Wanting to up the boost but there is a catch

Blkkbgt

Well-Known Member
Established Member
Premium Member
Joined
Feb 3, 2011
Messages
3,078
Location
The land of commies and socialists!
it not a solid axle I don’t believe. Not really sure what tru trac means

When you list 31 spline axles it instantly makes me think you have a stick axle out back. I say this because the stock IRS half shafts are 31 spline inner and 28 spline outer and the stock solid 8.8 diff are 28 spline.

Truetrac is made by eaton and is a torque biasing diff with helical gears inside.
 

03' White Snake

Well-Known Member
Established Member
Joined
Feb 5, 2007
Messages
3,790
Location
Mass
Hopefully it is a manual Mach 1 engine, if not, you will need a forged crank too.

Bump compression ~9.0-9.5. Diamond pistons, Manley Rods, keep the kellog crank if it has one, ARP 2000 everything (rod bolts, side bolts, main bolts, head studs) Cometic head gaskets. Put in a full return fuel system (Prep for E85) then let it eat.

If you want to spend another 2k, go custom cams, springs ect.
 

Westtt80

New Member
Established Member
Joined
Sep 2, 2020
Messages
18
Location
Delaware
Hopefully it is a manual Mach 1 engine, if not, you will need a forged crank too.

Bump compression ~9.0-9.5. Diamond pistons, Manley Rods, keep the kellog crank if it has one, ARP 2000 everything (rod bolts, side bolts, main bolts, head studs) Cometic head gaskets. Put in a full return fuel system (Prep for E85) then let it eat.

If you want to spend another 2k, go custom cams, springs ect.

it is a manual Mach one motor.

Diamond pistons are better than Manley pistons?

I can get e85 relatively close to me also. Currently $2.06 a gallon
 

03' White Snake

Well-Known Member
Established Member
Joined
Feb 5, 2007
Messages
3,790
Location
Mass
it is a manual Mach one motor.

Diamond pistons are better than Manley pistons?

I can get e85 relatively close to me also. Currently $2.06 a gallon

Once you go corn, you won't ever want to go back.

Also, make sure you upgrade too the tool steel wrist pins.

I am a fan of Diamond Pistons, that is what I am running. I have never ran Manley pistons so I have no idea about them. I am running -5.2 cc dished Diamond pistons with 4V reliefs, Hard coat anodize tops and coated skirts. If I were to do it again, I'd skip the hard coat, they look great but are more race oriented for alcohol fuel, that was an extra $400 to have them coated. My calculated CR is around 10.3 . My car is on corn full time.
piston 1.JPG
piston 2.JPG
 
Last edited:

badcobra

It's Fast
Established Member
Joined
Aug 25, 2004
Messages
2,515
Location
Mpls/St Paul, MN
forged crank, rods, diamond pistons. e85 will be much more capable. Bore out to 302. 700 whp probably 12 to 15 pounds.
How do you 'bore out' to a 302? He would be much better off just leaving the block as close to stock bore as possible.

lower the better for high boost
That is old school thinking. New Coyotes come 12:1 compression, so there is no need for low compression. He could go at least 10:1 minimum and more depending on fuel.
 

mvk13

oooohhhhh Shiny!
Established Member
Joined
Jun 18, 2010
Messages
101
Location
Phoenix, AZ
A stroker rotating assembly can take it up to 5.0, but that's a lot of coin. Higher compression, corn, meth injection, a boost controller and a solid tune will get you to 700 easy.

Like the other folks have said, don't fear compression. I'm running 10.7:1

Cobras have knock sensors and can pull timing to control detonation. If you are really worried you can run. J&S Vampire to pull timing. John's anti detonation controller has progressive knock control and I don't regret the expense
 

badcobra

It's Fast
Established Member
Joined
Aug 25, 2004
Messages
2,515
Location
Mpls/St Paul, MN
Cobras have knock sensors and can pull timing to control detonation. If you are really worried you can run. J&S Vampire to pull timing. John's anti detonation controller has progressive knock control and I don't regret the expense
'03/04 Cobras do not have knock sensors. The J&S thing is neat, but you'd be best off going to a standalone before installing that and knock detection isn't needed running e85.
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,126
Location
Cali
The bright side to having the Mach engine is you have the aluminum block now. Instant 80lb weight saving. Or around there.

IMO you're not asking for much. Just remember not to go off your current pistons. The Machs came with 10.4 compression. But still, better rods and pistons with a stock forged crank then hit it with boost. You'll be able to make 700 with stock heads. You might want to look into porting the intake if it's a stock one. Or look into the Sullivan.

IMO, if you end up needing a crank for whatever reason go with a stroker. If you don't need one, stick with the stocker.

As for the rear axle, just look under the back of the car. It'll be pretty obvious if you have an SRA or IRS. Hell, can you see the tail pipes under the rear end?
 

Black02GT

*Not 2KBlackGT
Established Member
Joined
Dec 12, 2004
Messages
6,227
Location
NY
ideally I’d like to get to 700hp
This car is going to be a project and I want to do a lot of the work myself besides tuning.

Not to concerned about the axle. I have an enclosed trailer to get it to the track and will mainly take short trips close to home.

it not a solid axle I don’t believe. Not really sure what tru trac means

Solid axle as in "live axle", "stick axle", etc, no independent rear suspension. Tru-Trac is a gear based limited slip without clutches similar to the Torsen rears. I love my Trutrac or the street, drives like stock but puts the power down nice and even when you're on it.
 

Westtt80

New Member
Established Member
Joined
Sep 2, 2020
Messages
18
Location
Delaware
Once you go corn, you won't ever want to go back.

Also, make sure you upgrade too the tool steel wrist pins.

I am a fan of Diamond Pistons, that is what I am running. I have never ran Manley pistons so I have no idea about them. I am running -5.2 cc dished Diamond pistons with 4V reliefs, Hard coat anodize tops and coated skirts. If I were to do it again, I'd skip the hard coat, they look great but are more race oriented for alcohol fuel, that was an extra $400 to have them coated. My calculated CR is around 10.3 . My car is on corn full time.
View attachment 1662894 View attachment 1662895

4.6L Wiseco Pistons / K1 H-Beam Connecting Rod Combo

I was looking at this kit but not showing 5.2 dish
 

03' White Snake

Well-Known Member
Established Member
Joined
Feb 5, 2007
Messages
3,790
Location
Mass
-5.2 cc is what I am running. MHS offers a -6 cc dish.

Any # above 0 meaning 0.1+ means the piston is flat top or above The blocks deck. Depending on head gaskets you may run into interference issues.
 

95Cobra_Iowa

Active Member
Established Member
Joined
Jun 21, 2016
Messages
130
Location
Iowa
@badcobra knows what he's talking about. I haven't has as good of experience as others with e85. I've gone through 3 fuel pumps in a couple years with it so I switched back to 93.

That being said on 93 octane I inherited stock 8.5 compression with a twin turbo 2003 cobra with ported heads and I made 800hp on 18lbs on 93 octane. So with e85 or 93 octane it's more than possible.

A lot of guys have had success with Molnar power adder rods. Diamond pistons, gibtec, CP all make great stuff. With 700hp goal you have lots of options.
 

Blkkbgt

Well-Known Member
Established Member
Premium Member
Joined
Feb 3, 2011
Messages
3,078
Location
The land of commies and socialists!
How do you 'bore out' to a 302? He would be much better off just leaving the block as close to stock bore as possible.


That is old school thinking. New Coyotes come 12:1 compression, so there is no need for low compression. He could go at least 10:1 minimum and more depending on fuel.

Comparing the old style 4V terminator engine to the new coyote is not fair in regards to compression. Here is some reading on how the VVT I.E. phasing of the cams impacts dynamic compression ration and how it is used to allow these engines to run larger amounts of boost than most think is possible.

Boosted Coyote Engines using VVT

Increasing compression instead of boost?

Increasing CR vs boost pressure

Now can you run more compression? Yes but you need the proper fuel to go along with it and it's not as simple as using the coyote as an example.
 

95Cobra_Iowa

Active Member
Established Member
Joined
Jun 21, 2016
Messages
130
Location
Iowa
Comparing the old style 4V terminator engine to the new coyote is not fair in regards to compression. Here is some reading on how the VVT I.E. phasing of the cams impacts dynamic compression ration and how it is used to allow these engines to run larger amounts of boost than most think is possible.

Boosted Coyote Engines using VVT

Increasing compression instead of boost?

Increasing CR vs boost pressure

Now can you run more compression? Yes but you need the proper fuel to go along with it and it's not as simple as using the coyote as an example.

I agree with this to an extent. Compression is dependent upon what octane you're running.

The high horsepower coyote guys are locking their VVT out which eliminates that advantage. But at 11:1 without knock sensors on a stock 2003 computer that won't pull timing like the new coyote computers on 93 octane you'll be limited on how much boost you can run for sure.

I'm setup to run 15lbs on gate pressure up to 30lbs when I put c16 in the car and it seems to work well.

I do agree with your thought though, if you're running 93 octane versus e85 there's a point where the compression limits the boost or timing you can run safely
 

badcobra

It's Fast
Established Member
Joined
Aug 25, 2004
Messages
2,515
Location
Mpls/St Paul, MN
Knock sensors are not needed with e85. I've run 30+ lbs boost on pump e85 successfully for many years at 11:1 compression. My opinion stands, minimum 10:1 and nothing less.
 

stangfreak

Well-Known Member
Established Member
Joined
Jul 22, 2003
Messages
8,312
Location
new york
Knock sensors are not needed with e85. I've run 30+ lbs boost on pump e85 successfully for many years at 11:1 compression. My opinion stands, minimum 10:1 and nothing less.

At 10:1, could you use a fuel like ms109 or strictly e85?
 

Users who are viewing this thread



Top