hog

You can tell the PCM to do whatever you want, it just wont do it.


1. I have a Fastchip tune which they set at 6200 rpm, I only get a 5800 rpm limit. Just because they can SET a rev limit to whatever they want, doesnt mean the PCM is going to realioze this input. ASK YOUR ED WRIGHT FRIENDS ABOUT REVVING AN LT1 PCM OVER 7200-7400 rpm, it cant be done with the stock LT1 PCM, no matter what number you enter.
Fastchip has been using the intake as an excuse for them not raising rev limits higher for many many years now. Fastchips is an excellent tuning company, my truck dropped 3/4's of a second with a tune by Ed Wright (Fastchips) and Hooker longtubes.
A friend has a 230/245 cam and asked Fastchips for a 6700 rpm limit. The PCM they send was indeed tuned for a 6700 rpm rev limit, but 5800 rpm was the resultant.
2. I have Tunercats which I can set to 9000 rpm and still get a 5800 rpm limit.
With Tunercats i can lower the rev limit down from the stock 5600 rpm and raise it by 200 rpm up to 5800 rpm, but no higher than 5800 rpm.

I would love to read a copy of the flash that you have. I am willing to bet that it wont rev over 5800 verified rpm.

Someone talked about an L35 cal file in an L31, I have tried that also from TJ.

The MArine intake is substantially better than the stock L31 intake. even with my stock cam I can pull it up to 5800 rpm with substantially less power droppoff than the stock intake allowed. I wa sthe 2nd person in North America to install and run a marine inatke on an L31 truck. I did it because so mnay people said it woudl nt work
the intake manifold has absolutley nothing to do with this 5800 rpm rev limit ceiling.

i would love to see a back to back dyno test between a marine intake and a Ramjet intake. The MArine intake uses a cross ram design with 8" intake runners. The intake air is forced to make a serious 90° turn where the Marine intake does not.
With the marine intakes has much more plenum volume than a stock L31 truck intake.
The Ramjet being a BETTER intake for a truck is dependant on its application.

here is a pic of the marine intake as delivered by GM.
http://www.sfatek.com/images/efi.jpg

Just because some Hypertech literature says that the engine can rev to 8000 rpm, doesnt mean much. I would guess Hypertech actually tested about ZERO Vortec 350 trucks by revving them to 8000 rpm, not even 6500 rpm.

I think you are confusing something here.(L31 and an LS1 perhaps??) You just might have the only Vortec 350 truck in the world tha revs over 5800 rpm using the stock black box PCM.
Fastchips Westers, Nelsons, wait4me all can set the rev imiter to whatever rpm they want in the PCM, but the PCM will still shut down the injectors at 5800 rpm MAX.

Guys who have swapped over to the 411 silver box PCM used in the 2001-02 fullsize Chev vans that are powered by the Vortec 350 are indeed able to rev up to 6200 rpm so far.(he didnt want to frag the stock 305.)
The black box to 411 PCM is almost a direct swap electronically, and just use a def. file for an 01-02 fullsize truck.

You need to find someone with Tunercats OBD2 or the JET DST(dynamic spectrum tuner) to copy that Hypertech tune so we can look at it.

peace
Hog

Vortec350ss

iTrader: (20)

Thanks Hog.

-Rob Nap

Lextech

iTrader: (18)

I have a 98 GMC with the 12200411 PCM. I had the stock 4 plug black PCM tuned by F.A.S.T. in Memphis, before I purchased Tunercat, I told them I wanted the rev limit set to 6500. They said they could set it there but that the PCM wouldn't go past 5800, and it wouldn't, it would go into fuel cut.I make NO claims to know what I am doing tune wise but, I purchased EFILive and am having good success so far (except for the crank relearn I am trying to figure out). I have had the engine to 6200 on the stock tach--That's as high as I want to go right now.

julianmwallace

I have the same Hypertech 5002 Superchage/Cam/Headers power module, and on track days I set my rev limit to 6200, but only 5600 on the street. When at the track I adjust the shift points to shift right at what my stock tachometer says is 6000. I'm not hitting a rev limiter and my power isn't dropping off, so I assume it is actually pulling to 6000. Maybe my stock tach is just off and I'm actually shifting close to 5800. But, from what I can tell the stock tach is accurate, so maybe there is something different with the Hypertech 5002 module that both of us have.

Nitrous@LS1Truck

I have a remote phase tach I'm going to install under the hood with the gun inside the truck so I can video this when I have some time for all the non believers. If you like we can meet out at HRP and put my PCM in one of you guys truck if you're will ing to take your truck past 6500 rpm. I don't care what anyone here thinks, the PCM will go above 6000 rpm because I tested it again. jullian, you can't see above 6000 on the factory tach without logging the data but I guarantee if you have the 5002 you're shifting more than 5800. Don't get rid of it because you have something that hardly anyone else has. I was going to sell mine pretty cheap but after all of the 5800 rpm talk it's gonna go for alot more, LOL
BTW, julliane, the 5002 is VIN specific so I'm not sure if it'll work on another 96-97 without your VCM.

PEACE!

hog

I dont know why you would be rolling on the floor laughing about a rev limit problem of the L31 PCM but whatever, you guys are running Hypertech tuning. Hows the torque management?

I really hope its a fix to the 5800 rpm PCM ceiling. I would rev my engine to 6500 anytime to test. It could be a real easy fix for those who need to rev higher than 5800 rpm.

If it works then just set it to 8000 rpm and send a copy of the PCM file to anyone who wants the extended rev limit.

If you dont care what anyone thinks here, maybe you shouldnt post here at all.

peace
Hog

Nitrous@LS1Truck

Ok, ROTF wasn't very nice but I have no reason to lie to anyone here or anywhere else. I just have to prove my point that it'll work just like everyone says it won't. I'm just glad that someone else has the same cartridge like me. If someone says they have something that works and can prove it you ought to give them a little credit. Later

julianmwallace

I'm still not convinced that it atually does rev past 5800, but that is what my tach shows. I really have no desire to turn my engine over 5800-6000rpm, so its not that big of a deal to me. I still have the stock crank and rods, and I don't trust them. If some one is in georgia or south carolina with tunercats II, I would meet up with them. Im from central georgia but race at Carolina Dragway in Jackson.

BIG JON N OL DARKY

For those of you that are looking for more power from your 96- 99 vortec 5.7 engines take one minute to read this. My name is Jon Goodman from Oklahoma and I have had the same problems with my 97 1500 chevy that smoe of you are experiencing. If chunked the 350 and installed a edelbrock headed 385 with a 11: 1 compression.Also used a comp cams XFI Grind with Intake 224/ Exhaust 230/ at 50.Lift is 575". The factory intake and injectors also suck and were replaced with one from edelbrock.Edlebrocks pro flow intake bolts to vortec heads or their E- tec heads like i have.This did require some fabrication and I have not seen it done by anyone else yet but it works and I am open to show people how. I machined my own adapper plate out of 3/4" aluminum to bolt a LS1 throttle body to the edelbrock intake.I had to use Edelbrocks Injectors and fuel rails. The injectors part # is 3853,it is 29 pound per hour.Fast chip in tulsa tuned this beast and it would only turn 6200 even though they told me they deleted the rev limiter.I am now waiting to get my pcm back from Doctors of Performance 616-402-1327 who promise they can get rid of the rev limiter for good.
Doctor of performance 616-402-1327
Fast Chips 918-446-3019
Edelbrock 310-781-2222
"Me" Jon Goodman 580-678-1765

Vortec350ss

iTrader: (20)

Maybe someone with tuning experience should give them a call to see what they say.

-Rob Nap