Allen2001GT

Got the car retuned tonight. left it with 407 hp and 468 tq at 8lbs. the tune is a little rich so i can put my 10lb spring in and run it like that just didn't have it with me at the time. tuner (Frank at PSI in pa) said it should easily be making over 420 hp and over 500 tq. i'll post up the dyno sheet either tomorrow or saturday morning. going to take it to the track tomorrow night to see how it runs especially since i haven't run it with the refreshed reend and 3.55's in it.

p.s. this is on stock block btw.

contentsunderpressur

Great numbers for the boost your running. You shouldn't have any problems with the stock bottom end holding 407 hp. Keep us posted on what you run at the track.

oxfordgt

Bring a trailor to the track with you

livefast1

nice numbers do you have a mods list?

this is my opinion on why people have such trouble with turbo 4.6s. the valve springs in the 4.6 are relatively light and when a restriction is placed in the exhaust track backpressure is produced. at higher rpms this backpressure can float the valves. not many people know this but floating the valves CAN blow a motor up. a combustion engine is designed for the rotating assembly to have constant pressure on the power stroke pushing down on the piston. when this pressure isnt present the piston has no help to push it down. it has to over come its own momentum which cancause major engine damage. thats just my 2 cents.

1vryfststang

+1 had all that explained to me by a ase certified mechanic yesterday regarding valve springs...good information pal

livefast1

yea i just ordered a set of patriot springs that should give me about 100 lbs. at the seat, they were 150 bux shipped to which is the best price i have found so far.

Allen2001GT

sounds good, but the valve springs i'm not worried about. i have my reasons, but ihave to get going. i won't be taking a trailor cuz last time it did break, lol, the last time out, i just came home and got it and went back again. only takes about 25 minutes to get to the track. i'm not worried about this power at all. and just so its clear i will be running the 10lbs spring so it will be making more than 407 just not sure what the numbers will be exactly. i'll know if its too much, but i'm not worried. i'll let you know how i make out. i'll give ya the mod list later too.

livefast1

wait you put the 10 lb. spring in after the tune? and no upgraded valvesprings? i would say forget the trailor and bring a broom instead, that way you can help the tech staff clean the oil and coolant off the track.

oxfordgt

I will agree that valve float will destroy an engine but a turbo does not create enough backpressure to float a valve. The backpressure created by a turbo is just a bit above a stock exhaust system. Valve float is caused by high rpms with high lift cams. When the speed of valve is increased (lift+rpm= increased speed) the valve slams against the seat and bounces because of the weak stock springs. That is why you upgrade springs.

livefast1

that is a problem caused by big cams yes where the cams will actually throw the valves. but a turbo can cause enough restriction to float the valves if the springs are weak enough like the stock 2v springs. i have seen more than a few posts on the turboforums with guys that have had this problem and upgrading the springs have fixed it luckily before the engine blew.