03 cobra .how much boost will i have?

[nitrous408]

i got a 2.76 upper right now with 13/14 psi. boost. i was supposed to get a 6lb lower pulley ,but got a 9.0 inch or 8lb pulley,,my eaton off getting ported right now.how much boost will i have appx.? if i dont return it , cause iam getting the run around with rpm outlet again .i had a credit there if you remember correct.of $225.00 thats the only reason i order from them .dont use rpmoutlet for anything. so whats the boost?

 

[TheDukeOfEarl]

i got a 2.76 upper right now with 13/14 psi. boost. i was supposed to get a 6lb lower pulley ,but got a 9.0 inch or 8lb pulley,,my eaton off getting ported right now.how much boost will i have appx.? if i dont return it , cause iam getting the run around with rpm outlet again .i had a credit there if you remember correct.of $225.00 thats the only reason i order from them .dont use rpmoutlet for anything. so whats the boost?

You are going to try and run a 2.76 upper with a 8 lb lower on a Eaton? You will over spin the heck out of it. You will over spin all of your accesories. Are you building a dedicated car?

 

[Uncle Meat]

You are going to try and run a 2.76 upper with a 8 lb lower on a Eaton? You will over spin the heck out of it. You will over spin all of your accesories. Are you building a dedicated car?

Might as well say "Bye-Bye" to the blower. That combo is way too much for the Eaton, even if it has the latest porting. You will also need MAJOR fuel and cooling mods to go with a lower + upper combo of any type.

If this combo were actually installed the theoretical boost would be approximately 18.7 psi, and at engine redline you'd be spinning that HEATon at 22,491 RPM's ! Even if you went with a 6 lb lower the combo would potentially make 18 psi and blower RPM would be 21,431.

Most folks stick with a a 2.93 upper and a 2 lb or 4 lb lower on a ported Eaton. 16 psi is about the max you're going to safely and consistently extract from a ported Eaton and that's only if you have all the other supporting fuel & cooling mods.

U.M.

 

[nitrous408]

Might as well say "Bye-Bye" to the blower. That combo is way too much for the Eaton, even if it has the latest porting. You will also need MAJOR fuel and cooling mods to go with a lower + upper combo of any type.

If this combo were actually installed the theoretical boost would be approximately 18.7 psi, and at engine redline you'd be spinning that HEATon at 22,491 RPM's ! Even if you went with a 6 lb lower the combo would potentially make 18 psi and blower RPM would be 21,431.

Most folks stick with a a 2.93 upper and a 2 lb or 4 lb lower on a ported Eaton. 16 psi is about the max you're going to safely and consistently extract from a ported Eaton and that's only if you have all the other supporting fuel & cooling mods.

U.M.

a 9.0inch lower is how many psi of boost . i hear diff. things on diff web pages? if its a 6 instead of a 8lb pulley i will get a 3.00 upper.will this be ok? thanks

 

[Uncle Meat]

a 9.0inch lower is how many psi of boost . i hear diff. things on diff web pages? if its a 6 instead of a 8lb pulley i will get a 3.00 upper.will this be ok? thanks

Okay this is the definitive answer as far as size = boost when dealing with the lower pulley for an 03/04 Cobra.

DIA............BOOST
9.55 inches = 8lbs
9.10 inches = 6lbs
8.60 inches = 4lbs
8.00 inches = 2lbs

If in fact you have a 6lb lower you would want to run a 3.10 upper. That combo will give you 16.2lbs of boost which is pretty much at the very edge of performance for a ported Eaton.

Sure hope you have some 55 or 60lb injectors and all the other required fuel system mods plus as many additional engine cooling mods as possible to support this combo.

U.M.

 

[nitrous408]

well um .i got 14 psi before , heard that porting the eaton you lose boost right ? but how much? 2 psi? i dunno i wanted 16/17 max. i fuguired that a 6lb lower would but me there...again so the 9.0 pulley i got is a 6lb right? ..you think i should return it ...or just get a 3.00 upper with the 9.0. i was told the stock fuel system would be ehough also.by my dynoer. i not a 1/4 racer. just i quick take off person , i like the fell of tq.

 

[Uncle Meat]

well um .i got 14 psi before , heard that porting the eaton you lose boost right ? but how much? 2 psi? i dunno i wanted 16/17 max. i fuguired that a 6lb lower would but me there...again so the 9.0 pulley i got is a 6lb right? ..you think i should return it ...or just get a 3.00 upper with the 9.0. i was told the stock fuel system would be ehough also.by my dynoer. i not a 1/4 racer. just i quick take off person , i like the fell of tq.

I can tell you for 99.99% certainty that a ported Eaton at 16PSI will go lean very quickly when using the stock fuel system. The stock fuel injectors/pumps just can't keep up with the amount of fuel that combo is gonna require in order to stay safe. I'm sure the guys over at ModularFords will tell you the same thing.

Porting the Eaton will not cause a loss in boost, unless of course you had some hack job do the porting for you. The 9.10-inch lower is good for 6lbs as stated, couple that with a 3.10 upper and that will put you at approximately 16lbs of boost.

U.M.

 

[nitrous408]

I can tell you for 99.99% certainty that a ported Eaton at 16PSI will go lean very quickly when using the stock fuel system. The stock fuel injectors/pumps just can't keep up with the amount of fuel that combo is gonna require in order to stay safe. I'm sure the guys over at ModularFords will tell you the same thing.

Porting the Eaton will not cause a loss in boost, unless of course you had some hack job do the porting for you. The 9.10-inch lower is good for 6lbs as stated, couple that with a 3.10 upper and that will put you at approximately 16lbs of boost.

U.M.

ok heres what i got 3.00 upper and 9.0 lower....my problem is now. with my lower pulley kit the idler bracket with the 90mm pulley whan i rev it some under the hood , the belt comes off the front of the lower pulley by one groove? i had to shim out the lower pulley ring.about .125 to slove the problem.should i send this rpm outlet moto bluye crap back?.i havent gotting it dynoed tuned yet so i cant get on it yet ,, im afraid the belt will jump off. dunno? i have to drive 170 miles to dyno .i dont know how much bosst i will have , i dont want to change injectors or pumps. i hope i'll be ok.