i'm not sure the 440's will supply enough fuel without the rising rate FMU. I still used the FMU with my 440's and 2.87. That increase in fuel pressure under boost really helps push those 440's. Find out if it's ok to tune 600cc injectors on your ssbox and if it is you can use 600's and drop the fmu otherwise stick with the fmu and run 440's.

bigc, i think you're one of very few people that have cooling issues with vortech 2.87 on stock block. It only puts the hp up to about 400 and the tq is sitll pretty low so it's not very dangerous. Most turbo kits on stock block are putting down 400tq and at an earlier rpm so they are stressing the motor way more than a vortech. My cooling temps and quite a few others never became an issue even up to 451hp on a DD dyno.

 

i don't have any cooling issues as a result of the 2.87 pulley so i'm not sure where you're coming from. the only reason i brought up cooling mods is because they seemed to have been neglected in this discussion.

the reason i swapped back to the 3.12 pulley is my tuner was concerned about the additional cylinder pressure on a stock block. regardless of what people on here say, 12-13psi on a stock block just isn't sustainable. to paraphrase his advice to me, the 2.87 on a stock block is a crap shoot. you may be fine, but why risk it when you can run the 3.12 and beat on your car all day? 25 ponies just isn't worth it.

 

oh no, i didn't mean to imply you had cooling issues with your 2.87 but i thought in your thread you did have cooling issues at one point so you upgraded them?

I gained well more than 25hp out of the upgrade. Also it's not boost pressure that causes engine failure, it's torque (or bad tune).

10psi on turbo is way different than 10psi on vortech which is a good example of showing how the pressure isn't hte problem, it's the torque.

 

oh, no worries. my car is just hot...always has been. the cooling mods i did before FI helped a bunch, but there's only so much you can do when you do 90% city driving

with regard to your points, i believed the same thing when i started down this path. i read a bunch on here and got comfortable with what i had to do to run the 2.87 pulley safely (injectors, good tune, supporting mods). your posts as well as str8dum1's were very helpful in explaining all that was involved. when it came time to install i threw the 2.87 pulley on and off i went. the power was good (409hp/340tq) and the car felt crazy fast to me.

i didn't have a full appreciation for all the factors that can cause excessive engine stress and/or failure, however. truthfully, i still don't, but i have a good tuner that has been very good about explaining the risks involved boosting a stock block. everyone always says you'll be fine as long as you keep the torque low, or you'll be fine as long as you have a good tune, etc etc. what few people say is that all it takes is a bad tank of gas and/or high engine temps combined with moderately high boost to cause premature detonation. you'll hear even fewer people strongly recommend guys install aftermarket knock detection. its true that boost on a supercharger is much different that from a turbo. but if your engine starts to ping at 12psi, is it really any safer?

my car is my DD, and i live in a warm area where the best gas i can get is 91 octane. for my own peace of mind, the 3.12 provides the best balance of power and relative safety (if there is such a thing). i'd love to throw the 2.87 pulley back on, but i'm going to do what i can to reduce back pressure first.

 

Ok so it looks like its kind of divided what ppl do here. Ill talk with my tuner

 

ya, thing is, a bad tank of gas with a tuned 375hp is going to do the same as a bad tank of gas on a tuned 400hp.

I've never had a problem with gas because i only use shell but if your daily driver is tuned out to the point where slight decrease in octane will blow your motor then i call that tuning on the ragged edge. My timing was set conservative enough that it was pulled a couple degrees off of what it would do. Plenty of timing pulled to handle bad gas.

Also, with stock blocks there are usually weaknesses in a part somewhere. Granted, 400hp will stress those parts more than 375, but usually if it's going to fail it's going to fail even on no boost but driving it hard.

 

Dude; I'm running a JWT TT with close to 600whp.....on a SS box !!