engine ?s

[2004mw]

SO guys i just picked up a 03 cobra long block out of a wrecked termi...anywho its got 25k miles on it... My question is i wanna run my d1sc on it when i swap over i know the cpmpression is 8.5.1 should i go ahead ans swap the pistons and raise it some wanting to make about 600wheel

[Flash88]

you cant just swap pistons to a diffferent block. the Cobra pistons would be better than the machs factory pistons because their forged. and if i remember right cobras are 9:1 compression and not 8.5:1.

[2004mw]

im talking about the motor i just got i was thinking about swapping the pistons in it

[2004mw]

and its deff 8:5.1

[Flash88]

yea, your right it is 8.5:1 i was thinking of something else

the easy way is to just use the cobra motor, fully forged, maybe lower miles than your current motor, and block work.

[JoshMac]

Why would you raise compression on a engine built for boost that you are going to boost? There are bone stock cobra motors with the Hellraiser setup making in excess of 1000WHP. If you add compression you lower the amount of boost you can run without spending huge money.

[Stopsign32v]

More compression = better..........always

[shame302]

I'd leave it and pulley the snot out of it. Why take apart a good engine that's ready to go? I doubt you will notice a huge loss in low end due to lower compression but i've never driven a low compression car either.

[Stopsign32v]

Originally Posted by shame302

I'd leave it and pulley the snot out of it. Why take apart a good engine that's ready to go? I doubt you will notice a huge loss in low end due to lower compression but i've never driven a low compression car either.

Ohhhh yes you will. Low compression sucks ***. You want throttle response...ride in a high compression car.

[JoshMac]

Low or high a 600+ hp street car does the same thing everytime. He wants 600hp, I've rode in 500-725hp street mustangs, mostly cobras or other 4V powered cars. All did the same thing, whether turbo, roots/twin screw, or centrifugal. First and second on dr's was a spinfest. 1-3 sometimes 4th on street tires yeilded high pitched screaming as the blacktop was cooked. But period the only boosted cars I ride in and wonder where the bottom end is are hondas with .70 trims. But thats just me.

[Stopsign32v]

I can hook 1st gear in my Cobra with 629rwhp on a Mustang dyno through 4.30 gears with 275 DRs.

[JoshMac]

Originally Posted by Stopsign32v

I can hook 1st gear in my Cobra with 629rwhp on a Mustang dyno through 4.30 gears with 275 DRs.

On the street, with 32ish PSI, and no heat in the tires other than normal driving? I've been in bolt on GTs with 3.73s and DRs that spin in 1st. Last similar power car to that I was in was a 2.8KB car that made 638, on ET DR's, 1st and 2nd we were using both lanes for forward motion, that car had 3.55's.

[Stopsign32v]

Why would you have 32psi in a DR? My Mach 1 rolls around on DRs daily @ 25psi. Hooking is in the suspension, not tires.

I wouldn't build a motor to make less power because I couldn't hook up the power. LOL

[JoshMac]

Originally Posted by Stopsign32v

Why would you have 32psi in a DR? My Mach 1 rolls around on DRs daily @ 25psi. Hooking is in the suspension, not tires.

I wouldn't build a motor to make less power because I couldn't hook up the power. LOL

This friendly debate is pointless. You said throttle response is much better, I said no matter what the throttle response with power 600+ on the street yields the same results. The OP wants 600hp and felt he could not achieve it without changing the pistons to up the compression.

The baddest street machine I've been in is currently a T76 283CI 97 Saleen. The car before was a 711hp(on Snows) 4.6 T-Trim. The car had 4.10s and a Viper Spec T56 with this setup. At 90mph on 275 street tires the car would break loose. But that wasn't enough so it got to its current turbo setup. The car on stock saleen suspension, with 555DR's hooks in second with the snail spittin 21lbs with 3.55's again.

I never said don't build it cause you can't hook, but that I haven't been able to tell a difference with high"er" vs low compression boost engines other than the boost needed to reach the horsepower was less than that of the lower compression. In the OP's case, his stock long block will easily make and support 600hp with the breeze his D1SC provides. Why should he tear down a sound low mileage Cobra longblock when his goals are easily attainable?

And suspension is a great deal of hooking as well as a skilled driver, but put a street tire on your 629hp Cobra and let me know how it hooks. I would love to see your car in action, with 629 I'm sure its a hoot to drive. I have no doubts it will hook at the strip, but street use I just can't see it. Not in 1st with 4.30s.

[Stopsign32v]

Fastest car I've been in was a 1500rwhp Supra that....yep you guessed it, could hook up on DRs on the street from 2nd gear. Not sure what you and your friends are doing but it is easy to hook up as long as you use the right parts.

Sure he could make 600rwhp with low compression. Hell he could make 600rwhp on 7:1 compression. Would I personally change it to a higher compression? Yep... I'm just offering suggestions from my personal experience. ESPECIALLY if the car has a centri blower you want more torque. 10.1 would be idea IMO for a 600rwhp car with pump gas.

[Mach828]

I also agree that low compression sucks. That engine needs a turbo and a lot of boost to be impressive.

For a D1 setup, I would put some cobra cams in that engine (or something more aggressive), port the heads and your stock intake, and run more compression 10.1.

And then hit 600whp with low boost.

[Stopsign32v]

Take a 8.5 compression car, D1 and floor it in anything below 5,000rpms and tell me how much fun you are having.

[TRMach1]

Originally Posted by Stopsign32v

Take a 8.5 compression car, D1 and floor it in anything below 5,000rpms and tell me how much fun you are having.

That's what they make twin screw blowers for, my friend! I have a tremendous amount of fun with my 8.5 compression motor.

[blown03Mach1]

Originally Posted by Stopsign32v

Take a 8.5 compression car, D1 and floor it in anything below 5,000rpms and tell me how much fun you are having.

one word.



JUICE

[Scott McClure]

8.5:1 compression + D1 Procharger= a pig down low. Don't be afraid to raise the compression.

[littlemags]

Originally Posted by Scott McClure

8.5:1 compression + D1 Procharger= a pig down low. Don't be afraid to raise the compression.

always true scott

[blown03Mach1]

Originally Posted by Stopsign32v

Take a 8.5 compression car, D1 and floor it in anything below 5,000rpms and tell me how much fun you are having.

That is why you launch at 6k plus. No worries about the loss of 40 hp down low.

[na svt]

This thread went to crap.

Raising the dynamic compression ratio will by advancing the intake cams will increase tq and midrange power substantially. Set the cams at 108/116 and all will be well.

The piss poor cam stock cam timing is the only reason 4vs need steep gears.

[2004mw]

thanks guys for the input ive decided im gonna raise it to 10:1 cause i really do like how my stock mach motor runs good throttle

[2004mw]

Originally Posted by na svt

This thread went to ****.

Raising the dynamic compression ratio will by advancing the intake cams will increase tq and midrange power substantially. Set the cams at 108/116 and all will be well.

The piss poor cam stock cam timing is the only reason 4vs need steep gears.

so your saying just change my cam timing ?