308GT4 Power outputs

Hi Dan

I have no real knowledge to back it up and haven't had mine on a rolling road...but magazines often quote the twin distributor Series 1 as a more powerful engine. Is this just an old wives' tale or is there any real basis in fact? I'd love to hear an unbiased view from "someone who knows"...maybe I should arrange a head to head with Richard's !!

 

IIRC, the 1975 US version listed 240hp (US version- European was listed as 255). The 1978 dropped to 230? then 1979 dropped to 205. These are numbers that I've seen, I believe, in Keith Bluemels 308 book. (I am out of town for the next few days, so I can't check to be certain). I also remember reading in an article (I think it was the Forza 308gt4 buyers guide) that one magazine reported a faster 0-60 time for the 1979 model, in spite of the HP difference.

I won't be back home until friday, so I can check then, but if someone else has these references, they can confirm my numbers.

Here in Cali, the big advantage of the series 1 cars (1975) is that they are smog exempt. 1976 cars and newer require a smog check.

Dom

 

I believe Kieth Blumels book, or his source, is in error regarding 28 ATDC exhaust close on the later cars. Its most likely a typo and should probably be equal to the early cam.

255 HP is what Ferrari quoted on the early euro dry sump engines, 240 on the wet sump US cars? I think the 255 was blue sky out of a blueprinted engine, not a off the shelf consumer car. Could 4 degrees change in intake valve timing be worth 15 HP? There just havent been enough dyno runs published to validate any particulars. And on the few dyno sheets available, we have no information as to exact valve timing, ignition timing, jetting, or muffler, and there is also the question of actual calculated compression ratio? We really would need that data in order to truely know what works.

 

From the "Ferrari Buyer's Guide", by Dean Batchelor (1996 - 4th edition)
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Here is an actual engine dyno of Tate Casey's former EURO 308GT/4, which was tweaked on the dyno to the nth degree, stock except for a tubi exhaust (see at http://www.carobu.com/html/308gt4_euro.html ):
3.0 2v
Bore: 81 mm
Stroke: 71 mm, Compression Ratio: 8.8:1
Heads: stock (no flow chart)
Cams: std. factory Euro grind (233°/225°, )
Induction: 40 mm Weber DCN on standard manifolds with factory air box and filter
Exhaust: factory headers port matched with Tubi muffler

I think this is a good reading on an early Euro GT/4 at the actual engine. I think these early carb V-8s are pretty amazing at an 8.8 CR - you could probably run regular gas.
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*WOW*....those are really impressive numbers for the engine! Assuming a 10% drivetrain loss, that back calculates to 260HP at the crank, and assuming 15%, it's 275HP at the crank. I suppose 10% loss is more realistic for a manual tranny, but still, damn good numbers for a stock motor.

 

No, unfortunately, those are numbers on the actual engine OUT OF THE CAR at the crank. To get at the rear wheels would multiply those numbers by 0.83 to get the more usually compared rwhp numbers.

On another note, the usual loss quoted for transverse mounted V-6's and V-8s is nearer 17%; 348s can lose even more.

Man, I wish I only lost 10% on my driveline...

best
rt

 

Dom,
US Series 1 GT4's are 255hp (euro spec) the cams are different, so is the timing. Many techs time US series 1 cars incorrectly and rob them of a few horses.

 

I believe the power on the US cars, all 308's, dropped from 240 with the introduction of catalytic converters for the 1978 model year. Along with cats it got the strangled camshafts. Its also my understanding that power on US cars went directly from 240 to 205, with the 230 HP figure indicated for the later euro cars.

 

So would I take an educated guess and estimate my 1974 Series I euro model 308 GT4 at 255 hp?

EuroDino (#08140)

 

234.8 x .83 = 194.4 That is ~10 hp more than my 1978 308 GTS makes at the wheels. Makes me wonder if Euro cams are really worth the price.

Aaron

 

i thought 205 HP was the lowest number reached on the 308s, but that was with the 2v fuel injected version...and that the carb engines were all above that... ???

 

205 HP is the lowest number that appears in the documentation (same "spec" given for both late carbed and 2-valve "i" US 308). Maybe, in truth, the "i" could be less than the carb, but you'd need to compare the average of a properly-running population of each and that's hard to come by now ...

 

There are lots of different kinds of hp numbers bandied about in this thread. For some of you reading this, it's important to know magazines and company specs quote power at the flywheel. Horsepower measured at the rear wheels ('rwhp') is less due to losses in the drivetrain and tires. In a transverse engined Ferrari, this loss number is typically averaging around 17%. So in some of the posts, the rwhp is divided by .83 to approximate the flywheel hp, and flywheel hp is multiplied by .83 to approximate at the wheels.

Hp can also be quoted by different standards that are not the same, such as DIN and SAE. Currently, the same engine will have a sl. higher DIN rating than SAE. In fact, the SAE standard changed itself a couple of decades ago so the old SAE and new SAE are not exactly the same.

That is why rear wheel dyno numbers are best for comparing a car to itself after modifications, which keeps the confounding variables (tire friction, etc) more constant.

 

Sounds like a challenge David!!! Yes, it was me Dan's been chatting to about bhp figures.... I brought this up I'm afraid. Mine's in good condition I'd say, but certainly dosen't feel like 255bhp. I did a 15.79 1/4 mile at the Brighton Speed Trials (with Dan) if anyone has some road tests to compare that figure with???

My view is, that whatever you "may" loose having a later car.... you make up with having (IMO) a tidier front end.... inertia real front belts and 3 point static belts in the rear.

In reality.... apart from dead straight dual-carridgeways, you are never left behind in a GT4 'cos they handle better than most Ferraris.... just don't slow down for corners!!!!

 

Richard

Digging in the Gold Portfolio magazine reprint book gives the following 1/4 mile figures:
14.6 (Road & Track in Europe Sept. 74)
14.5 (Autosport Dec. 74)
15.6 (Car & Driver June 75 - a USA car quoted at 190bhp SAE)
16.0 (Road & Track Nov. 79 - quoted as 205bhp SAE)

We know they are never going to feel that quick in a straight line, especially nowadays but that's not why we bought them is it!

 

Hmmmmmmm. must try harder it seems!!! Though, if a '74 car that you quoted with 255ish bhp does 14.5 or 6.... my later car with 20-30 bhp less might be just over 15 secs.... I need some more practice.

I suggest you enter the Speed Trials next year also... we can have a propper old "grudge match"

 

Congratulations Dan..... Let's have a bit of a GT4 'fest.... get David along, and may the best man win (now, where is my Demon Tweaks brochure) ????...........