Compression ratio/gearing for a D1SC Mach 1?

[Skylar]

I'm in the process of making a list of everything I'll need for a build. I'm planning on going forged internals and was wondering what compression is suggested if I'm going to be adding a D1SC? Also, the previous owner changed the gears to 3.27's. He said it was because he was planning on supercharging it, but never did. I've got some 3.73's I never got put in. Would it be better to keep the 3.27's or go 3.73's? It's an '04 automatic with around 86k miles. I'm wanting to get the highest #'s I can without pushing the motor.
Thanks in advance!

 

[MackDombles]

I'm in on this. Doing the same boosting a Mach engine. I've heard 10psi Max on oem bottom end.
I'll wait here for the pros to answer though.

 

[SuperMach1]

What type of fuel will you be using and will this car be mainly on the track or Roll Racing? My car is procharged with a P1 and 410 gears. I ran a 10.9 at the track but I do more roll racing and I'm going to be switching to 3:55

 

[Skylar]

What type of fuel will you be using and will this car be mainly on the track or Roll Racing? My car is procharged with a P1 and 410 gears. I ran a 10.9 at the track but I do more roll racing and I'm going to be switching to 3:55

I want to keep it on 93 octane. I want it to behave on the street and be super reliable. My main goal is longevity at as high of #'s as I can get. I test drove a mach 1 with a procharger & 4.10's not long ago. It was really quick, but it was a test drive so I didn't really get above 50.

 

[DSG2003Mach1]

I'm at ~15psi on a D1, we went 9.5:1 since it's on 93 most of the time. I currently have 4.10s with a wide ratio magnum t56 and it rolls the **** out but it's too much gear. The hearing was picked when 550ish was the goal, overshot that by a lot lol

 

[SuperMach1]

If you're going to build it I would go with a 10 to 1 compression. If you're going to boost with the stock block I'd stay around 430-460 hp. 3.73s should be good either way

 

[DSG2003Mach1]

I'd say it also depends on how much boost you intend to make or if you wanna limit it with a waste gate on pump. The tuning window/margin for error starts getting small (it's doable though)

 

[sutyak]

Unless you're trying to perfectly RPM match your 1/4 mile trap speed the gears will be completely personal preference.
I say don't change the gears until the d1sc is on and you get a good feel for the car with the new power.

 

[Skylar]

Thanks for the info, guys. I'm going to build the motor as strong as I can using the stock block. With forged internals, it should be able to hold pretty high boost so I was thinking either 8.5:1 or 9:1. I'm wanting to hit at least 600rwhp

 

[DSG2003Mach1]

i would not go that low with a centrifugal, car will be an absolute dog out of boost

 

[Skylar]

For Intercooled ProCharger EFI/TPI applications with compression ratios less than 9.5:1, boost levels of 14-17 psi can be safely run with full timing on pump gas, and will produce horsepower gains of 75-100% (depending upon the boost level and the motor specifications).

^ That's from Procharger's website. That's what was making me want to go lower compression. 8.5 does seem too low. I'm leaning toward 9.3:1. (I meant to say 9.3:1, not 9:1 in my last comment ^^)

 

[DSG2003Mach1]

i need to quit being a lazy bastard and go make a quick pull in mexico to send to the tuner then go get new dyno numbers. Previous motor was 10:1 this one is 9.5:1, curious to see the difference

 

[Roots-type]

10 to 1 comp. Even more if you can feed it corn.

Gearing all depends on what the car is being setup to do. The 3.73s will be better than 3.27s either way though.

 

[sutyak]

Definitely 9.5:1 or 10:1. I have 8.5:1 with my turbo (I bought it that way), but if I have to do it again I'll go closer to 10:1 and use meth injection if needed. No E85 near me.

 

[Skylar]

I'm thinking 9.3:1 is going to be best for my build. Procharger recommends below 9.5 for intercooled prochargers on pump gas running higher boost and that's exactly what I'm planning on doing.

 

[SuperMach1]

In that case I would go with 4.10 or 4.30s.

 

[DSG2003Mach1]

In that case I would go with 4.10 or 4.30s.

eh, depending on final power level the problem with that is running out of gear in the 1/4. I need to do some research still to figure out what size tire would keep me from running out of RPM in 4th by the end of the 1/4.

 

[SLOW32V]

Well, I have 4.30s and with a 26" tire I'm running through the 1/4 at 6800-7000rpm. Thats with a 5spd though not sure if that helps or not. 471rwtq 386rwhp 100shot

Sent from my XT1254 using the svtperformance.com mobile app