Considering an Eaton swap on my '04 Mach 1

[sutyak]

... to go with the big single turbo.
I'd like to make up for the lack of low end torque on this setup with an Eaton or other smaller supercharger. Something that will still fit under the hood scoop. I enjoy going off-script a bit with my builds and getting into areas that other people shy away from. I would like some advice, though if anyone has some input. Physically, I'm sure with some massaging and fabrication I can make everything fit. The primary concern I have is would the supercharger actually become a restriction in the upper RPMs, where the big turbo will really shine?
Ultimately I doubt I'll stick with the single turbo by itself because I don't enjoy turbo lag. It currently has a single Precision 7675. (yes George I know you have 2)
To tackle this lag, I'm either going to 1) add an Eaton 2) smaller 6675 turbo, or 3) ditch the turbo completely and go with a KB or Whipple and hope I can keep the Mach 1 hood.

All comments welcome. Whichever direction I go I'll have a build thread.

[Mark Aubele]

When does it start making boost? Can't imagine it being that bad. Can't imagine the weight, complexity, and heat from two separate power adders.

[TooFast98Cobra]

Compound boost . Why not throw in some spray and cool things down too. Good luck with your build . Sounds fun.

[Tom]

compound boost would be a cool build to see

I would go with the 6870 gen2 cea bb if you stay pte.

[sutyak]

When does it start making boost? Can't imagine it being that bad. Can't imagine the weight, complexity, and heat from two separate power adders.

The complexity is part of what interests me. :)

Here is the current dyno graph provided by the seller. It makes full boost around 5-5.5K RPM according to the graph, and it certainly feels like it when driving it. The PTE 7675 is supposed to be a 1200hp turbo, so there is lot of power left on the table. A smaller turbo would likely meet my needs, but honestly there is part of me that wants the whine of the blower and the instant torque.

This 5K RPM spool dilemma is exactly why I dropped back in size turbos on my Focus, and the car is much more fun to drive now, even if it doesn't make as much power.

[no1sirbutler]

The eaton will become a restriction and can actually cause a loss of total power. It also doubles the maintenance on the car. The heat from the turbo will cause the belt to stretch easier....also have to take in consideration of turbo placemtn in the car. If the turbo is behind the radiator will you have enough room for the belt system?

and don't forget tuning.....not sure who you use but when I was considering this with mine the tuners I talked to said its a nightmare.

Anyway good old luck and keep us posted

[sutyak]

The eaton will become a restriction and can actually cause a loss of total power. It also doubles the maintenance on the car. The heat from the turbo will cause the belt to stretch easier....also have to take in consideration of turbo placemtn in the car. If the turbo is behind the radiator will you have enough room for the belt system?

and don't forget tuning.....not sure who you use but when I was considering this with mine the tuners I talked to said its a nightmare.

Anyway good old luck and keep us posted

I didn't consider the belt stretch issue. That's a great point.
I'd do the tuning myself. The company who did the current tune is supposed to send me the current tune file. From there I'll take over with the SCT pro racer software.

[SlowSix]

I'd just go smaller Turbo.
Compound boost seems to be one of those things that is cool in theory but not a great idea in real life.

[sutyak]

I'd just go smaller Turbo.
Compound boost seems to be one of those things that is cool in theory but not a great idea in real life.

That's what I'm leaning towards at the moment unless someone wants to swap me my entire turbo setup for a KB or Whipple.

[SlowSix]

What a/r is that Turbo ?

[sutyak]

What a/r is that Turbo ?

Turbine or compressor housing? I'll check later today when I'm in the garage.

Exhaust AR is .96. Dropping down to a .68 might help a lot.

[no1sirbutler]

I didn't consider the belt stretch issue. That's a great point.
I'd do the tuning myself. The company who did the current tune is supposed to send me the current tune file. From there I'll take over with the SCT pro racer software.

Good luck with the tuning with compound boost. I spent a lot of time talking to Ken Bjonnes about this. He said the end result was not worth the headaches with all the heat and drive ability aspects. He said picking one or the other was better

[Martin0660]

understand your AR's and you can optimize that much better ... Also drive a small displacement turbo car like a turbo car and enjoy life

[TooFast98Cobra]

Is the engine built for boost? Bottom end etc?

[sutyak]

Is the engine built for boost? Bottom end etc?

Yes. Manley rods and CP pistons I believe. 8.5:1 CR. I'd have gone higher compression if I built it. The lower compression pistons just accentuate the lack of low end power.

[SlowSix]

understand your AR's and you can optimize that much better ... Also drive a small displacement turbo car like a turbo car and enjoy life

Yup.
I'd go to a .81 ar exhaust housing and moar rpms

[JeffreyCole]

Compound boost has been successfully done in the DSM world, but it was with two different sized turbochargers. I think the extra heat provided by the Eaton would be tough to combat, along with difficulties in packaging.

If you got a smaller turbo and used it in conjunction with the larger turbo, I think you would have a much easier time tuning it.

[sutyak]

Compound boost has been successfully done in the DSM world, but it was with two different sized turbochargers. I think the extra heat provided by the Eaton would be tough to combat, along with difficulties in packaging.

If you got a smaller turbo and used it in conjunction with the larger turbo, I think you would have a much easier time tuning it.

I considered compound turbos. I still have that 3082R which would work great. Space is an issue, though.

[JeffreyCole]

I considered compound turbos. I still have that 3082R which would work great. Space is an issue, though.

Personally, I think a turbo that size is probably a bit too small for a 4.6L engine, especially on a T3 footprint. If you could get a big fat T4 hotside, you might be OK, but I would probably want to stick to something in the 35R size as the small turbo. a 3582R would probably light off really quick, and rip the top end with that big ol PTE on there.

[sutyak]

Personally, I think a turbo that size is probably a bit too small for a 4.6L engine, especially on a T3 footprint. If you could get a big fat T4 hotside, you might be OK, but I would probably want to stick to something in the 35R size as the small turbo. a 3582R would probably light off really quick, and rip the top end with that big ol PTE on there.

No not the 3082 by itself, for compounding.