93 camaro z28

[tsirocks]

hello i am new to this board. ok i have a 93 z28 i am going to do heads and a cam. i am looking at doing the lt4 heads, hot cam and intake manifold. i have seen this advertized at over 400 hp. has any of you done this?? what did you get? also is there any speed density owners that have custom chips? or should i go right to a accell dfi or something?
i am also considering just saying screw it and putting an intercooled procharger on it. any advice would be helpful.

[N20LT4Bird]

We've had this debate before. I think its worth it. W/O the N2O I am running close to 109 mph in the quarter. I dont think the tune is on the money either. I have more than just the basic head and cam package though. Plan on spending a bit more for the package than just the 2000 or so. Computer mods, porting, etc etc..

[Injuneer]

The 93 fuel rails are different from the 94 and later rails. They are designed to support the "batch fire" injection control used in the 93's (compared to the "sequential" used 94 and later). As a result, they will not fit on the LT4 intake manifold. You would have to switch to the 94 and later fuel rail design. Might be a problem with the batch fire fuel flow.

As far as the "LT4 conversion kit", you might want to try a "search". This subject gets covered every few weeks or so, and there is a lot of info already available.

[N20LT4Bird]

Does it matter (as far as the fuel rail is concerned) whether your firing the injectors sequentially or together? I wouldnt see that it makes a difference as long as your running the same pressures and flowing the same amount through the injectors.

I would think he could keep the same fuel managment and just change the rail.

[Injuneer]

I'd be concerned about the hydraulic shock in the "batch fire" system. Your firing all 4 injectors in one bank, and then all 4 injectors on the other bank. But the banks are piped in "series" in the 94 and up rails. That is going to raise hell with the fuel pressure in the rails bouncing all over the place. It appears the rail design - the supply/return line configuration, not the rails themselves - was set up different in the 93's to account for this. I know from using 75# injectors (sequential) in the stock rails that there is a benefit in putting the rails in parallel, not in series. That's why I supply both rails from the back, and take a single return of the cross-over pipe in the front.

Can't say with absolute certainty that the switch would be a problem in a 93 making 400HP or so, but I wanted to make him aware of the differences and the potential problem.

[N20LT4Bird]

I dont know, I think there could be a "hydraulic shock" by unloading a batch at a time. I think it would be a matter of at what HP or fuel consumption level it would be at. Obviously there is at the 275 HP level with the 93 rail. I would be better equipped to argue one way or another if I could look at the rail and compare it to the 94 +up rail.

It would be interesting to find out though. tsirocks, do you want to be the guinea pig?

good discussion though

[KnightFire]

I'll throw my .02 in
Actually I was a guinea pig about 4 years ago when I converted to a 95 Intake with LT4 fuel rails when I did my first LT4 build up.
I had no problems what so ever with the setup. However, I will add that if you intend on going on to bigger and better which I have, you may run into problems. I am now experiancing a load problem at idle which might be attributated to the fuel rails, because my A/F ratio is pretty much on the money. I won't know for sure until I get my 300+ back online to help those NGK6 plugs fire better below 3000rpms and get the DFI tuning down.

As far as getting a chip contact Alvin at www.pcmforless.com he is probably the best there is out there IMHO. He is still helping me with a chip to control the TC lock up points. Tell him I sent you, he'll treat you right!


KnightFire

[N20LT4Bird]

I think if the rails were your problem, and you were experiencing a hydraulic shock (I like that term - thanks Injuneer) your air/fuel ratio would be lean, due to the lack of pressure between batch pulses, especially in those cylinders closest to the front of the engine (farthest from the fuel lines). - my $.02

[tsirocks]

fuel rails

aeromotive make lt1 fuel rails dont they? what about other aftermarket ones? im sure i can make something work. is the lt4 manifold worth the trouble anyway?

[Injuneer]

Re: fuel rails

Originally posted by tsirocks
aeromotive make lt1 fuel rails dont they? what about other aftermarket ones? im sure i can make something work. is the lt4 manifold worth the trouble anyway?

Not that I am aware of.... neither Aeromotive or any other aftermarket source makes "LT1" specific fuel rails. They don't need to. The stock rails, will support 750HP easilly. Above that, simple mods will make them suitable for up to 1,500HP. But that's the stock 94+ rails. I just don't know enough about the 93 rails, except that they will not fit on the LT4 intake manifold, and they are piped differently than the 94+ rails.

Yes, the LT4 intake is worth it, because you can't use the LT1 intake with the LT4 heads.

Point is, the "LT4 Conversion Kit" incurrs extra costs for a 93 owner because of the rail issue. That makes having your stock LT1 heads ported and getting a cam at least as strong as, if not stronger than the LT4 HOT cam, and a set of 1.6RR's becomes very attractive.

[tsirocks]

heads

i was looking at thunder racing heads, i might go that route.