Advice on 4.6 500 hp build

Eric22ff

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Jan 20, 2018
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Hello everyone I’m looking for some advice. I have a 96 mustang gt that I built a couple years ago. It has forged pistons and rods, stage two cylinder heads by mhs and stage three camshafts. The car makes 290hp to the wheels at a 10:3:1 compression ratio and is mated to a 4r70w transmission with an fti 3400 converter. I’ve reached a point where I want more hp but my question is do I spend the money to upgrade what I have which would involve a forged crank, different pistons to lower the compression ratio, and a supercharger with appropriate camshaft. Or do I simply try to sell my car and start anew with a cobra mustang with a 4.6 dohc engine n/a. I don’t have the money to try and find a 03/04 termi. Overall my goal is 500 hp to the wheels. Let me know what people’s thoughts are and thank you.
 
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Do you still have the stock intake manifold? Not going to gain you much but it is restrictive. You have a good base. I wouldn't go internally again. Maybe a roots blower that would replace the intake and call it a day. Maybe push 6-8 lbs of boost. Turbo is another option. If you do go into the motor you can stroke it. So many options but they all cost money.
 
Do you still have the stock intake manifold? Not going to gain you much but it is restrictive. You have a good base. I wouldn't go internally again. Maybe a roots blower that would replace the intake and call it a day. Maybe push 6-8 lbs of boost. Turbo is another option. If you do go into the motor you can stroke it. So many options but they all cost money.
Negative it’s not the stock intake manifold it’s the edlebrock Jr Victor intake. I guess my biggest concerns are the crankshaft holding up, the compression ration and the fact that it has head bolts instead of studs. Do you think that running 8lbs of boost and proper cams would make 500whp while still being safe on the crankshaft and with that compression ratio?
 
I think the crankshaft would be fine as long as you stay under 425HP. I wouldn't push any more than 6 or 7 lbs on your set up now though but I'm not an expert in that area since I've never built a supercharged car. There have been people with that high compression that add a blower...just tune it to be safe. Maybe it would net you 100HP. There are blower cam grinds if that is the route you want to go but it's the expense that goes with a cam swap. Once at your goal of 500HP you would have to look at suspension upgrades. I blow the tires on mine at 325HP.

If you look at my set-up I am at 325HP (Mustang Dyno) at the wheels. That is with forged crank and big cams. I have the Victor Jr intake as well. Mine has 11.4:1 compression so I'm not planning on any boost. Yours is a little better suited as long as you don't get too crazy. You would need a good tune. Sounds like you have done a little research already. If you are set on 500 to the wheels then you know what you have to do.
 
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Ya sadly I also think the writing on the wall is there and that I’ll end up taking the engine out and doing a new build. Thanks for you advice on the matter though. Was wondering with regards to traction and getting that power to the wheels what have you done to better your suspension and how has it worked for you?
 
Ya sadly I also think the writing on the wall is there and that I’ll end up taking the engine out and doing a new build. Thanks for you advice on the matter though. Was wondering with regards to traction and getting that power to the wheels what have you done to better your suspension and how has it worked for you?
Nothing..that is the problem. :D I could probably do some traction bars and sticky tires and be OK. I don't go to the track anymre so I'm happy with a weekend driver at this point
 
Hello everyone I’m looking for some advice. I have a 96 mustang gt that I built a couple years ago. It has forged pistons and rods, stage two cylinder heads by mhs and stage three camshafts. The car makes 290hp to the wheels at a 10:3:1 compression ratio and is mated to a 4r70w transmission with an fti 3400 converter. I’ve reached a point where I want more hp but my question is do I spend the money to upgrade what I have which would involve a forged crank, different pistons to lower the compression ratio, and a supercharger with appropriate camshaft. Or do I simply try to sell my car and start anew with a cobra mustang with a 4.6 dohc engine n/a. I don’t have the money to try and find a 03/04 termi. Overall my goal is 500 hp to the wheels. Let me know what people’s thoughts are and thank you.
If you have e85 in your area, slapping on a blower with a tune will net you 500hp easily. The stock crank is a beast in these cars and wont need replaced until ike the 750hp range. Your entire setup with a blower would need a good tune.
 
With forged pistons and rods you are fine for 500 hp. Your compression is only slightly up which should be no problem for a tuner who knows what they are doing.

I would suggest a Vortech or prochager with A/A intercooler pushing 10-14 lbs of boost. (Prochager comes with intercooler but a kit can be purchased for the vortech) could also go the positive displacement supercharger route but the cost and labor time would be higher. A turbo will have much higher power potential but cost and install time goes up considerably.

I'm not familiar with procharger pulley sizes but with the Vortech a 3.33" pulley with a 10% overdrive crank pulley should get you 10-14psi through an intercooler with your engine combo using a 6 rib belt with no belt slippage. I would bet that gets you close to 500rwhp. If you want more boost/power you would need to switch to an 8 rib belt setup and smaller supercharger pulley to avoid belt slippage.

Then your problem is your trans. It will have to be built to handle that power. A supercharger is brutal on a auto trans.
 
I did forget to mention something. Your pistons and rings. For boost above 10psi your pistons should have a lower first ring groove and the rings should have a larger gap due to the higher heat levels. You would need to talk to who built your engine to find out what your setup is now.
 
I agree with sluggie and mods01gt above. Your stock crank is not the limiting factor. Don’t dig in to your motor yet. Buy a blower or turbo first, much cheaper than buying a new car- with your compression ratio and heads you should be easily in the mid 400 rwhp range with about 9psi on a safe 93 octane tune.

After that I would talk with your tuner to find which direction you want to go. Piston rings, forged crank shaft, and blower/turbo cams would optimize your engine setup but aren’t needed yet.