I am a little frustrated with my setup, and am on the verge of swapping to a HSR and bigger cam, but I want to know what you guys think first.

The best the car has ever ran was a 13.5@ 100mph when my friend stilled owned it. I have played with it a little, but I am guessing the best i would get to to run is may be a 13 flat. It has plenty of tq, but no upper end. I can easily take slightly modded ls1s by 3-4 cars off the line, but watch as the speed past me near the end of the quarter

A quick rundown of what I have:'91 z28 10.5:1 383, Dart Pro 1 200cc aluminum heads,LT4 Hot cam, TPiS big mouth intake, runners and bbk 58mm tb, 32pph injectors, shorty headers, and underdrive crank w/ various deletes. It also has a chip done by Ed Wright.

Now I know it is safe to assume the tune is off. But what are my chances of getting this set up into the low 12 to mid 12's with a tune? I have heard the LT4 hot cam isn't LTR friendly, but is there any trueth to that? I would like to work with what I have, but if I need to change cams then so be it. I would like to keep the intake set-up, but is it that restricting in the upper rpms?

I have read past posts on low hp high tq dyno's, but the shootout sticky's dyno numbers for the intake I have keep my hopes up.
On a side note, I do have the 5151 NOS kit(not hooked up) if that makes a difference on cam selection if I need to change it.

Any opinions would be very appreciated,

Thank you
Roy

 

Hotcam works fine on LTR setups, my 350 had that and I wish I stuck with it in the 383 I have now :-)

What kind of 60ft times are u talking?

Also, The "chip" Ed Wright sent u will not be right and you will need to go thru a lot of logging and sending it back and forth to get it right.

I had this happen to me and I was so po'ed by it all I started doing my own tuning.

I honestly believe u have a lot to gain there.

Would be the first way I would go, after verifying everything else electrical and mechanical.

Heads are a little on the large side for what u are trying to do, but should be okay being you are running a 383

later
Jeremy

 

Try finding a dyno day, can usually get 3 pulls for like $50, that will let you know if you have a chip tuning issues.

What is the rest of your exh system like other than the shorty headers?

 

Well, I am sure the chip needs work. I am pretty sure there is too much total timing in it. If I advance the base timing, it definetely has more tq, but kills the upper end ( I assume due to pinging) and vise versa when I retard it. Unfortuantly, the cable I used on my tbi's for winaldl appearently doesn't work with the tuned port ecm.

The exhaust consists of edelbrock tes headers and y-pipe and two cats, to an slp catback. I do have a cutout on there after the cats, which does make for a sotp difference when open....but that isn't often.

I will probably go with long tubes down the road, as the tes headers just make things that much more annoying to work around. And there are definite gains to be had w/ LTs.

I will definetely get into tuning it, but would it be worth it to try to go with something a little bigger? The heads should flow well, and unfortuantly I have the 58mm TB....which could be a good thing though-if the LTR setup can support a higher rpm cam. I can actually get a cc306 for $100, but I also love the specs of the gm 847...so much I have one for my other 383 project. Could my tpi set-up support either of those two cams?

 

You need to scan it when running wot to see what is happening. I bet it's lean and you are getting knock retard. Ed runs his chips lean, mine was 13.4 to 1. I started tuning my own shortly after wasting money on him.

Get a scanner or logging program and log some data.

 

what I am about to say is soley me opinion so dont anybody go and jump down my thoat for anything.

I was in the same boat as you where and I finally realized that the chip thing wasnt going to cut it anymore with my setup and my future plans so I broke down and bought a FAST setup. Yes, I know it is a little pricey but from the looks of it, you like to go fast. Ditch that stupid slow *** ECM and step up to the big leagues. I paid $1400 for a brand new setup complete with harness, ECU, and WB O2. My $350 "custom" chip from Ed Wright now sits in one of my draws of my toolbox. the FAST setup woke my car right up. it was night and day difference from the chip. I feel that the FAST ECU was one of the best investments I made to my car. you can also wire your nitrous setup directly into it. Look around for the older FAST setups, the prices are coming down on them due to the new XFI version that just came out
Oh and ditch the TPI style intake setup. I know you said you want to go to a HSR and that should let your 383 breathe a lot better. You may loose a little Tq on the low end but Im sure you can find it somewhere else in the engine. I put down 300 RWHP on a mustang dyno with my setup and I am running AFR 190 heads with a VERY ENGINE SAFE tune in it. Id say I could easily put down about 330-340 hp on a typical chassis dyno. I am also running a "street friendly" cam as well. With the chip I had I only put down 199 rwhp so I picked up 100 HP to the rear wheels by ditching the stock ECM. take that for what you want

 

I have thought about an aftermarket engine management system. I am actually going to be running the commander 950 w/ wideband w/ a 4bbl tbi on my 383 in the rs. I know it's the "lower" end of management systems, but there are many benefits of the system that fit myself and that project well.

I will agree that the ed wright chip is junk, and thankfully the previous owner paid for it an not me..... However, there is plenty to be had w/ the stock ecu. My old 383 in the old rs ate supercharged cobra's from start to finish w/o a problem and that was with 160baud and a holley 670 tbi, multiple chips done by tbichips.com. I am much more confident in the '730's higher baud rate as well and look foward to tuning w/ the autoprom.
However, the rs had an edelbrock rpm airgap, and inch adapter plate and modded holley tbi. It had plenty of plenum and access to air, but ran lean in the end (thus the reason for going 4bbl/4 injector this time).

In regards to the Z, the more I look at it, the more miss match I think my combo is. If I can hit 12.5s after tuning, then I will be happy. If not, the cam will be the first thing to go and most likely be replaced by the gm 847. If that doesn't work, then the HSR will be going on there.

Thank you for the input.

 

Also, if anybody else has opinions on my set-up, please give me ideas.

The more I look at it, the more miss matched it seems. The heads should flow well. However the cam is small (218*/228* and .525/.525"), yet I have a high flowing tuned port set up and a 58mm tb. I don't have the stock tb, and would rather invest in a cam as opposed to smaller tb. But at the same time, I am still learning tpi. I am not sure what kind of rpm range the tpis setup is rated at. But I would definetely like to hit the 460hp that it made accourding to the sticky in this forum.