Poor Top-end Acceleration
Thread Starter
Racer
Joined: Dec 2002
Posts: 400
Likes: 0
From: Spartanburg SC
Poor Top-end Acceleration
My mods are listed in my sig. When the car is in 3rd gear and gets up higher in the rpms its really sluggish. I'll usually have the petal about 3/4 down, and then press it all the way down, but the car doesn't accelerate any faster than the slow pace it was already going. It does fine off the line, and at lower speeds. Is this just a lack of horsepower, or could it be something else? The timing is still stock on the car, if it was adjusted for more performance would it help correct this problem?
Burning Brakes
Joined: Oct 2001
Posts: 842
Likes: 3
From: Woodruff SC
St. Jude Donor '10
Re: Poor Top-end Acceleration (SCVetteGuy)
What gear is in the rear end? That's a start plus keep in mind these year models don't have a lot of top end. At 5k rpm mine's running about 105 and I don't won't to push it much more than that
Intermediate
Joined: May 2004
Posts: 45
Likes: 0
From: cedar creek tx.
Re: Poor Top-end Acceleration (SCVetteGuy)
What kind of speed are we talking about 110 120?
what rpm are you running in high gear?
166 hp at the rear axle just a gues but i would say 110 to 120 is all she's got.
what rpm are you running in high gear?
166 hp at the rear axle just a gues but i would say 110 to 120 is all she's got.
Thread Starter
Racer
Joined: Dec 2002
Posts: 400
Likes: 0
From: Spartanburg SC
Re: Poor Top-end Acceleration (377vette)
The rear should be a 3.08, and the speed I'm talking about is around 70 mph or so. I've never really taken it more than 90. I can't really tell you what rpm, b/c I strongly believe my tach is off, since it says 4k at 60 mph, and I know the rear gear isn't that high.
Drifting
Joined: Feb 2002
Posts: 1,906
Likes: 0
From: Berlin
Re: Poor Top-end Acceleration (Corey_68)
I'd imagine part of the problem is the stock L48 cam, great street/DD cam, but it's fote is NOT in the upper rpm band.
A simple thing is that the throttle cable brackets often get bent (usually at the pedal). Make sure that full throttle is actually full throttle.
Also check that your distributor is advancing properly, it has the right dwell, etc. Your carb could be set up improperly too.
Does the engine sound like its revving that high? Maybe your rear gear is really steep or your transmission is slipping (probably not). Its also fairly likely that you're not going 60 mph when the gauge says you are. The speedo is more commonly off than the tach is (people change gears without recalibrating etc). I said all that because an L48 does get sluggish much over ~4000/4500 rpm, but that shouldn't come until over 100 mph with 3.08's.
Thread Starter
Racer
Joined: Dec 2002
Posts: 400
Likes: 0
From: Spartanburg SC
Re: Poor Top-end Acceleration (aharte)
I'm fairly certain the rear gear isn't very steep, I can't even break the tires loose. The speedo is probably off too, but only by about 5 mph or so. The engine does sound like its revving as high as it should be though.
Racer
Joined: May 2003
Posts: 477
Likes: 0
From: KS
Re: Poor Top-end Acceleration (SCVetteGuy)
I read your mods; did you tune the new carb or just bolt it on? The engine may be running lean at WOT. If timing is correct and the air filter is new, rule that out. Was the fuel filter changed? Are the carb secondaries opening fully? Things to check out...
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Re: Poor Top-end Acceleration (Master Ho)
3.08 is not exactly gonna get you going quick, but I love the way that sucker runs at highway speeds. :)
[Modified by OHSIXX, 11:48 AM 5/24/2004]
[Modified by OHSIXX, 11:48 AM 5/24/2004]
[Modified by OHSIXX, 11:48 AM 5/24/2004]
[Modified by OHSIXX, 11:48 AM 5/24/2004]
