formula305

iTrader: (7)

Hey guys,

I don't post here much but I read all the time. I have a 2000 TA with a 383 in it and Im really not sure if my power and track times are where they should be with it. Im looking for some opinions about if it looks good where it is and if not what you think I should do to make some more power.

Here is the setup
-383 in an LS1 block, -6cc Mahle Pistons, Scat Rods, Eagle Crank. Compression is about 10.9:1
-PRC Stage 2 5.3 heads that I bought new 2 years ago for the 346. 2.05/1.575 valves, PRC platinum springs which are good to .660 lift.
-Cam Motion custom cam that was originally going into a MTI 427. Duration 246/253 Lift 632/643 on a 112 Lobe Sep.
-Fast 90/90, 85mm maf and air lid
-36lbhr Ford Red top injectors
-Racetronix Kit with 255l Walbro
-Pacesetter 1 3/4 longtubes, no cats, 3" I-pipe w/18 inch bullet & a magnaflow.
-M6 with a Spec Stage 3
-Moser 9" with 4.11's and a Truetrac

I dyno tuned the car many times, pretty much after every mod. Spent about 3 hours on the latest tune. Air/fuel was pretty solid at 12.7-12.8 through the pulls. The best all motor track pass was an 11.47@119 on a 1.76 60'. Best Nitrous pass was 10.86@131.9 on a 1.65 60' with 200 spraying. Here is a dyno sheet of the the best motor pull (red) and with a 100 shot (blue). Any insight you guys have will be appriciated. Thanks, Joss.

lilbuddy1587

iTrader: (1)

Alright man here's how I see it; your cam is a little big and I'd say thats taking a tole on your DCR based off the information you gave, I don't think a 90/90 will support a cam that large, the overlap of the cam is not agreeing with the restrictive exhaust, and the rear end and gears is robbing a little power.

Trap speeds aren't looking too good.

silverbeast

iTrader: (16)

It sounds like your combo isnt matched up to well. Are you sure on the compression? As for your times at the track ...they are a little slow. We have a cam only car here that ran an 11.16 @ 120 w/ a 3420 lb race weight. anyway good luck with your car and hope you get it figured out.

ArrestMeRed99Z28

iTrader: (1)

I think if you put in a little 230 something cam you will be very pleased by the results, or give TSP a call and have them recommend a cam for you based on your Intake, Heads, Cubes and Exhaust.
AJ

WS6FirebirdTA00

iTrader: (33)

I wouldnt call them to match up a cam, and I wouldnt do anything unless you know for sure yours is setup right. How was the cam installed? Strait up? To me it looks like it could be a possible install issue. I would have been nice if they gave you a better graph to look at, the scale on that one sucks. There also could be some other issues, but this is a good start to check out. The CR also seems pretty low for that setup.

burritoboy9984

iTrader: (1)

I would think the compression would be a little lower with dish pistons and 5.3 heads...

-Erik

brad8266

iTrader: (23)

There is something wrong with that. I would do a leakdown test first too see if there is anything wrong in the motor. That cam is not a bad choice for a 383. Your numbers should be way higher than that. I suspect somethings not right mechanically.

formula305

iTrader: (7)

Thanks for the input so far guys. The cam was installed straight up it does have a +4 ground in to it though. I was kinda leaning towards the cam being to big too, especially on the lift. Those heads are probably falling way off after 600 lift. I have a TSP 233/239 .600/605 that was in the 346. It made 418hp/385Ft-lbs. You think I should throw that cam back in?

lilbuddy1587

iTrader: (1)

I would. That'll bump the DCR up and things should improve. Also, I dont think you have the exhaust setup to support a cam with 25+ degree's of overlap either.

brad8266

iTrader: (23)

Higher DCR isnt really going to do anything for those peak numbers.

ArrestMeRed99Z28

iTrader: (1)

I partially agree with Brad, you should do a compression and leakdown test and if everything come up alright, stick in the 233/239 I think that'll be a super streetable really torquey good bye tires set up.
AJ

WS6FirebirdTA00

iTrader: (33)

More compression will help, but he isnt going to gain 50 hp and 100 ft lbs, thats for sure.

I would do as recommended and check out the cranking compression and do a leak down. Make sure there isnt something else holding you back. I would have a hard time believing that cam is going to cut your power back.

JayplaySS

iTrader: (15)

Cam does appear to be too big. I had the same TSP cam 233/239 and I would swap that one back and retune and dyno. Your heads are only good for 300-320 cfm so that cam needs too much air. My .02

santiago

iTrader: (28)

i say keep the cam and strap some e.t 240's on, along with some 1 7/8 headers and also get an sd tune.

ONEBADWS6

iTrader: (22)

Do a leak down and a compression test. You may have some loose valve guides who knows. The cam is not to big, I run a 258/262 on a 110 hyd and seem to make plenty of power. Also my headers are 1 3/4 to 1 7/8 so I don't see that as a problem either. I would say there is a problem with the heads or the rings in my guess.

lilbuddy1587

iTrader: (1)

I think it would help peak a little but even his power under the curve is sloppy and thats what I was getting at. As far as his exhaust goes and the by product of overlap from that huge cam arent mixing well. I honestly think some stepped 1 3/4 to 1 7/8's would work well and I dont think the bullet in the I pipe AND going through the maggy muffler is helping things.

formula305

iTrader: (7)

Ok, well here is what I am thinkin. Next weekend I will plan on a cam swap. At the sametime I will do a leakdown test. I really dont expect to find a mechanical problem though. The engine was built buy a very reputable local builder. Ill try the cam swap first and if going smaller helps I can go back to the bigger one once I get some better flowing heads. Besides the 233/239 I also have a 244/244 .612/.612 on a 112. Which one do you think I should try first?

Asmodeus

the 244

AINT SKEERED

iTrader: (2)

I would do the 244 as well. and put a cutout in the exhaust to see if that is where your power is at.

ONEBADWS6

iTrader: (22)

Gee I forgot I don't know anything and have a 12 sec bolt on car. Have fun changin cams and getting no where.