Best boost compression ratio????

[Sketchy_Mach1]

Okay so I’m getting prepared to tear into my Mach 1 this winter and do a full rebuild. I’ve read different opinions on different forums about compression ratios. So I would like your opinion, is lower compression or higher compression better for boost. Btw I’m planing on using a Procharger or Vortech or a Whipple, something other than turbo.


Sent from my iPhone using the svtperformance.com mobile app

 

[Roots-type]

There's no way to answer that if we don't know what type of fuel you're going to feed it or what type of blower you want to use

 

[DSG2003Mach1]

^^^ what he said.

93 octane? e85? How much boost/end power numbers are important to have

 

[Sketchy_Mach1]

It’ll be a pump gas car, and just for now we’ll say Prochargers P1


Sent from my iPhone using svtperformance.com

 

[Sketchy_Mach1]

93 octane and I’m not 100% concerned on the numbers like if it made close to 400 I’d be happy


Sent from my iPhone using svtperformance.com

 

[DSG2003Mach1]

it would be difficult to make a number as low as 400 lol. The default 4" pulley will make 450+ @ 7k.

I ran 15psi on a 10:1 aluminator on 93 octane. It suffered an oiling failure and when rebuilt we went 9.5:1 since its on 93 octane most of the time. For pump gas and mild boost I would say 9.5-10

 

[Sketchy_Mach1]

Okay well that’s what I had in mind, I’ll be happier the higher the numbers are lol. The heads need to come off to get the valve guides fixed so I’m sending the heads to MHS to get them reworked and I figured while I’m in there I’ll go ahead and yank the motor to freshen up that tired 161k


Sent from my iPhone using svtperformance.com

 

[98 svt]

Okay well that’s what I had in mind, I’ll be happier the higher the numbers are lol. The heads need to come off to get the valve guides fixed so I’m sending the heads to MHS to get them reworked and I figured while I’m in there I’ll go ahead and yank the motor to freshen up that tired 161k


Sent from my iPhone using svtperformance.com

I sent my heads to MHS back in 2010. Just had my engine rebuilt (only 500 miles) over the summer and the builder said the heads were a shit show.
I wont be using them again.

 

[Roots-type]

P1 on 93--10:1
D1 on 93-- 9.5:1

What trans? What rear gear? Gearing along with compression can be extra critical to the fun factor of a centri blown car without a lot of cubes or boost

 

[Sketchy_Mach1]

4r70 with 3:73 or 4:10


Sent from my iPhone using svtperformance.com

 

[DSG2003Mach1]

I sent my heads to MHS back in 2010. Just had my engine rebuilt (only 500 miles) over the summer and the builder said the heads were a shit show.
I wont be using them again.

that was back when the old owner had it who did not use the parts he told me he used either. Its no owned by Jordan or someone like that who owns excessive motor sports, I've heard decent things about them

 

[Roots-type]

4r70 with 3:73 or 4:10

The factory auto is a 4r75w. I'm assuming this 4r70 is built then? If not, it'll need to be in order to take full advantage of the power curve you'll get with the centri. You really want to wring the piss out of them if you can. A stock auto will not be durable at 7k rpm. I'd lean towards a 4.10, maybe even a 4.30 depending...