engine and drivetrain Realistic Horsepower Numbers

[tim385]

Here is some figures

286 cam, 2 x45s, 9.2:1        83kw   ATW      this was a while back.

Today:Different car,  stock cam, single 32/36 weber, flat top pistons 8.5:1(might be 8.2 cant quite remember), exhaust stock but no centre resonator . 3.64 diff, 50kw  ATW  So theres a base mark to start from.Im thinking of putting the Lynx manifold and weber  on and re dyno just to see the differance.

[Conserv]

So 98 from the factory (75 carbed)

I've never seen or heard such low numbers. What's the source of these? Could these be rear wheel horsepower (I don't know how to reconcile them with the factory-published numbers)? Depending on specific year, carbed cars are generally 96-98 HP, fuel-injected cars are generally 125-135 HP, and factory turbos are 170 HP.

I am referring to 2002s. Maybe your 75 HP represents a 1600 (or 1502), but the 98 HP fuel-injected remains unclear.

Steve

Edited May 11, 2013 by Conserv

[M3M3]

i believe the "75" number he is using refers to the year of the car.

[Harv]

75 could be somewhat expected at the wheels if the carburation and or ignition is not set up correctly. There is a lot of power to be had in the final tweaking of the setup. Especially with side draught Webbers.

John

Edited May 11, 2013 by Harv

[Preyupy]

13:1 and a Schrick 336 cam, full hemi combustion chambers and a lot of port work. 48 mm carbs

[kbmb02]

13:1 and a Schrick 336 cam, full hemi combustion chambers and a lot of port work. 48 mm carbs

Those are impressive numbers in the high RPM band. (Let's hope this doesn't get folks doing the 'wrong' kind of port work (it's mighty easy to lose performance/power....)) -KB

[Tommy]

Those are impressive numbers in the high RPM band. (Let's hope this doesn't get folks doing the 'wrong' kind of port work (it's mighty easy to lose performance/power....)) -KB

Those are really impressive figures but I don't think that's the reliable power what thread starter was thinking. Thats about the maximum what can be taken from a really well built racing engine. It can still be reliable but the service interval is measured in hours - and the service means something else but oil change. Would you like to tell more about what that thing needs for service?

 

  Tommy

[jrkoupe]

preyupy...

 

geez those numbers are alluring.......yeow....

that engine may last like what...1 yr?...

[tim385]

ATW ....at the wheels , A new 2002 was 100hp at the engine...ie 75KW 

When getting a car dynoed make sure the dyno has been recently calibrated the difference can be quite a lot , I had the same car put on different dynos ,one calibrated recently one not the difference was 12 kw (atw).

[M3M3]

calibrated or not, chassis dyno numbers vary wildly by manufacturer of the dyno.  comparisons between runs on different model of dynos are useless.  chassis dynos are really only good for comparing modifications to the same car on the same dyno under the same conditions.  they are relative numbers.  eg...dynojet brand numbers appear to be consistently 10+% higher than numbers from a mustang brand dyno....even when "calibrated".

[Preyupy]

I totally agree, comparing one dyno to another (either chassis or engine) is worthless, there are so many variables. You need to start every run from the same engine speed, Oil temp and water temp to make true comparisons. Back to back runs without making any changes other than 15 deg F more oil temp can make as much as 5 hp difference at 200 hp. Race of acceleration (adjustable on most engine dynos but not on most chassis dynos) can make a huge difference in both torque and HP numbers. Some dynos seem to be calibrated in Clydesdales while others in Shetland Ponies. I use the same engine dyno every time and we have a chassis dyno, I have compaired engines right off the engine dyno and then on the chassis dyno and I know how these two dynos compare but I can't speak for any others.

If you are running a M10 over 7500 rpm on a constant basis you need to do major services (sharpen vlaves and inspect bearings min)every 35-50 hours. You can usually double that by keeping it under 7200

[Conserv]

i believe the "75" number he is using refers to the year of the car.

Now I understand! Thanks, Marshall.

Regards,

Steve

[pkchopp]

JE forged pistons,92mm / 10.4:1 compression. 144mm pouter forged rods, W lightweight  20 mm pins, Total Seal gap less piston rings, Balanced and Blueprinted crank,  Ported and polished Head, 63mm chambers, Stainless Steel valves 47mm int. / 39mm exhaust, Triple racing valve springs, Titanium retainers, Shrick 304 cam, peened and polished rockers, cometic head gasket, ARP head studs, Aviad high capacity oil pan, Dual 45DCOE Webers, XDi crank fire ignition, ITG air filters and so much more..... cant tell you what the Butt Horsepower is, But I know the PUCKER factor numbers are high!

Edited May 12, 2013 by pkchopp