Dyno'd my 355 today.

95 degrees ambient temperature. car is stock (minus challenge exhaust), 41K miles. original valve guides.

Made 297.7 whp on a SuperFlow Dyno


Decent number?

 

Seems low to me. That's <350hp at the crank and near an e46 M3 dyno number. Have you had a compression test done lately?

 

Rob Lay was saying that 290's was good for a street car.....challenge cars made around 320-325-ish to the wheels. I did some snooping around on forums

 

yep...compression and leakdown were excellent at FastCars

 

Depends on the dyno. I heard that Superflow dynos about 10% lower than a dynojet. Is that an inertia type dyno?

 

That's a good number indicating a healthy motor. Arguments over a few rwhp are insignificant IMO. Now if it was -50hp to guesstimates, then yeah, maybe a problem.
Drive it like ya stole it!

 

That's pretty much right on 350 crank HP (assuming 15% loss which may be generous due to the transverse box). Doesn't sound off as that's generally where these cars seem to come in at. Highest I've seen someone report is 325rwhp for a challenge car.

 

yep, im happy with the numbers! second run was 1hp lower....but I figure the car was getting pretty hot by then

 

That sound spot on with all the dyno numbers I have seen over the years. Some claim that the 355 really had about 350 crank hp because of these dyno numbers while others say the transmission just eats more hp than most because of the design.

 

good for 95 degrees in today's weather

I'll never show my numbers, its an old racer thing

 

I always just lie about mine....
"Yes, it's only got 220hp. There must be something wrong with your car, because I never beat cars like yours."

 

Yes I am pulling the 4 litre motor soon, I have the new cradle all powercoated with new stuff ready, it sure does have a perdy mouth...



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I think a superflow is like a mustang dyno so it reads a touch lower, but not as low as a mustang dyno. I'm thinking it also matters what Input perameters are used, though I'm not certain with superflows. Even of the above were a dynojet pull, 297 is still a good number for a 355. I would also calculate drivetrain loss at 17-18% for this car, there's a lot of turns and gizzard to go through with a transverse box as opposed to a more direct input box. A 308 has about the same number of turns to go through and I know for a fact the loss is about 18% in 4th gear as I've seen dyno figures of the same engine from the flywheel to the dynojet. Tire weight also has a little bit to do with things, heavier tires on a dynojet make a small difference (lower bhp pull).

 

Looks great Tim....is it just me or is the rear most bottom cross member slightly bent..??

I have a new one if needed..lol

 

That is actually a pretty respectable number, and higher than the "average" stock 355 from my expereince. I attached a dyno that we did on a 2.7 Spider, stock vs. Fabspeed performance package. The Stock car put down 288 whp and 195 ft.lbs and after the upgrades it put down 325 whp and 234 ft.lbs. Both runs were on a dynojet with SAE correction. Shows how much potential is in that exhaust/intake..

http://cdn2.bigcommerce.com/server6100/fh9wsjv2/products/333/images/653/355_2.7_Perf_Package_Dyno__53914.1389192074.1280.1280.jpg?c=2
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Fantastic results for equipment that is bolt on.
I really like the fabspeed product. These guys bust their a** on customer service too.

 

I figure a 40 hp difference on my car between the dynopak and dynojet machines. Yes the temp and humidity - your lack of it - make a difference. So I'd say pretty good numbers for the device and climate. Come back and well take it to Churches. You should see mid 300s there.

 

That's an extreme difference. I've never seen one dyno that low before on a dynojet, something isn't right about that run.

 

Thats just the picture looks bent, I went and checked the cradle after I saw that also LOL

I have a second or should I say third cradle I am refinishing also thats what the member from you is for
Need to finish and get together so I have a spare drivetarin with a real ECU & electronics that I can swap out easy with the stock setup. I really like to play this game I', old and bored LOL

 

Guess I was off target... Didn't realize that a 355 will dyno the same numbers as an e46 M3. Seems strange since the bmw is rated at 50hp less and has to put the power through 2 seperate gear boxes (tranny and diff).

 

If you say so. Even if there was something wrong with the original run (or something wrong with our dyno) the delta would still be accurate. Not all cars are created equal!

 

A 355 with only 195lbs torque at the wheels is a broke 355. That's stock 328 levels of torque.

 

That is one awesome car you have. Love it