Particularly slow off the line - is this normal?

Stock? Year? carbs? You will probably need to provide some more detail on your car for others to help. Mine is modified and sluggish at low RPM as a result. But expected because of the mods.

 

I tend to agree with you. The experience with my '76 Euro GTB is much the same as yours. These cars were not exactly jackrabbits off the line. It has been my experience that if I want a reasonably quick start in first gear I have to feed in a bit more RPM than one might think, and release the clutch a bit more abruptly. I'm not saying high revs and dump the clutch, but just a bit more aggressive. Beyond that, the experience is a pleasure. That being said, on a level roadway I can pull away in first at idle with careful release of the clutch. On slight declines I avoid 1st altogether and pull away easily in 2nd. These motors tend to be pretty usable torque-wise, but the most fun is in the 2nd thru 4th gear range which seems to keep the motor in its sweet spot for torque and power. If I'm over say 3000RPM in 5th gear I can easily accelerate up a moderate incline. Having been used to low-revving, understressed American V8's with effortless bottom end grunt, the 308 was a revelation; a much more engaging driving experience.

 

When mine was stock (84 QV), getting it to leave fast meant bringing it to about 4500-5000 and dumping the clutch....now I can't even use 1st gear because it just spins uncontrollably, what a difference an extra 600hp makes

 

The torque in these twin cam motors are higher up the rev scale than a traditional Chevy V8. Rev it and slip the clutch just a tad or drop the clutch. Where the Chevy runs out of gas the Ferrari is just getting going.

Basically, drive a bit more aggressively. That's the fun of it.

 

That sounds more anemic than normal -- I don't have to be extra careful going through a stop sign in my 1.5L Honda . A couple of initial easy things you could do are:
1. Confirm that intake vacuum is reaching the Digiplex ECUs (i.e., the vacuum hoses are OK, connected, and you can "feel" the idle vacuum is present at warm idle with a fingertip on the end of the hose if unplugged), and
2. Just unplug each vacuum line going to the Digiplex ECUs at warm idle one at a time (and block the unplugged line with a finger tip leaving the port on the Digiplex open to atmosphere) -- the warm idle speed should increase. If it doesn't = not a good sign for the vacuum LVDT gizmo inside that Digiplex ECU. (When typical intake vacuum is applied to the Digiplex ECU at warm idle, it sets the timing to -3 deg ATDC; when no vacuum is applied, it sets the timing to 6 deg BTDC. I.e., when sitting at the stop sign, the engine is idling at -3 deg ATDC, and when you open the throttle to go, the vacuum decreases and the ignition timing is advanced which helps with getting going.)

 

I agree with Steve. An 84/85 QV has good low end torque and should leave the line pretty strong without much clutch slipping or RPM.

Something is wrong.

 

IMO, no different than any car that does 0-60 in 7+ seconds.

 

Is the slug zone rpm related? Like once you get above x rpm all is well? Nothing should change 1st to 2nd gear other than the min rpm. Or perhaps there is an ignition issue and 1/2 the engine is shutting down at idle and just kind of cutting back it with rpm/shift?

These things aren't fast but it should accelerate much quicker in 1st than 2nd.

 

Same car, 85 QV. Not a slug form 0-15.

 

Unlike many here I am going to trust you can tell the difference between a new 500 Hp car and an 80's 240 or so HP car. Does it accelerate like an 80s top of the line sports car? If not there is something wrong. My bet is your car has an issue. With the clutch out and moving slowly in 1st and just planting the throttle it should come near spinning the tires. If not, your instincts are correct. Ignore the noise here. Some, most actually cannot help but muddy up the water on everything.

 

I'm on the east side of CT. But actually, I was thinking a lot like Rifledriver. These are not muscle cars. They aren't gear to be particularly quick off the line. But if you start form a dead stop and work the clutch properly the car should accelerate smoothly in 1st, ans then 2nd , etc, until you reach cursing speed. If you want it to come off the line stronger you have to get the revs up and slip the clutch, much like launch control. Of course, do that and you'll wast the clutch pretty quickly.

 

That was my finding too so my first though when I read the thread was it's a 3k lb car with 3 0l engine that has a 5k rpm torque peak....fast at 1500 rpm it ain't. Above 3500 though is quite nice. There could be an ignition advance issue as Steve suggested, but if you're saying it wakes up at higher rpm....well that's kind of normal. The only way I could get a decent launch out of mine was the 4500+ rpm clutch dump I mentioned and why my 1st order of business was adding more power. I found it fun to drive stock, but a dragster is certainly wasn't.

 

There is no replacement for displacement, 5.4l makes a lot more torque everywhere than a 3.0l. I have a 5.4l v12 in my 308, it accelerates at low rpm like the 3.0 could never even dream of. I had a couple different blowers on the 3.0, and that made a huge difference in low end performance.

But the graph you posted tells you a 308 is faster than a 928....if you rev it

 

Sorry, only 50% bigger with 50% more torque. That is a big difference though, and why when you say slow in 1st, I wonder if you mean slow below say 3k rpm and you only ever do that getting started in 1st? Below 3k the 928 will just destroy a 308, but if you keep the 308 above 5k you will get a different result, it's a small engine that needs rpm to make power.

 

I think we should have a rule that whenever you post about the V12 in your 308, you need to post a photo for our enjoyment.

 

Lol. This is a slow acceleration at low rpm thread so maybe not slow acceleration at low rpm?

 

[emoji23] nice.


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