Dyno results, from this weekend...

[E30Classic]

Had a dyno run this weekend and wanted to see how my baby is doing...

-Mustang load-bearing dyno in Lake Placid, NY
-Completely stock engine/drive-train
-93-octane, no additives or anything
-Castrol GTX 20w50...
-273k miles M20 2.5L 325i......
-engine compression:
Cylinder 1: 172 psi
Cylinder 2: 171 psi
Cylinder 3: 169 psi
Cylinder 4: 168 psi
Cylinder 5: 171 psi
Cylinder 6: 168 psi

[amdspitfire]

not bad numbers for a mustang dyno

[E30Classic]

not bad numbers for a mustang dyno

:)

[delatlanta1281]

Was your motor rebuilt or something? thats great compression

[E30Classic]

Was your motor rebuilt or something? thats great compression

I don't know, but I'm beginning to think so...... 273,000 miles, and wow!

:)

Thanks for the nice words.

[gedupsound]

nice man. For comparison, i dyno'd my iS just a few hours ago on a dynoject, pulled 148hp 150tq second run, 146hp 148tq 1st run. temperature was mid to upper 40's. mileage 160,500'ish miles. no mods, bone stock.

[E30Classic]

nice man. For comparison, i dyno'd my iS just a few hours ago on a dynoject, pulled 148hp 150tq second run, 146hp 148tq 1st run. temperature was mid to upper 40's. mileage 160,500'ish miles. no mods, bone stock.

Yeah man exactly, Dynojet numbers are a joke..... When my numbers worked out to over 180hp crank on a purely stock engine on a dynojet (151rwhp) and stock rating is 168hp when the engine is new, it was time to get a real dyno run on a Mustang.

[nando]

Yeah man exactly, Dynojet numbers are a joke..... When my numbers worked out to over 180hp crank on a purely stock engine on a dynojet (151rwhp) and stock rating is 168hp when the engine is new, it was time to get a real dyno run on a Mustang.

that depends on what # you are using as a correction factor. it sounds like you were using almost 20% which is pretty optimistic.

basically, using a WHP number to calculate crank HP is retarded - unless you have a way of measuring the real drivetrain loss, it's just a guess. it also completely misses the whole purpose of a dyno..

[E30Classic]

that depends on what # you are using as a correction factor. it sounds like you were using almost 20% which is pretty optimistic.

basically, using a WHP number to calculate crank HP is retarded - unless you have a way of measuring the real drivetrain loss, it's just a guess. it also completely misses the whole purpose of a dyno..

17%, which is what everyone uses for these cars. It's not "just a guess". (BTW, at 20% I would rank at nearly 190hp stock, according to Dynojet lol) But you're right, real world hp at the wheels is all that matters... and to get an accurate number for that, don't use a dynojet :) Dyno Dynamics or Mustang are your best friend. Dynojet is for ricers who want inflated numbers.

[nando]

17%, which is what everyone uses for these cars. It's not "just a guess". (BTW, at 20% I would rank at nearly 190hp stock, according to Dynojet lol) But you're right, real world hp at the wheels is all that matters... and to get an accurate number for that, don't use a dynojet :) Dyno Dynamics or Mustang are your best friend. Dynojet is for ricers who want inflated numbers.

yes, it is just a guess. where did "everyone" get those numbers? BMW? an angel?

you still don't get it.

[E30Classic]

yes, it is just a guess. where did "everyone" get those numbers? BMW? an angel?

Help yourself to some books on dynamometers, and use the search function. Lots of helpful stuff out there for you.

[SA E30]

So what you saying is that all cars have a 17% loss in power from the drivetrain... Thats not quite true, and even a car with different diff oil to another identical model will make different no's ... so drivetrain loss is relatively inaccurate.

[E30Classic]

So what you saying is that all cars have a 17% loss in power from the drivetrain... Thats not quite true, and even a car with different diff oil to another identical model will make different no's ... so drivetrain loss is relatively inaccurate.

No.

17%, which is what everyone uses for these cars.

a.k.a. normal 5-spd, rear wheel drive, two CV shafts in the rear E30s.

The best way to calculate this is to get an engine dyno, and dyno the engine alone. And then dyno the entire car with the engine reinstalled. Then compare the numbers.

drivetrain loss = (1 - [ (car dyno hp)/(engine crank dyno hp)] - dyno correction factor) x 100%

If you try this as an exercise with the figures from my dyno sheet, this is an approximation, you get something like:

drivetrain loss = (1 - [ (132.8hp)/(168hp)] - 0.04) x 100% = 16.95%

Now, my crank hp may or may not be 168hp as rated from the factory, so as an approximation we see, 17% is a good number to use.

Hope that clears it up. There's lots of literature out there on the subject, and lots of books rich with info. Don't be shy. :)

In any case, I was just using 17% as a GENERAL APPROXIMATION. 20% is just as good, or 15% to show you that a stock M20 on a Dynojet throwing down 150hp is bogus numbers. That would give less than 10% drivetrain loss too.... It's funny you guys didn't care to comment on that :)

Personally, I'm concerned only with dyno wheel hp from load-bearing dynos... I urge you to take this drivetrain loss discussion to another thread. THX!

[nando]

No.



a.k.a. normal 5-spd, rear wheel drive, two CV shafts in the rear E30s.

The best way to calculate this is to get an engine dyno, and dyno the engine alone. And then dyno the entire car with the engine reinstalled. Then compare the numbers.

drivetrain loss = (1 - [ (car dyno hp)/(engine crank dyno hp)] - dyno correction factor) x 100%

If you try this as an exercise with the figures from my dyno sheet, this is an approximation, you get something like:

drivetrain loss = (1 - [ (132.8hp)/(168hp)] - 0.04) x 100% = 16.95%

Now, my crank hp may or may not be 168hp as rated from the factory, so as an approximation we see, 17% is a good number to use.

Hope that clears it up. There's lots of literature out there on the subject, and lots of forums rich with info. Don't be shy. :)

yes, that is the best way - but nobody has done this for the E30 afaik, so you're just pulling the numbers out of the air. who knows how much your engine is making at the crank. maybe it's a strong motor, maybe it's down on power. how would you know unless you had it on an engine dyno? you don't.

and this misses the whole point of going to the dyno: getting a baseline, doing mods, tuning, and getting an "after" dyno plot to compare the gains with the baseline. this only works if you use the same dyno, with similar conditions. you can't compare dynojet #s to a mustang dyno, or mustang to dyno dynamics - they all use different measuring principals, correction factors, etc. just getting a baseline and then bragging about your #s completely misses the point, regardless of the particular make of dyno you're using.