LT4 396 -- Finished
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Instructor
Joined: Oct 2000
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From: Austin, TX
LT4 396 -- Finished
I have not posted here in a while. I got the car back from Speed Demon about a month ago. Power is great -- see below.
The motor will settle any argument about a 256/262 solid cam being crazily large. Drivability is excellent.
[Modified by Charles Klein, 1:48 PM 4/16/2002]
The motor will settle any argument about a 256/262 solid cam being crazily large. Drivability is excellent.
[Modified by Charles Klein, 1:48 PM 4/16/2002]
Thread Starter
Instructor
Joined: Oct 2000
Posts: 221
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From: Austin, TX
Re: LT4 396 -- Finished (FoolCrzy)
Heads are GTP stage IIs with some extra porting work. Cam specs are 256/262, .629/.629 lift (with 1.5 rockers) with a 112 LSA. Intake was ported, 58mm TB, Headers, no cats, Power Effects exhaust system -- Sounds diabolical with the baffles open.
[Modified by Charles Klein, 2:35 PM 4/16/2002]
[Modified by Charles Klein, 2:35 PM 4/16/2002]
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From: College Station Tx
Re: LT4 396 -- Finished (Hammer)
I can attest to the drivability of the car! I delivered it to Charles and averaged 27-28mpg on the highway on the way up there. The car was an absolute dream to drive! As for power - well you can tell by the graph! The car just keeps pulling and pulling - it has a prodigous amount of low end, but when you get to the higher rpm's it feels almost like a boost car the way it pulls!
Congratulations on the great dyno numbers Charles!
edit:
Because the torque and hp are graphed on the same axis, but not scaled the same. If you look at the numbers they are *numerically* equivalent there, but do not cross since the scaling is different.
[Modified by ChrisB, 2:46 PM 4/16/2002]
Congratulations on the great dyno numbers Charles!
edit:
Why is HP & TQ crossing at 5800???? I thought they ALWAYS crossed at 5252 rpm's?
Because the torque and hp are graphed on the same axis, but not scaled the same. If you look at the numbers they are *numerically* equivalent there, but do not cross since the scaling is different.
[Modified by ChrisB, 2:46 PM 4/16/2002]
Le Mans Master
Joined: Jan 2000
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From: Thornton CO
Re: LT4 396 -- Finished (ChrisB)
Because the torque and hp are graphed on the same axis, but not scaled the same. If you look at the numbers they are *numerically* equivalent there, but do not cross since the scaling is different.
Le Mans Master
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From: San Francisco CA
Re: LT4 396 -- Finished (Charles Klein)
Love that dyno chart! :)
My shop just said my LT4 engine crank has .028" end play. Spec is .002 to .008", so we're talking
1. repair it (probably bearings),
2. replace with a rebuilt LT4 (it's still under extended drivetrain warranty), or
3. a new 383, which would end the warranty.
What made you choose 396 over 383? Anything in particular?
My shop just said my LT4 engine crank has .028" end play. Spec is .002 to .008", so we're talking
1. repair it (probably bearings),
2. replace with a rebuilt LT4 (it's still under extended drivetrain warranty), or
3. a new 383, which would end the warranty.
What made you choose 396 over 383? Anything in particular?
Thread Starter
Instructor
Joined: Oct 2000
Posts: 221
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From: Austin, TX
Re: LT4 396 -- Finished (A96LT4)
Love that dyno chart! :)
My shop just said my LT4 engine crank has .028" end play. Spec is .002 to .008", so we're talking
1. repair it (probably bearings),
2. replace with a rebuilt LT4 (it's still under extended drivetrain warranty), or
3. a new 383, which would end the warranty.
What made you choose 396 over 383? Anything in particular?
My shop just said my LT4 engine crank has .028" end play. Spec is .002 to .008", so we're talking
1. repair it (probably bearings),
2. replace with a rebuilt LT4 (it's still under extended drivetrain warranty), or
3. a new 383, which would end the warranty.
What made you choose 396 over 383? Anything in particular?
[Modified by Charles Klein, 3:18 PM 4/16/2002]
Melting Slicks
Joined: Apr 2000
Posts: 3,490
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From: Oviedo FL
Re: LT4 396 -- Finished (vettmanlt4)
Are those Rear Wheel numbers? I'm thinking on doing the MORE 396 LT1 package (I already have the top-end) and I believe they promise 490 - 534 at the flywheel. I don't think there choice of Cams is anywhere near that large however...
Mike
Mike
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From: Austin, TX
Re: LT4 396 -- Finished (luvmy92)
Are those Rear Wheel numbers? I'm thinking on doing the MORE 396 LT1 package (I already have the top-end) and I believe they promise 490 - 534 at the flywheel. I don't think there choice of Cams is anywhere near that large however...
Mike
Mike
It would be worthwhile to ask them what they expect to make at the rears. Using the popular figure of 15% power loss for a 6spd, 534 would be over 450 at the rears.
It would simplify things for tuners to talk only about rwhp to factor out disagreement about drivetrain loss. I have heard that Lingenfelter claims the loss is 17% for an LTx car. Of course the higher the claimed drivetrain loss, the higher the claims of delivered fly wheel hp.
[Modified by Charles Klein, 11:13 AM 4/17/2002]
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Re: LT4 396 -- Finished (Charles Klein)
Holy horsepower!! :eek:
Safety Car
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From: Toronto, Canada
Re: LT4 396 -- Finished (Charles Klein)
Congrats!:D
How much compression does the motor have, 11.5-12.1? I'm sure with good tuning a cam that size is streetable, does it surge at all below 2000 rpms?
Are you planning any 1/4 assaults?
How much compression does the motor have, 11.5-12.1? I'm sure with good tuning a cam that size is streetable, does it surge at all below 2000 rpms?
Are you planning any 1/4 assaults?