new engine low on power....

[Keith 5.0]

I recently installed my new engine and got it back on the road. Upon taking it for a test drive, I realized that it doesn't have any low end torque to it. It doesn't really pick up on power until 3000 rpms. Any idea as to what it might be?

My car consists of the following...

teksid block, standard bore
JE flat top pistons (11:1 CR)
Scat 4340 rods
stock unported heads/ stock cams/ stock unported intake
LT's & Prochamber
4.10 gears/ solid axle

 

[BlueStripe]

It's a 4v.

 

[cobra2798]

99'-01' 4v have no low end torque, sucks but its true. If your making good power around 3000k then your doing good. I think most dont start to get going good until after 4k.

 

[99COBRA2881]

99'-01' 4v have no low end torque, sucks but its true. If your making good power around 3000k then your doing good. I think most dont start to get going good until after 4k.

4v or not compression makes torque the car should have more lowend than a stock c/r cobra.
Other than compression ratio the engines mostly stock, if you had ported heads, intake, and 03 cobra cams listed then Id think theres a problem. When in doubt get it dynoed w/ an air fuel reading.

 

[Keith 5.0]

I know it's a 4V, but I drove the car for 2 months before it took a dump on me, I know it wasn't this low on power before.

I forgot to mention that the car's not tuned, which is what I'm hoping it is. I knew I'd need a tune before taking it on a long drive, I just figured I'd be able to take it around the block and see how it drove.

I put 111 octane in the tank mixed with 91, just to ensure I wouldn't do any damage while taking it around the block. I mixed around 5 gal. of 111 with about 4 gal. of 91

 

[VirtualSVT]

Oh..if its not tuned that can have a lot to do with it.

isn't 111 leaded?

 

[Keith 5.0]

Oh..if its not tuned that can have a lot to do with it.

isn't 111 leaded?

no, it an unleaded gas :rolling:

 

[duane v]

Way too much octane for 11.1 CPR...the most youll need is 100..If they still had 93 octane in CA, I would try to run that octane with my 11.1 pistons...

Give it some time, youre probably used to the the torque of the 5.0 that you drive around...DA snake boy!!!

 

[VenomousSVT]

get it to a dyno, changing the compression/internals on mine made my tune all crazy as well. Mine felt like crap after the rebuild but after tuning it got back to the way it should feel

 

[Wicked01]

Tune..

 

[wallie40]

hey kieth glad to see that miz got your car up and running. He did a great job on my live axle.

-pAul

 

[4vBlewDevil]

yeah my buddy swapped out his pistons in his 01 4v to 10.5:1 and he had the same problem. once he got his cai and had it tuned it ran way diff. the computer can compensate for small changes in fuel air spark but jumping from 9.85:1 to 11:1 is a big change for the computer. if it still runs like crap after having it tuned the only other thing i can think of its its s new motor and if its not a factory spec motor it may take some times to wear in. id say 3-5k miles to really feel where it should.

 

[CY98Cobra]

You all think a 99-01 has no low-end, try a b headed 96-98. No power until 3000, 4000 it really kicks in.

 

[VirtualSVT]

You all think a 99-01 has no low-end, try a b headed 96-98. No power until 3000, 4000 it really kicks in.

Wouldn't that be Vtak?

 

[cobraracer46]

The rings may need more time to seat. Additionally, you may want to plug in a scanner and see if all the computer sensors have the correct values.

 

[Quadcammer]

the rings seat in the first 30 minutes of run time.

flat top pistons get you to about 10.5cr, not 11 to 1.

basically, the extra octane ain't helping and yeah, its a 4v.

 

[Keith 5.0]

the rings seat in the first 30 minutes of run time.

flat top pistons get you to about 10.5cr, not 11 to 1.

basically, the extra octane ain't helping and yeah, its a 4v.

I realize these pistons bring the CR up to 10.5:1, but the machine shop milled a little off the heads and the block. My engine builder calculated my CR and it's 11:1

 

[bigpapa]

Becasue if the increase in compression you are rich and that is causing you to be down on power. Go get it tuned.

 

[4vBlewDevil]

yeah it shouldnt cost you much to get it tuned, a pass on the dyno with a wideband hooked up will let you know where you stand, and if you have a handheld tuner like me you dont have to pay them to add more fuel or spark, i got like 30 wrh from just adding a bit to my wot fuel table...and im almost certain that you will gain a good amout of power when your AF ratio is where it should be.

 

[Quadcammer]

I realize these pistons bring the CR up to 10.5:1, but the machine shop milled a little off the heads and the block. My engine builder calculated my CR and it's 11:1

in that case, its possible your cam timing is off.