What Compression? Odin or 3.0L Whipple?

[GR1MBLE]

Long story short.. My engine blew after having a Roush supercharger on my stock 2020 GT after a month of it being on LOL.

My goal for the car is basically a street monster (lots of highway rolls and some digs), some track days (run mid 9s) and some cruising (drive once every two weeks to work, some mustang club cruises once a month).

I am very close to purchasing a level 2 short block (rated for 1200whp) from RPG and a 3.8l/3.0l Whipple or Odin Supercharger.

Where I live we do not have any e85 stations within a 5-hour radius. I eventually will be purchasing some e85 barrels which will be shipped to my house but for a majority of the time, I will be using 94.

I want to be around 700-750HP on pump gas and e85 900HP+ with room to grow. My shop is telling me to go with 9:1 compression, VMP told me 12:1 compression and Whipple said lower compression with the 3.8L Whipple if not get a 3.0L Whipple. Whipple said " 9:1 is low for a coyote but safer for pump gas. It would not be as ideal on E85 but will still help make more power."

Now my questions are:

1. What is the best compression for safety/reliability on pump gas for 700/750HP 900+ on e85
2. What do you think is better VMPs Odin or 3.8L/3.0L Whipple?

Thanks for any help in advance, it is greatly appreciated

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[80FoxCoupe]

This will be interesting!

 

[Wheysted]

There's already few threads about compression ;) worth a read

 

[LSchicago]

My vote is for 11:1 and a Procharger D1X.

 

[80FoxCoupe]

I wanna see the Whipple 3.8 on pump gas. Get it on video!!!

 

[RoadCone]

Compression isn’t the issue here. Lbs of Boost is. 3.8 you will never have low enough boost to run pump, unless you kill all timing. Your best bet is go with 11:1 or 12:1 compression and 3.0 Whipple. Pulley for 14 psi when on pump and turn it up when on E.

I wouldn’t run more than 800whp on pump.

 

[Basspro302]

Rpg told you 9:1?
3.8 is overkill for what you want to do. Are you mainly looking to run pump or e85? I wouldn’t pulley down more then the 3.875 on the gen5 3.0 on pump gas and 12:1.

 

[GR1MBLE]

Rpg told you 9:1?
3.8 is overkill for what you want to do. Are you mainly looking to run pump or e85? I wouldn’t pulley down more then the 3.875 on the gen5 3.0 on pump gas and 12:1.

The shop its at is telling me to order 9:1 shortblock from RPG as it would be safer on pump gas. Everyone else has told me 12:1.

Best bet then is stick with my stock compression (12:1) then order odin or 3.0l whipple.

If I am being completely honest I see myself running mostly 94 Pump but I will eventually be having two e85 barrels. The car is only driven for pleasure.

 

[GR1MBLE]

Compression isn’t the issue here. Lbs of Boost is. 3.8 you will never have low enough boost to run pump, unless you kill all timing. Your best bet is go with 11:1 or 12:1 compression and 3.0 Whipple. Pulley for 14 psi when on pump and turn it up when on E.

I wouldn’t run more than 800whp on pump.

3.0l or odin it is then with 12:1 compression. I am looking for around 750whp on pump and around 900 on E85

 

[80FoxCoupe]

@engineermike help this guy out will ya?

 

[GR1MBLE]

@engineermike help this guy out will ya?

I've been trying my best to learn about cars but I am still stupid. I am a IT Administrator nerd and this is going over my head lol. I am wanting 750ish on pump, 850/900 ish on e85 with room to grow in the future

 

[Decible]

Me personally after running several older boosted cars (without DI) my vote would be a 5.2 at 10:1 with a whipple or d1x. It’s half a point higher than the current GT500 and would give you the option to run pump safely and turn up the boost for e85. 9:5:1 and 10:1 would allow you to run as more timing than 11:1 or 12:1 for either fuel.

 

[vtknight]

I am building what you want - although staying stock engine this season. Gen V 3L build with all supporting mods (and an easy segway into a built motor) will make 700-730 whp depending on the dyno - I am guessing on pump - and 900ish on E85. The idea of the 3.8 as said above will likely destroy any pump gas options (even going the 10 rib option - which I did - would not allow the 20% OD lower because it is 15 psi minimum boost - so I had to stay stock lower). Start with that level and go from there. I am not a fan of the roots style blower.

 

[engineermike]

1. What is the best compression for safety/reliability on pump gas for 700/750HP 900+ on e85

This has been the subject of much debate, as alluded to by my fellow contributors. I will simply at this point state that you can no more pick a “best” compression ratio for pump gas AND E85 than you can pick a “best” compression ratio for gas AND diesel. Compression ratio is a big bag of compromises and highly dependent on the fuel being used. If you are building it for pump gas, it needs to be lower. If you are building it for E85, it can be higher.

 

[GR1MBLE]

This has been the subject of much debate, as alluded to by my fellow contributors. I will simply at this point state that you can no more pick a “best” compression ratio for pump gas AND E85 than you can pick a “best” compression ratio for gas AND diesel. Compression ratio is a big bag of compromises and highly dependent on the fuel being used. If you are building it for pump gas, it needs to be lower. If you are building it for E85, it can be higher.

Then I just need to find out if I want pump gas majority of the time and lower compression then or e85 majority of the time and 12:1 is fine.

If I had easier access to e85 I’d always be running it.

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