Best upper lower to reach 25 ilbs boost on 2.9 whipple

2004cobra615

sssvtsnake
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So what's the max boost people run safely on the stock motor. I heard don't go over 750rwhp and you should be good.

2004 Cobra 2.9 Whipple
 

03' White Snake

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There are many many people that have 80lbers and over 800rw on corn. I had 80lb injectors, I pulled them and switched to ID injectors and there were too many problems (across teh board not just me) with them at the time. So I talked to my tuner and he said do 80s. So I took the car apart again and got rid of the IDs and went back to the 80s and had plenty of room. Drives insanely well. Now of course at that time there were no ID1300s and if I end up doing my rebuild I probably will go back to IDs.


You can see the IDs already installed on my car before I had to pull them.

View attachment 1517035

I am running a 2.8h KB, on 80's and am just under 800 rwhp on e85. 22 psi, built motor with high CR. My base pressure is set at 55 psi, and I'm at 92-95% duty cycle on the injectors. -10 feed, -8 return, 2 465 pumps, Division x hat and rails.

So I agree, it can be done with 80's.
 

2004cobra615

sssvtsnake
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I am running a 2.8h KB, on 80's and am just under 800 rwhp on e85. 22 psi, built motor with high CR. My base pressure is set at 55 psi, and I'm at 92-95% duty cycle on the injectors. -10 feed, -8 return, 2 465 pumps, Division x hat and rails.

So I agree, it can be done with 80's.
Well I have the lethal budget kit and will be upgrading fuel pumps to the dual 465's

Looking forward to the switch this winter.i just got the A/F speed hut GUAGE and innovate lc2 module. I'll be installing those soon.

2004 Cobra 2.9 Whipple
 

Nadra

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So what's the max boost people run safely on the stock motor. I heard don't go over 750rwhp and you should be good.

2004 Cobra 2.9 Whipple
Regardless of where the boost comes from on a PD blower, you are fast approaching the sealing capabilities of the factory MLS head gaskets and head bolts at 24-25 psi.
 

cj428mach

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Regardless of where the boost comes from on a PD blower, you are fast approaching the sealing capabilities of the factory MLS head gaskets and head bolts at 24-25 psi.
I don't believe its a head gasket issue, its a bolt issue. The factory head gaskets are very good.
 

Nadra

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I don't believe its a head gasket issue, its a bolt issue. The factory head gaskets are very good.
Absolutely. Factory OEM style MLS head gaskets are light years ahead of where head gasket sealing technology used to be only a few short years ago. I am not an expert but I studied this area of engine integrity at length when I went thru my engine back in 2015. The conclusion I have come to accept as realistic (not necessarily 'fact' per se) is that boost from a PD blower should be capped at around 21-22 psi with the factory gaskets/head bolts. Boost from any turbo set up can be increased to around 26-28 psi. Beyond that...you are definitely rolling the dice with the factory set up; the head bolts are well beyond their engineered parameters.
 

klcmcse

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I agree. While possible(?), you will def be at the ragged edge on the 80s. ID1000s or 1300s are a better choice. And yeah, 25 psi is starting to really ask a lot from the OEM head bolts but more specifically the head gaskets. Most guys like you (us) who are shooting for 700ish try to stay around 21-22 psi on e85. At 25 psi from a screw blower, you are at or fast approaching the sealing capabilities of the std. MLS head gasket. You can add a little more boost from a turbo or TT setup and most would say factory head gaskets would survive but again, your weak link is still the factory head bolts. For reference, I have ARP2000 head studs in mine and I still keep it around 21 psi.
I need a of 80# injectors, If you or know some one. Thanks
 

gtmustang00

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2.9 Whipple here. Stock 3.5 upper and 4lb lower. 24ish lbs of boost. Stock intake with Accufab throttle body, Sct 2600 mass air, and K/N air filter. 1 7/8 long tubes, 3 inch x pipe, 2.5 inch catback. 700rwhp. I would think it would be 720rwhp or so but I guess not. 19 degrees timing I believe.
 

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