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

[carl_w]

TVR AJP8 4.2 599
TVR AJP8 4.5 654
TVR AJP6 4.0 653

[leafspring]

Wait I can beat the low score record

2286cc DIESEL Land Rover from 1960

90.49mm bore (same engine block as the petrol ), 4 cyl, 62hp = 195

[KM666]

Astra G 1.8 sport (x18xe1)

Bore 80.5
Cyl 4
Bhp (claimed) 115

PI 458

But its got a derestricted airbox and K&N element so probably more like 150bhp, 170bhp when the stickers are taken into account. Making it a rather more respectable 677.

[Kozy]

leafspring said:

Wait I can beat the low score record

2286cc DIESEL Land Rover from 1960

90.49mm bore (same engine block as the petrol ), 4 cyl, 62hp = 195

I'm not sure we can count diesels unfortunately, but that really is comically low.

[Major Fallout]

114 for the speedster :-( But it's developing twice as much power as stock haha

360 ish for the tvr.

547 for the bmw

680 for the Lola

And about 800 for the lotus engines in the racing cars. :-)

I'm happy with that, I will need to change the head for over head valves to get over 120 in the speedster really. To double the power again I would have to spend about 6-7k. Something to do later on in life.

[Kozy]

Major Fallout said:

114 for the speedster :-( But it's developing twice as much power as stock haha


I'm happy with that, I will need to change the head for over head valves to get over 120 in the speedster really. To double the power again I would have to spend about 6-7k. Something to do later on in life.

Well that puts paid to my theory about low PI engines being cheap to get more power from!

[JordanTurbo]

My C5 shape Audi S6 scores a respectable 605

84.5mm bore
8 cylinders
335 bhp

Edited by JordanTurbo on Saturday 12th October 23:48

[Huff]

R1 5PW engine in my Fury: 74mm bore, 165hp from 998cc = score of 777.

[leafspring]

1.0 Citroen AX Dimension = 263

1.4 Renault 5 Campus Prima = 270

[ezi]

2.0 Duratec Fiesta ST
Bore 87.5
Cylinders 4
Power 190

Score: 637

[Dodsy]

Ok so not 4 cylinders but I checked my old and new jags

XJ8 - 86mm bore 8 cylinders na 300bhp , PI 523 should be capable of 574bhp
XJR - 86mm bore 8 cylinders supercharged 400bhp PI 697 also capable of 574bhp

Edited by Dodsy on Sunday 13th October 00:06

[XJ Flyer]

I think the important thing is getting the combination and ratio of bore and stroke measurements right and the resulting compromise between good top end power and low down torque not just concentrating on specific power outputs.Remembering that the stroke measurement doesn't just add to the engine capacity it also adds to the leverage of the piston on the crank and it's torque that makes acceleration not top end power.While in many real world examples the increase in torque also provides around the same or even more specific power at the top end.Such as in the case of the Jaguar XJRS 6.0 Litre engine which produced around the same specific top end power with a lower compression ratio compared to the old 5.3 HE with the advantage that it's produced at lower engine speed.

[AW111]

4AGE blacktop (Toyota)
81mm bore (77 mm stroke)
162 bhp

PI = 637

[AW111]

KM666 said:

Astra G 1.8 sport (x18xe1)
BHP (claimed) 115
...
But its got a derestricted airbox and K&N element so probably more like 150bhp, 170bhp when the stickers are taken into account
...

That made me laugh.

One day I will release my "sticker dyno". You enter the number and size of the performance stickers on the car, and the number of rear wing elements, and it tells you how much power the owner thinks they have.

Edited by AW111 on Sunday 13th October 02:05

[DanielSan]

S2000 is already answered in the OP, so of the road cars so far I shall just merely claim a smug victory

[Rick 343]

I got 836 for the E46 M3 not 811?

ETA just noticed your on us spec with 333bhp

[dvs_dave]

carl_w said:

TVR AJP8 4.2 599
TVR AJP8 4.5 654
TVR AJP6 4.0 653

If we're using factory quoted numbers (as everyone else is) then the TVR Speed Six 4.0 S spec PI is 756. If it were tuned to F1 levels then 536hp is your lot.

For a popular comparison, a Chevy LS3 crate PI is 520

Edited by dvs_dave on Sunday 13th October 06:06

Edited by dvs_dave on Sunday 13th October 06:17

[DJP]

Volvo V70 - 5 cylinders, 83mm bore, 2435cc, 140bhp = 419

Bandit 1250 - 4 cylinders, 79mm bore, 1255cc, 100bhp = 413

Both lazy lumps, but it seems counter-intuitive that the bike, with 71% of the power from 51% of the capacity, should be in a lower state of tune than the car engine.

[anonymous-user]

Alpina B3 3.3

Bore 86.4
Cylinders 6
Power 280

PIes 645

[Escy]

Porsche 968 - Bore 104, 4 cylinders, power 236bhp = PI 563
Porsche Boxster 2.5 - Bore 85.5, 6 cylinders, power 201bhp = PI 473


I've never owned a Porsche, I tend to buy cars based on engines and Porsche make nothing decent anywhere near my budget. I don't know how Porsche get away with selling such rubbish as sports cars. No wonder they are perceived as reliable with the power they produce. Maybe they used the blueprints from the 2.2 Land Rover engine posted earlier?!