360bhp/litre NA so incredibly powerful for it's swept volume and that is what matters...

any of the late 1990s early 2000s MotoGP v4 200bhp 500s 2 strokes will easy

blimey, you have a late 90's MotoGP engine, crumbs......................thought not!!!

[Kozy]

I've been working on a version of this for boosted engines.

I'm not sure on it yet, because of the difference between peak boost pressures and boost pressures at peak power, but here it is regardless as a test page:

http://blackartdynamics.com/EngineLimitsFI/Index.p...

An example of what I mean is that the quoted figures for the FQ400 are 387lbft at 1.3bar, which gives it a PI of 645, but the boost at peak power might only be 1bar, which would give it a PI of 742.

Quite a wide range as yuo can see.

Which should be the more relevant boost figure to use? Perhaps an average of the two? That would give the FQ400 a MAP of 2.15bar and a PI of 690...

Edited by Kozy on Wednesday 23 October 13:09