[pimpdout98gt]

i know this has been an ongoing conversation with forums all over the net. i know that my heads are the limiting factor (in my setup), but i recently had my engine redone and didn't bother to do anything to my heads except have my mechanic smooth them out a little bit. i do now have comp cams XE268H-14 installed and put new valves springs in. by the way i have a 98 GT. my ultimate goal is to exceed 400 hp at the rear wheels. my last dyno tune netted 370 rwhp and 430 rwtq and that was with a shitty sniper tune installed and plenty of detonation up top, no offense to sniper but my car needs more in depth tuning. i know stock 96-98 GT's don't put out alot of horsepower in the first place, so i know i am asking for alot from my car. but if i could clear 400 rwhp without changing my heads i would be stoked. here is a list of my (power) mods; let me know what you guys think i should or could do to reach my goals:


1998 Ford Mustang GT

currently approximately 2,000 miles on rebuilt engine
JE forged flattop pistons (compression bump to approx. 10:5 or 10:7)
Manley forged h-beams connecting rods
Comp Cams XE268H-14
Comp Cams valve springs
Detriot Speedworks P.I. intake kit
Trickflow plenum
BBK 75mm throttle body
Fluidyne 2 core radiator
BBK 1 5/8 long tube headers
VRS offroad x-pipe
Magnaflow catback
Ford Racing 3.73 gears
Paxton Novi 2000 w/2.75" pulley & Innovators West 10% overdrive crank pulley producing 15-20 p.s.i. with belt slip
Paxton intercooler
PMAS blow through meter
Ford Racing 42 lbs. fuel injectors
Kenne Bell boost a pump
Kenne Bell boost a spark
Ford Racing aluminum driveshaft
Vortech Maxflow bypass valve
Vortech 255 lph intank fuel pump

i'm currently considering converting back to draw through with a SCT big air maf and 60 lbs. injectors and also changing out my catback and midpipe with an American Thunder and BBK offroad h-pipe.

but i just need you guys advice and input on whether or not i will be able to surpass 400 rwhp with the mods i currently have. any and all advice is appreciated. thank you

[330CubeGt]

Spend $400 Get a cheep kit and Put a 50 shot, Get a tune and be done.

[ReverendDexter]

Use a lighter wheel/tire combo if it's available. Swap to fully synthetic fluid in your transmission and differential. Up the boost another couple pounds. Remove the A/C and/or power steering. Go to an electric water pump.

[MikeD05GT]

put comp 270's in it.. or a crower blower cam... and +100 to stewart water pump...

[G.T. Rags]

do u still have an NPI intake manifold? If so, then that right there is whats holding u back

[pimpdout98gt]

well, those dyno numbers i referred to earlier, i made them on on 6.1 p.s.i. i know that i was putting out 15 p.s.i. before the dyno because i went out and tested so i don't know why the dyno tech stopped at 6.1 p.s.i. maybe because on air/fuel or too much timing with detonation. i do have the p.i. intake manifold. i really don't want to remove my a/c. i thought about it but my car is a daily driver. i thought about the waterpump. cams aren't that extensive but i really hate to tear back into my engine since it was done before. i felt that i shouldv'e done it right the first time. i am gonna try more boost and a professional tune this time. lat dyno i had my sniper tune in there and i input it myself.

[330CubeGt]

Originally Posted by 96GTRagTop do u still have an NPI intake manifold? If so, then that right there is whats holding u back

Originally Posted by pimpdout98gt Detriot Speedworks P.I. intake kit

.

[330CubeGt]

Originally Posted by pimpdout98gt well, those dyno numbers i referred to earlier, i made them on on 6.1 p.s.i. i know that i was putting out 15 p.s.i. before the dyno because i went out and tested so i don't know why the dyno tech stopped at 6.1 p.s.i. maybe because on air/fuel or too much timing with detonation. i do have the p.i. intake manifold. i really don't want to remove my a/c. i thought about it but my car is a daily driver. i thought about the waterpump. cams aren't that extensive but i really hate to tear back into my engine since it was done before. i felt that i shouldv'e done it right the first time. i am gonna try more boost and a professional tune this time. lat dyno i had my sniper tune in there and i input it myself.

I would say a water pump and a REAL tune should put you right there.
A good tune can make a lot of a diffrence.

[G.T. Rags]

mybad, didn't see that.......

[pimpdout98gt]

so do you guys really believe that an electric water pump will help me reach my goal? even if i put a 50 shot of nitrous on my car don't you think my heads would hold me back? i am most likely gonna convert back to draw through and get a professional tune done. i am currently deployed right now. alot of my mods i haven't installed yet, like the Kenne Bell stuff, the exhaust and draw through maf and 60's. once i return i will install everything i plan to use and get a professional tune.

[ReverendDexter]

Everything I mentioned before outside of upping the boost were things that reduce the amount of parasitic loss, rather than increasing the total power output. So you're heads will have *nothing* to do from power gains seen there.

[MikeD05GT]

aluminum drive shaft

[FineLineMtrSprts]

I dont trust electric water pumps on the street. I know LOTS do but ive seen 3 fail and toast an engine. Get your heads ported and polished and some real blower spec cams. Also am i reading this right, you're running 15lbs of boost with 10.5+ to 1 compression..umm why? But anyway..hit another dyno shop that works with SCT, which is my choice but some like Diablo.

[ModMustang97GT]

Your numbers don't pan out. Flat top pistons are going to put you alot closet to 11.5 or 12:1 not 10.7 And your boost numbers. 15-20psi. Youd need a new pulley and belt to even get the supercharger to keep spinning anywhere near those numbers. And if you were pushing 10.5:1 and running 15-20 psi. You would be having to run 113 octane fuel, 60 psi injectors and youd be closer to 600rwhp. Your heads are a limiting factor, but when you add FI to the mix, they don't really matter. More boost equals more power. Doesn't matter if you have a totally stock engine. With 15 psi you should be well over 500rwhp. Think about it, do your research, the mods list you posted makes not sense. You never do flat top pistons with FI, were you not planning to go FI?

The recomended compression ratio is 8.5 to 1. You are running closer to 10.5 to one. Stock 99+ compression. The 10.5 to 1 is 25% more compression than recomended meaning you would want less boost to get the same power. You would want like 6psi to get the equivalent of 9 or 10 psi of power on a normal engine. Plus, for each additional compression point, you are making your amount of boost possible go down by increasing the charge temp significantly. You are losing tune ability. With flat tops and 11:1 compression, the tuner would be trying to keep your engine together let alone tuning it to make maximum power. Do some research man. Your car doesn't make sense.

[pimpdout98gt]

you know what? you are right. my car dosen't make sense. i didn't plan my build. i just bought alot of new parts and had my engine put together. what you say makes alot of sense. i really don't know exactly what my compression is. i did find an online compression calculator and i came up with with 10:8.1 as an approximate number. i have been currently concidering removing my blower and going n/a. i have just gotten use to the boost and prestige of the Novi 2000. i'm sure you guys understand that. well performing a rebuild of my engine is completely out of the question now, as far as getting dished pistons or porting my heads. i have a newborn and a mortgage now plus my wife keeps me from going overboard. i've had my car sine 2002 and i calculate that i have dumped over 40 grand into it so i'm at my wits end. so i pretty much have to deal with what i got. should i just run the stock Novi pulley or should i remove the supercharger all togther and enjoy my setup n/a. what do you guys think?





__________________

[MikeD05GT]

i would back the boost down and no questions asked get that thing to a real tuner ASAP...

[ModMustang97GT]

With 8psi of boost. You will have no problems with the pulley. And with a competant tuner, you should be able to get some real power out. The flat top pistons is what confuses me, your compression ratio should be really high. A good tuner or machinist would be able to tell you pretty quick with a compression tester or a quick look at your parts list.

A good tune with 8 psi and your compression being 10.8:1 would put you at ~460 rwhp. You should have no problem breaking 400 rwhp. Get to a good tuner and have him take a crack at it. They should be able to tell you all you ever wanted to know.

[acidtonic]

I hate to say it since it seems this isnt an option for you but remember a 4.6 4valve can reach 400rwhp NA. With race gas and other things they've gotten as high as 600+rwhp but thats not what an average joe would get or even close.

Staying NA is usually more expensive than FI but in general you have less going on and more peace of mind.

I'd say to keep your current motor in one piece you will need a lower compression rebuild otherwise remove the blower or significantly lower the boost and get a tune. It wont last with that setup let alone the detonation you already see.

If I were you I'd find a 4valve out of a wrecked Cobra or Lincoln and use that then sell your current block. Ported C heads, ported intake, valve job, cams, tune and you will be singing at least 400rwhp with a larger power band.

[HBK_2007]

Originally Posted by acidtonic If I were you I'd find a 4valve out of a wrecked Cobra or Lincoln and use that then sell your current block. Ported C heads, ported intake, valve job, cams, tune and you will be singing at least 400rwhp with a larger power band.

thats my plan

[2002BLGT]

PMed about the tune , timing is going to be tricky with close to 10.8 compression and boost