Well this project is finished and I would like to say that I am pleased with the results but its about 50%. Car runs and drives awesome and plenty of power for a convertible and can easily shred the 315/35ZR17 tires on the back of it. Car pulled 348hp and 352torque at the rear wheels on a mustang dyno.
1. Everything works, cruise control, AC, TACH, speedo, everything is like it should be in the car so I would give that goal a good check.
2 well the horsepower and torque which is a little less than what i was hoping for but car is definitely not slow.
3.I will run it at the local 1/8th mile track sometime and see how it does before driving too far to end up running high 12's to low 13's with this thing.
4. Streetable it is. This version with the LT4 Hot cam has a nice lope and is extremely nice and smooth on the street although below 30mph you do still have to be careful as it will spin those 315/35s HARD at below 30mph.
1. LOTS of research. I have asked everyone who has built such an animal on every Camaro forum that deals with LT1's.
2. I bought a set of the stock Aluminum heads on ebay for $150. Decided to run a Advanced induction 180cc street/strip CNC port and polish for those heads and cam combination with their valve train upgrade which includes 7/16 screw in studs and guide plates and comp cams chromoly 1.6 rockers. I got the cam with the package that I bought from advanced induction comp cams custom grind 234/242 duration @ .050 on a 110LSA. must say the engine has one nasty lope to it with that cam. I chose Advanced induction for a few reasons. 1. they turned out to be located only 50 miles from me. 2. They get some pretty good flow numbers (really close to a more expensive LT1 AFR 180 head) while still maintaining a small 180cc intake runner which will keep the velocity high during the engines part throttle driving which will help with the driveability of this setup. 3. After visting Advanced Inductions shop and talking with Phil for an hour, I feel that my money would be well spent with them.
Flow numbers looked good but don't know if they are the reason for the lower than expected dyno number or what. that comp cams is the one that messed up and I didn't like the streetability for cruising as it had too much CHUGGLE (kind of a jerky lugging feel at less than 2500 rpms) with my 2000 rpm stall and 3.42 gears so while engine was out I replaced the cam with a LT4 hot cam which sure didn't sound as cool but had a decent lope and far better drivability. .
3. I am not doing much to the stock intake. I will have the holes in the intake enlarged to match the new throttle body and that's about it. A good acid dip to clean the corrosion out of it but no other real work. I sent the stock throttle body to www.rvmorsemachine.com to get bored to 54mm from the stock 48mm bores to feed this machine. I didn't really need a 58mm and bored stocker pricing for the 54mm bore is reasonable and they have done TBI's and Vortec throttle bodies in the past and I haven't had any issues with them.
4. Well the first dyno on the first engine was done with 44lb accels which gave me nothing but troubles and send out for flow testing and the results were just as bad and so no more Accel injectors for me. they were that bad and to top that off a week after they came back one stuck wide open and hydrolocked the motor and fortunately it was during startup so it was just cranking pressure and didn't seem to hurt it. I changed to a set of flow matched 42lb injectors from www.racetronix.com and those are working out well with nice even coloring on the spark plugs but with those power numbers if they are accurate the stock 24lb injectors would have been fine.
5. Since this motor looks so bad, I decided to chunk the rotating assembly and put a 383 stroker kit in it. I went to Frank at http://www.gofaststuff.com and purchased their $600 kit with speedpro hyper pistons. I did have them change to a H860CP .040 piston which will give me about 11.7:1 compression once I deck this block a little. That change did not increase the price of the kit and Phil at advanced induction reassures me that 11.7:1 is not too much compression on a reverse cooled LT1 motor. I wouldn't go quite that high on a std motor but Phil helped explain to me why I could run that extra little bit. I could have gone forged but the price is a LOT more and this motor is going to put an awful strain on that convertible's chassis even with its subframe connectors so no power adders will be used on this motor. I do however plan to have the rotating assembly balanced with the factory flexplate attached since there is a shop here locally that can do that.
I did have to replace one piston when I had to go back in the motor after the first dyno pull with the comp cam and since I went with a milder cam I went with a thicker cometic multi layer steel head gasket to get the compression down to 11.4 which seems to be doing fine so far with no detonation issues with 93 octane fuel only.
6. For exhaust, I changed everything. I did end up using Hedman 68479 shorty headers with a D shaped inlet to match up with the LT1 heads. I would like to have run long tube but I didn't want the exhaust to drag on everything. I ran from those 2 2.5" pipes over to the passenger side and under the passenger seat connected to 2 2.5" magnaflow cats. from there I still went 2 2.5" pipes where I matched up with a flowmaster 2 into 1 collector FLO-Y300400 dual 3" inlet to 1 4" outlet. To that outlet I connected a Mufflex 4" mandrel bent cat back setup with a spintech 4" muffler exiting through a single 4" hidden turned down pipe. Motor has a wicked sound to it and I will be recording it for you the next trip to the dyno. Setup did turn out to be somewhat louder than I wanted but it does sound mean. I have had great success with the flowmaster collectors to Y 2 pipes together on other projects and so I knew that was a must. I may have sacrificed a little horsepower with the headers but it doesn't hang lower than my subframe connectors do Well that 4" pipe back there does a little in some places.
7. Wiring. I ended up using an aftermarket harness from superior harness company and it went right on but did cause me a couple issues with the programming that took a little while to figure out with the transmission but I think a new harness will cause less headache in the future with new wiring and connectors. Tapping into the wiring for the gauges and such in the car wasn't too much issue although I don't have the cruise connected yet. Main issue is with the tach which is now reading twice the RPMs that the engine is actually running and when I figure out a solution for that, I will let you know.
For the tach, I used a dakota digital tach calibration box from www.eficonnection.com to straighten out my tach. I had a similar issue with the vortec 6.0L swap in the 94 dark knight project truck as well.
8. I am going to use a 1994 4L60E with this setup so I can setup my shift points exactly the way I want. I hate messing with governor springs and weights on the 700R4/4L60 that is in the Camaro now. A friend of mine that owns Friendly Transmission service in High Point NC is building the trans for this project. Using everything high performance we can find to go in this thing. I decided to go with the S10 2000 rpm stall converter like car had since I am not looking for a primarily race car but rather a good street car so I didn't want to screw the gas mileage up even more with a high stall. 385ci should make plenty of low end torque to not need too much stall..
Well at this point Project Serious Black is officially DONE. Here are the dyno numbers which aren't bad for a mild very streetable 383 LT1 automatic. Most say that a mustang dyno typically reads lower by almost 10% than a dynojet that I used to use. I can say that the car is faster than I need in a convertible. If it were a car that was ever going to see track use, I would have used a bigger cam but in a nice street car that car is fast. 348hp and 352lbs of torque considering 20% drivetrain loss = 435hp and 440lbs of torque and you can see the horsepower was at a nice low 5900 rpms so I don't have to rev the snot out of it to make good power.
For you guys that might like to see the rear of the car with those 17X11 ZR1 wheels with 315/35ZR17's tucked under a thirdgen car.
That is with a 1.5" spacer on the 17 X 11" rear wheels and 315/35ZR17tires and 2" spacers on the front and the spacing put the wheels and tires nice and even with the 275/45ZR17 fronts on the 9.5" 17" wheels on the front.