low end grunt

i'm always impressed by how much grunt the 308 develops at low rpm and relatively high gears. for what was a high rev engine in its day- not known for lots lof low end torque -drive a 63 alfa some day. can someone tell me what are the design features of this engine that makes it such a stump puller? thanks and cheers. jon s

 

Most Ferrari engines have been tuned for a wide power band.

 

My guess is cubic inches. I have a '91 Alfa 164S and it's 3 liter V6 displays a similar "grunt" despite the heavier chassis and about 30 less HP.

 

All of the CIS injected F models have a (relatively large volume, long runner) resonate intake system (that flows best at the low frequency pulsation of low RPM operation) - this boosts the low end torque while slightly penalizing the high end torque = which gives the "flatter" behavior that you are noting. The carb models (small volume, very short runner) tend to be more docile at low RPM but scream harder at high RPM than the injected models (which is why your carbed '63 Alfa seemed wimpy at low RPM, and why a 365GT4BB has a higher maximum HP rating than a 512BBi, but a 512BBi has much better low end driveability).

 

How about 2V vs 4V? That probably has some effect too.

 

I have driven a QV for nearly 20 years.

Last winter I brought home an 80 GTB to play with for a week or so to see if I wanted it. Stock engine with the exception of electronic FI with an electromotive ignition.

It pulled from a dead stop 100% harder than any 308 I have ever driven. It wasn't more power, it just felt like the timing was better optimized. I loved it.

 

Well that kind of negates the "stock" part but from what I've read on the subject the 4 valves favor the higher rpm's and while the 2 valve injected engines were down on HP in original form they may have always had a bit better low end "grunt". This I don't know from experience, I've never driven one.

 

When I said "stock" i just meant the long block is factory. No high compression pistons, cams, things like that. Just the same vanilla 190hp or so 2Vi motor.

 

Wow, I was trying to figure out if I may have been in the wrong sub-forum, but it seems like we are indeed talking about 308s!

While I love my 85 QV, "torquey" and "stump puller" are about the last adjectives I'd use to describe my beloved car (as well other 308s I've driven). Must come down to differing definitions as I've never driven a 63 Alfa!

No matter what the adjective, enjoy these undoubtedly wonderful cars!


Cheers!

Ruben

 

Yes I understand that, I'm just saying that a fully closed loop EFI system is going to have an effect on the performance attributes you are citing so a head to head comparison with a CIS injected QV can't really answer the question - is it the 2 valves or is it the EFI?

Which brings up another question - why didn't Ferrari go with EFI on the 308 and 328? I'm pretty sure L-Jet came around in '81 or '82.

 

The EFI

It really woke up that engine. Surprisingly well.

 

thanks guys i enjoyed your replies. tom: i put an electromotive ignition in my 81 gtsi and changed the timing way away from stock maybe that helped. cheers, jon s

 

steve : i think you must be right

 

You need to drive a 3.4L, you wont be able to get your cheque book out fast enough.

 

I know. I was within an eyelash from pulling that trigger last winter when something else came up and I had to use the checkbook for a different investment. I had even spoken to Carobu a few times.

It will happen one day.

But back to that 81 GTB. It didn't have more power - the power band had just shifted like putting in different cams or something. My QV takes a second or so to "catch up" with the throttle from a dead stop when the clutch is released. I had a 83 928 that was the same and I guess it is just the inherent delays with a very simple basic CIS (although the 928 was L-Jetronic vs the 308's K). Carbs don't have that from what I understand. Nothing wrong with my car because it feels like every other QV I have driven.

With the EFI/Electromotive it felt instant off the line which gave the perception it had a few extra hp under the hood.