Thought I'd share this dyno result from earlier this year (see attachment). Assuming the usual 15% discount from crank to wheel, my best run at 302 WHP nets to about 347 at the crank. This is after my 2017 major, which sorted a few things and included a good scrubbing of the injectors, but nothing else notable. Curious if others have recently dyno'd and where I fall. Wasn't expecting to get the book number, but I thought it might be a touch higher than this. Image Unavailable, Please Login
Pretty good numbers (comparable to other 2.7's I've seen) but may be room for improvement. Looks like it peaks earlier than what I would expect. (cam timing?) This is mine with capristo, test pipes and secondary cat delete. Image Unavailable, Please Login
its in another thread.. but I took notes so I wouldn't have to look it up again.. there was a point I was maybe going to dyno my car.. but then never got around to it. as per the thread.. I believe one of highest known made 325whp, which I believe was on a DynoJet.. not aware what type of exhaust mods there were.. and the averages are 2.7: 290-310whp 5.2: 280-300whp so I think your 302whp is right in the ballpark what to expect..
Cars like Mustangs and Vettes have a transmission whereby in 4th gear the input shaft is coupled to the output shaft with a dog and no gear is used in transferring power from the input shaft to the lay shaft with another gear transfering power from lay shaft to output shaft. These cars do have a differential post transmission. So in 4th gear the power goes from the clutch to the differential with no gears in the way, the the differential swings the power 90 degrees to drive the wheels. In the F355, the input goes through the drop gears(1), a bevel gear (2) to change directions onto the main shaft, over to the lay shaft(3), and up to the output shaft(4). No less than 4 sets of gears are used in transmitting power. So one is comparing the efficiency of 4 sets of gears with 1 set of gears and claiming that "it can't be that much worse". I am not of this belief. But, the F355 transmission has small shafts supported with multiple ball bearings on each shaft, so I can agree that the loss per gear is probably a bit less than the Mustang/Vette arrangement--but NOT THAT MUCH less. I would enjoy seeing an F355 engine run on an engine dyno, then bolted to a car and run on a chassis dyno just to determine what the loss number is. I don't think anyone would want to pay for this, though. I am sure Ferrari has the numbers.....
Those are definitely eye-popping numbers. Not sure if exh, test pipes and cat delete can account for that much more pop than my (very stock) setup. Yours a 2.7 too, I take it?
If the OP has air/fuel ratio it would help in understanding the minor dip in the range 6,000-7,000 RPMs.
Mshobe, I dyno'd on the same dyno a year ago. See https://www.ferrarichat.com/forum/threads/dyno-day.554575/#post-145436195 essentially 300/220 Mine is a 2.7 and at the time it had a custom header (which I think is robbing me of torque) hiflow cats and a capristo level 3 sound. Here is the youtube run
My car was dyno'd 4 years ago after its engine out service. 2.7 Spider with Hi Flow Cats, Fabspeed Headers, and Sport Exhaust with a Capristo bypass... I cant find the sheet, but I believe it was 318 to the wheels... which i was told was a very impressive number for an F355
I doubt it's because of the cat delete. It made 327 with high flow cats and the same y-pipe (but still peaked at the same rpm). Yours is peaking a bit early for some reason. Mine is a 2.7 car.
Different dyno's different days etc. A 335 RWHP dynjet run at 74 degrees, 1200 feet above sea level, 60% humidity, well warmed car, minimal fans, may dyno slightly differently at 76 degrees, 800 fee, 42% humidity, with more fans. While it isn't going to be 20hp difference, even the same car on the same dyno at the same time can wield a 1-3% difference. Even tires and rims make differences. On my other more powerfull car, there is about a 9 lb difference in wheel weight between runs and guess what, the lighter runs were all averaging a few hp better. If a 2.7 with no known issues did 275 on a dynojet 2 wheel, ok, that'd be something to know bout 290-320 should be the range and a 300hp run on one dyno and a 320 on another may not mean the 320 actually has more hp if run on the same dyno. Mshobe, the dyno in kirkland seems to be very accurate but some other dynos could be adjusted differently. Really the best use of a dyno is to do a before and after perf parts to see the gain/loss.
Definitely some variance between dyno's/runs but ambient conditions shouldn't be a huge factor unless we are talking uncorrected numbers. Yes lighter wheels will dyno higher as it consumes less power to accelerate less mass. All 3 cars here are running original wheels I believe. The difference I'm seeing is the curve. Factory rates peak power at 8,250 so if it's peaking early at 7,750 there's is some power to be found somewhere. (mshobe graph). schnazzy, your car they chopped the runs a bit early but it seems that it would have made peak power at the right rpm at least.
Yeah tell me about it 90 degree day dyno run vs one in a wind tunnel dyno 70 degrees sea level in morning looks like a different car
Yes, agreed on airflow being necessary. Everything remaining equal, corrected numbers -should- be pretty close day to day. I've ran cars on the dyno 1 year after tuning them and had graphs overlay almost exact in different temp/baro. Not saying this is always the case for every dyno but I would say if results are varying wildly with ambient conditions something is not calibrated correctly.
yep, 302 good! we had to dyno the 355 Challenge all the time for NASA and it was 305-320 with a blueprinted high rev'ing Ferrari of Houston build.
Agreed. And while I've not used a mustang dyno it's my understanding that user input can greatly skew the corrected numbers. Not able to be manipulated on a dynojet so to have large variance you have as you stated operator error (or inconsistency) or the weather station is jacked
