how many rear wheel horsepower ?

I can't imagine it would be that much... probably not enough to notice, IMO. But
I'm sure Rifledriver and others will chime in.

Jedi

 

I cant answer the question either but I would be surprised to see 200 RW HP from a stock 308 GTS/i

 

This^^^^^

From my understanding most are going to be in the 150-170 rwhp range. QVs reportedly are in the 180-190 rwhp range. I know of one person on here who may chime in that does have his carbed GTB up at 199 as measured a week or two ago. He can comment on what he did to get it there, but I am sure it was a pretty good bit of work.


PDG

 

Those stock 2vi engines are lucky to get 205bhp at the flywheel let alone the wheels. Nick sells an excellent injection system for the 2vi engines. That combined with his ignition system will get them to 195 at the wheels. Nick posted a dyno sheet and has a couple good videos on youtube showing the system. Very nice bit of kit. Quite a bit of work involved but evidently worth it.

 

The K-jet system is quite efficient in itself but one key advantage of EFI is the ability to program it right up and down the rev range, meaning better efficiency and maybe better smoothness and response. But, with nothing else changed, I'd doubt you'd get more than a few percentage points increase in HP.

 

I had my freshly rebuilt GT4 engine with HC pistons and some minor porting with Crane electronic ignition and X-ost exhaust and I got 195 RWHP....but in saying that my cooling system at the time,mainly the radiator,wasn't in tip top shape and I had to stop the dyno runs as the car began to overheat...Also the car was running pretty rich also so that may have cost a bit of HP as well..I subsequently had the radiator recored and fitted larger more efficient fans but never got the car on the dyno again...I have since sold the car.

 

Sean (luckydynes) has exactly the set-up you are talking about, but bumped the compression up to something crazy, 11:1 I think and is making 220 rwhp if I recall. I would expect you’d pull about 200-210 with stock compression. Installing the early carb cams should be good for another 10-15 hp I’d think

 

Sean's showed 210 at the wheels if I remember right, and that was with CIS cams! Great little engine.

 

What are the numbers for a 83-84 Euro QV.

 

Anywhere from 190-200 on a dynojet. The thing about QVs and Euro engines especially is their lack of torque at a reasonable rpm. For instance. I have a dyno sheet showing a Euro QV putting 200bhp down at 7000rpm and 168lbs peak torque at 5600rpm with a very peaky torque curve. As in; no bottom end at all, and then over 4500rpm things wake up a bit.

 

213 rwhp on my Dino...

Stock 1974 cams and pistons
BSM electronic ignition running on standard timing
X-OST muffler

 

Weren’t the early engines rated at 255? That would put yours right on target.

 

Yeah "rated" with a drysump in a GTB but "Actual" is another story.

 

it looks like Hans' makes it, at least with the mods he's done.

 

Even magazines of the era stated Ferrari's numbers were high with the actual figure being between 225-235. Carobu port matched, degreed cams, used proper jetting for power but otherwise used stock everything else and came up with 229.5 with a stock exhaust and 235 with a Tubi. Flywheel numbers.

I don't know what kind of dyno Hans used so I cannot comment on his numbers, but the above engine I mentioned is as perfect as a stock Euro engine can be with stock components.

I will eat my keyboard if a bone stock engine makes much more than that. (+-5)

 

He said his engine is stock untouched inside and original. A rebuilt one doesnt make that HP so hogwash to 17% losses, strap it to an actual engine dyno and get a direct reading, then the tears will flow lol.

 

It just doesn't makes sense. The bhp of an engine running 10.5:1 cpr and considerably hotter cams is barely making that sort of rear wheel bhp. Heck, a P6 engine with high cpr probably will barely make that. No one is gonna make me buy a stock engine making that kind of power. The dyno is either calibrated differently or it is as Paul said, hogwash.

 

"If a stock 308 GTSi has say 200 HP at the rear wheels, and i were to replace All of the bosch K Jet fuel injection with a state of the art electronic fuel injection with 24 lb injectors, zero restriction air cleaner (ie. no bosch pie plate airflow meter) but keep the original Ferrari 70mm throttle body and Plenum, how much rear wheel horsepower increase would we expect to see ?"

None. Nothing you are talking about would add any HP.

 

It was measured on a Dynojet at a reputable shop here.

As I wrote John:, I've run my car against a Euro QV with Tubi and we were dead even from 40 mph all the way to 140 mph. Against a known very good Euro 328 with tubi, the 328 was only inching away from me. Flat out, I've run 7800 rpm in 5th gear with the car still accelerating (indicating 165 mph).

I think I simply have a very good one.... Lucky me!!

Hans

 

I am sooooo jealous Hans, we don't have anywhere where we can do those speeds. I'd love to put the 308 on the Autobahn.

 

This leads into the really interesting debate about different dynos. Here are some of the variables:
* Brands of dyno
* Engine versus chassis dynos
* And with chassis dynos, is it roller-based (with the tyres driving the rollers) versus hub-based (with the wheels off and the hubs bolted directly to the dyno).
* Different resistance systems (mechanical, fluid, etetera)
* Ambient temperature, air pressure (c.f. altitude) and humidity on the day of test.
All of these things can lead to variability of readings.

Also, there is much debate about the percentage difference between chassis and engine dyno readings. We see figures like 17% quoted, but there are all sorts of other figures bandied around, most of them highly exaggerated. The 17% figure is probably close to the mark for 308s/328s in their typical HP ranges, but it does not make sense that this figure would remain constant for all engine and transmission combinations. This is because the loss of HP from engine to wheel is in the drive train. That is, the drive train takes a certain amount of energy, but it is not logical to assume that this amount of energy is in simple proportion of the output of the engine.

 

Great post. Recently I read an article about Ferrari's transmission design during the 70s which leads me to believe that even 17% is too high.

Evidently Ferrari tested these transmissions with drop gears leading to the gear box vs other style (unsure which) and came to the conclusion that more torque was transferred directly to the wheels via this system than by traditional means. Mechanically, this is over my head and I am paraphrasing a paragraph in the latest issue of Forza which reviews the system in some detail. These findings are counter-intuitive to what I had thought before.

 

Yeah, well.... to be quite honest, this was NOT on the German Autobahn... We were allowed 75 mph on that road.... Good thing we did not get caught....

(And if I was thinking I was going fast, how about that Porsche GT3, Challenge Stradale and Gallardo going flat out? The Gallardo doing 212 mph....)

 

I guess Ferrari had the luxury of changing one variable at a time (gear types) and then testing it on the same measuring device (dyno). It's nice to know we have a highly efficient drive train. It perhaps means for less "bragging rights" based on engine hp extrapolations based on chassis dyno figures for our type of cars.

But honestly, do "absolute" numbers really matter? Take Hans' car as an example. It seems to be a great car to drive by all accounts and goes like a rocket. That's all that really matters. Also, he has a benchmark figure on a known device. If he made changes to his car, he could measure again on the same device and work out percentage-wise if he was going in the right direction or not.

This is what I am doing with my car - I had it fully dyno-ed recently, and now I am changing the exhaust system. Then I will dyno it again and will be able to measure the change due to the exhaust, because there have been no other changes.