[ame]www.youtube.com/watch?v=ECNMTdu72_k[/ame] [ame]www.youtube.com/watch?v=oEm6BGwTyuc[/ame] 0-60 is probably somewhere in the low 5s or perhaps even upper 4s. I'm not going to beat on it to find out though. It's not geared as tall as an NSX in 1st and 2nd gear so it should pull through the gears a bit quicker but then again it can't be shifted as quickly either. No biggie
duhh. I actually live 10 minutes from Road Atlanta track and that was shot very near there. I'm so glad I'm out of that house we were stuck in for 6 months while our house was being built. I had zero room to do anything, now I have a shop. woo
Last week I was chatting with one of the guys at FormulaGT in Munich regarding drivetrain losses with these engines. It may be a bit higher than we previously thought because their test subject was a race-built 308 engine which flywheel dyno'd at 309bhp, and then yielded 241bhp at the wheels. That's a massive 22% loss. I couldn't have thought in my wildest thoughts it could be that high. This very possibly means our power figures are not quite as far off as the factory originally claimed. Most solid stock 308 QVs will put down 190bhp at the wheels. If 22% is anywhere near correct, that would put stock output at 243bhp (ish) which is right about in line with their claims of the day. Wild
My 308 with turbo was dynood at 240,6 hp and acc to the " general" rule of a 17% drivetrain loss i was close to 300 bhp. My hopes however where to reach beyond the magic 300 bhp barrier. With this new figure for losses i did reach it after all Thanks for this new info!!
Considering that the 308 doesn't even have a proper ring and pinion, that loss number is not believable. I would suspect that two different types of dynos being used to measure HP are more the source of the delta discrepancy.
I tend to agree, a 22% loss is massive, also it's not going to be fixed, possibly linear or slightly logarithmic but certainly not a fixed 22%. if I had the time I could sit and crunch the numbers based purely on the gears and est. the friction of oil viscosity, temp, clutch slip, diff and flywheel, etc... but it would be tedious a time consuming. Dynomometers are not all created equal and the sheer number of factors that go into a 'calculated' HP figure means that at best you could use it as a marker for changes on that one dyno, jump dynos and it's apples and oranges.
That's entirely possible Dave. This being in EU as well they could have them set up very differently than some in the states do which is why at times we see such discrepancies in rear wheel bhp figures from the US vs EU. Weird right.
Check out the German dynos Mercedes, Audi, and Porsche developed called 'Maha' for short. They are massively cool dynos that show powertrain losses at different rpms, and yes it indeed is a linear loss.
Well, since you opened the door, are we talking DIN-rated HP or SAE-net HP. As I recall, there's a 15% difference between these two ratings.
So are there modifications that could be made to reduce this loss? Many are spending significant money to increase HP, but perhaps there are also changes to be made in reducing this drag on the HP the engine makes. Aaron
Yeah, I can't believe that. My bone stock (except aftermarket muffler) euro QV made 213 at the wheels on a dynojet. If you believe 22%, that would mean my engine makes 273 hp at the crank. No way is that possible for an engine that is rated at 240 hp from the factory.
arent you contradicting what you posted a few weeks ago? http://www.ferrarichat.com/forum/showpost.php?p=141636196&postcount=189 my hunch it isnt linear given how meshing gears work and the way oil heats up
Not at all. Just new information from a very good engine builder. I'm not giving it much weight, but it's interesting. I'm still very lean north of 5k rpm, I'll get my 270 at the wheels.
I'm going to have the raw engine dyno results from Carobu soon. How much would it cost to put the car on some rollers when I get back to Denver to compare the flywheel #'s vs the rear wheel #'s. Would that be the first "side by side" example around here? Mark.
You can do that for a baseline, however considering your elevation in Co, it would be an apples and oranges comparison. Keep in mind elevation, temperature & humidity all effect the dyno results.
Both dynos will be done at roughly the same elevation (5200 feet) so the measured friction loss should be acurate. Anyone else who does one or the other should be able to get a decent estimate from that.
Just finally saw this thread - Nicely done!!!! When I get back from here I need to makea trip up to Atlanta to come see you and your family!!! I also want to get photos of the cars together since I never got to do that in Oklahoma.... PDG
Would be fantastic if you could do that, yes. Elevation, humidity, temperature are all supposedly programmed into the dyno to be compensated for, at least that's what dynojet says. They claim dyno results will be within 1% regardless of conditions, but I'd be surprised if it was 1%, heck if it were 3% I'd be pleased. Then again, their software is very good so who knows. Other things that effect dyno runs at the rear wheels are wheel weights and I don't think they are looked at often enough. A 52lbs wheel/tire is going to dyno lower than a 45lbs wheel by a solid 8-10bhp, I know, I've seen it happen. Other things like oil type and temps play a bit smaller role but still at times measurable such as a 50w non-synthetic oil will dyno less than a 40w synthetic. I haven't run my engine on a synthetic yet as I ran it with this thick 20w-50 blend which is great stuff, but I think it's a bit thick.
I guess I should put my 390's on for the roller test then. I'm pretty sure the 17" compomotives weigh more, no? How much do dyno shops charge?
Actually, just stick it on with the compomotives as you want to tune it with what you're running. A baseline dyno run on a dynojet is less than $100 and takes about an hour to set up, run it, and done.
