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swap in Cobra long block with Eaton?

chief455

Member
Feb 8, 2014
21
0

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
For an Eaton swap i would rather have the 10.1 comp motor versus the 8.5 comp iron block motor, the 10.1 setup will give you a ton more torque on the street!

If you want a forged motor build a 10.1 aluminum 4.6l and enjoy your Eaton.


I disagree.
8.5:1 is way to go. And torque does not suffer at all..And you can beat the shit out of the car without risk of detonation.
 

Zack

4 Doors 4 Life
Mar 21, 2004
6,297
20
NW Indiana
The only reason torque won't suffer is because of the Eaton and so much low end torque, at 10.1 detonation wouldn't be a problem unless some bad 93 octane got in the mix

Its a horrible problem constantly, have you ever owned an eaton swap car with 10:1?
You cant run more than 12-13 degrees of timing and heat soaking pulls even more timing.

And the detonation isn't always at WOT. A lot of it is at part throttle in 3rd or 4th gear.
 

MOTOWN

S/C RWHP ADDICT!!!!!!!!!!!
Nov 29, 2012
35
0
ATLANTA
Its a horrible problem constantly, have you ever owned an eaton swap car with 10:1?
You cant run more than 12-13 degrees of timing and heat soaking pulls even more timing.

And the detonation isn't always at WOT. A lot of it is at part throttle in 3rd or 4th gear.

Nope never owned one, but swaped two for friends detonation was only a problem for them when they went below 93 octane, comes with owning a 10.1 4200+ lb car! Lol
 

MOTOWN

S/C RWHP ADDICT!!!!!!!!!!!
Nov 29, 2012
35
0
ATLANTA
The point im trying to make is simple:
You leave zero margin for error on a shortblock that is fundamentally weak from the get-go.

8.5:1 and positive displacement (with 93 octane) FTW

I completely understand your position on the comp issue, i just dont agree with it thats all, if you firmly believe in 8.5.1 comp w/Eaton blowers thats cool.

I my self would go 10.1 as i have many times in the past.
 

chief455

Member
Feb 8, 2014
21
0
thanks for airing compression ratio preferences, but I just want to know what fully forged shortblock will swap into my Marauder?
It seems a Cobra 4.6 is good candidate, just iron block weight and an 8 bolt flexplate needed?
Since I decided to boost the car, I'm going to build from the bottom up. I've learned my addiction problem, and am at one with it ;)
I have suffered the 'tuned for your compression/octane' detonation blues, and rebuilt the damaged motor with less compression for safety margin. On a street car, that is much more important than a high power number to me.
Heck, after 450rwhp, it's all too much for the street anyway!
 

chief455

Member
Feb 8, 2014
21
0
I agree 450HP is fun on the street. The best thing about modding a Marauder is we drive a rare breed. Having boost is just more icing on the cake.

Be sure to start a thread when you start turning wrenches

WILL DO.
I'M ON THE FENCE ABOUT USING MY STOCK MM ENGINE NOW, SEVERAL GUYS ARE INTO 12'S WITH THEM, JUST EATON, OTHERWISE STOCK - THAT WOULD BE LOWEST COST FUN FACTOR..sorry, caps lock
 

chief455

Member
Feb 8, 2014
21
0
What's wrong with your stock engine? I SC'ed mine after 100,000mi without any worries. I always fixed any mechanical issues and it's never ran hot.

nothing - healthy 82,000 mile car with rebuild trans and 4.10

I had a expensive detonation from going lean happen on a different car, showed me 2 seconds of low fuel supply hammers the pistons dead, and it snowballs from there.:roflpicard:
I'm paranoid, period.
After reading Lidio's 2003 success with Trilogy and over 10lb boost, and other current members getting 12's out of stock motors with Eaton only - I'm leaning back toward using my engine as is.
Scary for me is tuning - after the install, how do I run the car on my current N/A tune? trailer it to a dyno tuner?
 

chief455

Member
Feb 8, 2014
21
0
An eaton swap with 10psi and no headers makes for a really fun car.
There is not a big 'seat of the pants' difference between 420rwhp and 475rwhp.

bingo.
My Procharged T/A dynoed 580rwhp by previous owner, and though fast, it never felt right, and detonated.
Since full rebuild, dyno tuned conservative 500rwhp = ridiculous tire buning machine with zero scary timing in my brain.
 

musclemerc

Addict
Jan 6, 2010
554
0
nothing - healthy 82,000 mile car with rebuild trans and 4.10

I had a expensive detonation from going lean happen on a different car, showed me 2 seconds of low fuel supply hammers the pistons dead, and it snowballs from there.:roflpicard:
I'm paranoid, period.
After reading Lidio's 2003 success with Trilogy and over 10lb boost, and other current members getting 12's out of stock motors with Eaton only - I'm leaning back toward using my engine as is.
Scary for me is tuning - after the install, how do I run the car on my current N/A tune? trailer it to a dyno tuner?

Run it like it is. I don't think you will have any issues with your current milage. Just remember to not go any bigger then a 3.0 pully on the Eaton you got. Any more than 13lbs of boost and all bets are off on your stock block.
 
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