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Conversation on FB about the performance that can be got from a 2.5L engine.    200bhp from flowing, raised compression, Pi and a 6-3-1 exhaust.    260 from a full race engine - steel crank, over boring, very high compression and revs, etc etc. 

What does the TRR think of such claims?

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Depends on who is doing the claiming John, and are they talking flywheel ? Trouble about Facebook are the numpties who post there, makes believing a leap of faith unless you know them. 6 cylinders not my forte and Neil ( Ntc) will have a good angle on these numbers. A current racer like Dave McDonald will also have good feedback on them.

Mick Richards

Edited by Motorsport Mickey
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30 minutes ago, tr7v8 said:

As a standard TR6 engine makes 150bhp another 50bhp from modifications hardly seems a wild claim.

With a steel bottom end, the higher rev limit will only raise this figure. 

No it does not. And never did that comment just fuels the nonsense as Mick said.

Edited by ntc
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I believe 260 bhp has been achieved - but not for long if you get my drift.

240 is a more realistic reliable figure from several full race engines, all built by several different specialists, with steel crank and rods, forged large bore pistons, special head gasket to suit, high compression, high lift cam, roller rockers, 6 - 3 - 1 exhaust, lightweight skeletal flywheel, gas flowed head and an ATI harmonic crank damper. Triple 45DCOE carbs. They will run to between 7200 - 7400 rpm but max power will be at around 6800 rpm. 

Dave McD

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250 is a figure that has been claimed from a number of reliable sources on a fully worked race engine. Longevity is probably not the concern of those that afford the goodies required!

Reasonably easy to get 180+ for a reliable and drivable road car. Beyond that drivability is starting to be compromised but PI is very forgiving allowing some wild cams to be set up to be drivable.  30 years ago I recall Chestnut House fitting their race cam into road cars with adjustments to cam timing. Drove well enough but fuel consumption of 16mpg!

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1 hour ago, alan57 said:

I seem to remember someone once saying "torque makes cars fast, power makes engine builders rich"!!!!

Horsepower is how fast you hit the tree, torque is how far you moved the tree.

Stuart.

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  • 4 weeks later...
  • 2 weeks later...
On 9/16/2021 at 4:02 PM, alan57 said:

I seem to remember someone once saying "torque makes cars fast, power makes engine builders rich"!!!!

I am sure i had the same person say to me ,  torque wins races ,   BHP sells engines

we did both use the same engine builder.

On 9/13/2021 at 3:49 PM, Dave McDonald said:

I believe 260 bhp has been achieved - but not for long if you get my drift.

240 is a more realistic reliable figure from several full race engines, all built by several different specialists, with steel crank and rods, forged large bore pistons, special head gasket to suit, high compression, high lift cam, roller rockers, 6 - 3 - 1 exhaust, lightweight skeletal flywheel, gas flowed head and an ATI harmonic crank damper. Triple 45DCOE carbs. They will run to between 7200 - 7400 rpm but max power will be at around 6800 rpm. 

Dave McD

Ditto 

i have dyno readings showing these figures

 

ROY

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On 9/16/2021 at 5:18 PM, stuart said:

Horsepower is how fast you hit the tree, torque is how far you moved the tree.

Stuart.

Trees hardly move, even when hit full force by a car:

 

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+1 with that.

Mick Richards

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5 minutes ago, roy53 said:

open wallet and close eyes.   :o  -_-^_^

and repeat after me "Help yourself!" :lol::lol::lol:

Stuart.

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Can I reopen this line of thought as we have discussed max BHP then agreed that Torque figures are perhaps more significant

What FTlbs torque have been achieved with four cylinder and six cylinder cars

I was trying to sell my racer and put the car on the rolling road with AP in Blidworth  results were:177 BHP @6575 revs and 150Ftlbs @ 4990 revs

Engine as full race as i can make it to FIA spec (87mm pistons)

Any other offers?

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Hi Michael...flywheel ?

Mick Richards

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The figures for my car in 1988 164 lb ft torque at 5300 revs and 165 BHP, at the wheels. 

That's with 89mm pistons standard crankshaft but stroked and using -60 thou big ends, with standard con rods and with 45 Webers fitted. I used a 6000 rev limit with a limiter at 6250 revs.

Mick Richards 

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Very impressive and interesting, your engine is 140cc bigger and with the standard crank stroked to 60 thou - I make that 93.5 stroke and +2mm piston size, your engine is 6% bigger and 10% more torque and at higher revs. the other difference is that I run 48DCOEs and you run 45s

Perhaps I should run 45s?

Any thoughts out there

MichaelH

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