dbusch22

So, I've been a member of z28.com for over 10 years now, bought my 1st Lt1 car in 2001, been an adict ever since.. I'd probably be into LS1 cars more if they hadn't been so pricey back when I got my start. Now, I've got too much time, money, and more importantly emotion, invested into my 1994 TransAm.

It actually started as a 1995 TransAm, that was in nice condition. Well I was young and dumb, and beat the living **** out of it for a few months until the head gaskets blew. After that, the rear end went, so in went a set of 4.10s. Finally about a year later, spun a rod bearing. Crushed, I looked to a good friend who had just finished mechanic school. Together we built my 1st 383 stroker motor. (12:1 CR, cast internals, so it's clearly not bulletproof and certainly not able to handle boost or Nitrous.) After another couple years of fun with the car, I was hit by a woman who ran a red light.

Well that was the end for that car and the beginning of Frankenbird. I bought a 1994 formula, and swapped pretty much everthing over, ground effects, hatch, rear bumper, side skirts, along with that came some upgrades, a 2002 ws6 front end, a set of Torque thrust II wheels, a new heads and cam for the 383, a moser 12 bolt, complete repaint, upgraded sound system, dynamat, suspension upgrades (tubular parts) and some other things.

After a rapid 6 months of building, the car was completed and ready for the road in the summer of 2005. The car has been a blast to drive for the last 10 years. A wife, a degree, a 5 year old boy, have left the car on the back burner for the last few years, however I still try to make time to get 1000 miles on it each summer. (wisconsin)

My son is starting to get interested in cars, and has asked me on many occasions to build a car that does a wheelie.... (we won't go there, lol) so now it's becoming a little bit of a conversation piece between us, and I've been itching for a power adder as I've grown quite accustomed to the 400+ Hp that the car currently makes. The car makes about 1 track appearance a year and runs a respectable 12.0x at 115mph and trapping 1.6's - 1.7's 60ft time with M/T ET streets. I should mention that this is an T-56 car.

I enjoy parting these cars out for fun, and extra cash, so every time I run across a car that has some better parts than mine, I keep them. - Frankenbird is pieced together from probably over a half a dozen different cars.

This brings me to the current project. I came across a 1995 z28 with a D1sc twin intercooled procharger. The "kid" I bought it from wasn't the builder, and he wasn't very versed with the LT1 platform. Most of what he told me was speculation as he couldn't verify any of the specifics regarding the build. Basically what I got from him is that he bought it as is, beat the crap out of it until the motor went "knock knock knock"

He claimed (and I won't be able to verify any of this until I get into it and start tearing things apart) that it's a forged rotating assembly, and a complete LT4 top end, don't know if it's been ported or anything. At any rate, I bought the car for $2800, so it's worth it for the procharger alone.

My plan is to transplant the entire engine (after proper rebuilding), and blower setup into Frankenbird and make it a 10 second car.

I have a lot of concerns and a lot of things to learn. I've read the stickys, I've been reading things online with some degree of speculation, almost every day. I have two books on order from amazon "How to build max power chevy Lt1/Lt4" and "1993 - 2002 camaro firebird performance handbook"

I would like to cover topics here regarding all aspects of this build, Motor, ignition, exhaust, fuel delivery, and anything else that may be pertinent to the build. This project is slated to begin probaly in Early march and will start with removing the powerplant from the z28, and then diagnose the motor problem with that car, and prepare for a rebuild. I will have the motor rebuilt by a reputable shop so nothing there to concern this discussion aside from what combinations to use. heads, cam, valves, etc.

Now, I have nicely ported heads in my car, and I have no idea what is in the car that I'm about to get into. If the car has stock unported LT4 heads and intake, I'm leaning toward keeping mine, but then again, I've been reading that the head deck on the LT1 castings can't handle much more than 8lbs of boost or the head gaskets may become unstable. (head gaskets are another topic I need input on) So it's preferrable to use seme aftermarket heads that have a thicker deck. I would prefer not to spend a ton of money buying new heads, so if they'll hold up just fine, I will use them.

With regards to the ROTATING ASSEMBLY in the donor motor, for cost savings, I'll reuse what I can. I'm not sure what's going on, but the motor will only turn 1/3 of a turn in either direction. Maybe a rod let go. We'll see - I see no need to waste conversation speculating on what's going on in that motor as far as damage is concerned. I'm HOPING, that maybe I replace the rods, have the crank polished (if there are any bearing failures as well) and throw it back together. I'm also hoping for some nicely dished -31cc pistons or something.

Fuel systems... My current setup is a simple walbro 255, stock lines and regulator, feeding a set of SVO 36lb injectors. I realize that some serious upgrades will need to take place in order to feed a potential 700 bhp. please comment on the following:
- fuel pump wiring upgrades... options? (voltage drop, hot wires, heavy amp load, etc)
- new style 340lph good choice?
-twin in-tank setup (which the donor car CLAIMS to have)
- stay with the walbro 255lph and add an in-line booster (racetronix style or equivalent)

with regard to FUEL LINES. For cost savings, I would like to maintain the stock lines from the tank forward if possible, but have read that they will handle about 500-600 wheel HP which is right around the range I'm hoping for. SO, will the stock lines make the cut? or am I going to have to go with an 8an feed line and a 6an return line (which I have read is what would be needed to handle up to 1000hp) stock lines are about a 6an, so the next steup up would be the 8an. I've seen a lot of crazy setups, where people are welding fittings to the back of the fule rails for larger lines, and running two independant feed lines, one to the back of each rail, then, return lines in front, etc... please comment, is all this necessary to fee 700bhp?

INJECTORS - I've done the equations, please chime in, give me opinions and lessons learned. expected HP ~700 x .60 (boosted application) / 8 (cylinders) x 80% duty cycle = injector size. So following that equation 420 / 6.25 = 65.625 lb injectors. Is that a good choice? and then there's low imp vs. high imp.

Camshaft..... Ya I got nothing there, maybe see what is currently in the car, have it inspected, cleaned and reuse it if it seems appropriate.

Valve hardware - re-use it if it's decent shape, quality and performance minded. ?? Comments on springs, valves etc would be appreciated.

REAR END GEARS. On my current setup, running the 4.10s is great for the 383 because I finish the 1/4 at just about the peak end of 4th gear, at 115mph. I see most of the decent 383 F/I cars finishing in the mid-130mph range, so that would take me to 5th gear, which is not a happy place to be. I'm thinking about stepping back to 3.73s or maybe a 3.55 or 3.42. Thoughts?

I want to make this a safe, reliable motor, that will last a long time, and not blow up on me every time I step on the throttle. I want to be able to get on it withough constant fear of detonation. I don't want to build a motor that is on the brink of destruction. Thoughts on boost levels 8, 10, 12, 15lbs? I'll tell you that two pulleys came with the car, I have no idea how much boost the car was making prior, the pulley that is ON the car is the larger of the two, the extra one I have is about 3.8" dia. I'd like to use one or the other, pulleys are very expensive, and I don't want to buy a bunch and experiment. It's also note worthy to mention that it's an 8rib pulley setup, and I do not plan to upgrade to a cog style, or 12 rib. There has been a lot of topics regarding belt slippage, and belt degredation with the 8 rib setup.

I also would like some clarification on "crank Snout" issues. I've read about people snapping off the front of their crank or something? Is there some sort of ATI upgrade or something or a adapter, and something to do with a keyed crank hub... all confusing at this point. Please make comments on the stock dampener, is it necessary for me to ditch that in favor of a fluidamper or equivalent. If it's necessary it's necessary, but I could see better places to stick $400 in this build if I can get away without it.

Water / Meth injection... necessary?

Timing retard controller, etc..... something i've never dealt with, needed or not?

IGNITION - Current setup is a stock OPTI (believe it or not) and an MSD blaster coil, with a larger than stock, Over the vale cover wire set. Knock on wood, it's been great, and I've never had an issue or needed anything more. SO - will I need to upgrade ? I've researched so far, that it'll work, but that the 24x conversion is better, a delteq would be better, or one can simply piece together many of the needed parts, coils, etc, from junkyard vehicles and cobble a system that is similar to a coil/cylinder setup (ie. LS1) please comment. I've heard not to run an MSD 6al type box with a blaster coil, or similar... that you can actually burn up your opti faster. Afraid to have to deal with those nightmares, I've left mine well enough alone and just upgraded the coil and wires.

COOLING SYSTEM - short and sweet, the donor car has a BeCool radiator already installed, I may keep it, may sell it, who knows. From what I've researched the stock cooling system is more than enough to handle over 800HP I'll keep my Meziere water pump and 160 powerstat and that should suffice, but if i've misses something I'd like to hear it.

I've mentioned several times throughout this post, "to save money" Building a F/I car inherently is not "to save money" - it's expensive and I understand that. In my case, I have two key elements controlling my project funds. The first, is that I've got a donor car, that I could just CHOOSE to use everything that it had already, but in my mind, if the powerplant failed, it was likely from an inadequacy somewhere in the build... not enough spark, not enough fuel, poor tune, something... caused it, so I want to build it better than it was before.
The other key force is my wife.... I pitched her this whole thing a couple months ago like this: ok, so I have this donor car, and I have (from all my other parts cars) enough parts that I can get the car running with a stock motor etc, after I have kept the things I want off it, and probably sell it for $3000 - essentially breaking even on the motor and blower. Then, I'll be selling the 383 out of my car this spring, and should make a bit of decent money there. Hopefully this build will not cost me TOO much out of pocket, it certainly will cost THOUSANDS less than if I were to rebuild my motor with forged internals, and buy a new supercharger kit from ATI with all the supporting mods.

I'm sure I may have overlooked some important aspects of this build, some parts that are extremely important, I would like to learn from others mistakes, and others' victories. I appreciate your comments and look forward to reading what you have to say. Let's make this a great discussion about our cars and try to stay on topic and not beat people up about their opinions, let this be an open discussion!

97WS6SCharged

Honestly if I were going to build another FI LT1 I would stick with a 355 over a 383 or 396. Much better selection in pistons that don't have thin crowns or ring packs. Don't get me wrong, good piston manufacturers like JE or such work well but even 700 hp gets old faster than you would think when it's always there (not like nitrous where you have to refill the bottle, turn it on, heat it up, etc...). Anyhoo...

Cylinder heads... There's nothing wrong with the LT1/4 deck thickness. Plenty of clamping force from the 5 studs per cylinder to keep them in place and keep even normal 1074 felpros alive. The downfall for FI is the small chamber volume which necessitates the rather large piston dishes with a 383. If you were to upgrade to say a set of Trick flow heads with the 64 cc chambers that would allow you to run a better piston on the 383 and still keep the compression around 9.2-9.5 ish.

Fuel System... I was fine around the 700 flywheel mark with stock lines and a single 340 pump but started having issues with the cross over around the 700 rwhp mark. I upgraded to -8 feed and -6 return lines with dual 340s (twin 255s also work, I just got a good deal). Both ran all the time but I have a A1000 regulator to control pressure. As far as wiring goes I ran 2 10Ga wires from the battery to relays mounted in the back (1 for each pump). The grounds were also -10 but chassis grounded to bare metal and painted over. I'm seriously considering ordering one of Nasty's fuel tanks with 3x 340s in it because I don't really want to try to fit another one on the stock hanger (there's literally not enough room on the hat for another pipe).

Injectors... I'd run (and I do run) a set of Mototron 80 lb injectors on my 408 motor. They idle fine and have enough capacity to do more than you're planning for at the moment. Dave may have me convinced at some point to upgrade to the 127 lb'ers but not yet.

Cam... I would invest in a custom grind if you're spending the kind of money it takes to make an FI car run. Have it ground to match the heads, gears, driving habbits, etc... Talk to Martin @ Tick Performance.

FWIW, the cam in my 383 (done by the head guy at Erson) specced out to 234/250 @ .050, .580/.580 lift on a 114+4 split. It was a compromise cam that was designed to be drivable without killing the springs before 50k miles.

Valves... the LT4 intake valves actually work really well. I'd invest in a better set of exhaust valves though.

Gears... If you've driven a 400 hp car with 4.10 gears then you know how useless 1-2 and part of 3 are. Double the HP and even 4th gear is scary. FWIW with 3.50 gears in my 9" I could turn street tires over in 3rd gear at will at 70 mph. I really liked the 350 gears with the T and YSi blowers and the 6 speed as long as I had good tires on the car. Gives you enough low end to move the car but 4th is good until basically the top of the stock speedometer (155ish @ 6800). Ran through the standing mile at 192 @ around 6300 rpm in 5th.

Pulleys... You need to figure out the impeller speed where you want to shift at. I was running 2.75 and either 7 or 8" crank pulleys on mine and was actually overspinning the blowers by a few thousand rpm (not a big deal). I will say that a D1 should have no problem pushing 15-18 psi on a built LT1 if you just want a number on a boost gauge. Run the pulleys that get you the boost required to either make a dyno number or (better) run the pass you want. Also, I would go with a 12 rib before I ran a cog on the street but that's just me.

Crank Hub... You need a crank that's machined for the BBC snout or it won't work. Good upgrade if you're going to order a new crank though especially on a blown car. With a D1 I would just run it with a good belt setup as long as it's a good 4340 crank.

Meth is nice to have when the summer rolls around. You might look into ditching the twin intercoolers for a nice front mount. Much more efficient.

Ignition/PCM... Spend the cash and upgrade to the 24x system. HP tuners and a 2 bar map are worlds ahead of Tunercat.

You may not need a bigger radiator in Wisconsin, dunno how warm it gets in the summer or how much stop & go traffic you see. I stood my radiator up in the car using a dual pass setup since I had planned to mount my turbos up front originally. Plans changed. Anyway, a beefy cooling system is never a bad idea when you're talking greater than 500 rwhp.

The SRZ

You decide to go 12 rib, I've got a perfectly running SDCE setup I'm selling. Brand new belt, 7.65 crank, 3.85 and 3.7 blower pulley...switch to HOB Cog.

dbusch22

Not that I have any idea of im going to need or want the sdce setup, but how much would you be wanting for it. Feel free to PM me. Thx

The SRZ

Sent you a PM

Josh Harris

the guys at lt1turbo.com are running forged eagle motors I ran a 396 forged golem an ran a 9.7 15psi t78

sscott

Thanks for the fast responses, I will be returning to 43.5 psi this weekend.