I would like to swap to OBD2 since I have heard of a few people on here turning LT1's to 7200-7300rpms. My OBD1 setup will only turn 6900rpms on the dyno so if I could get another 300-400rpms it would really help to be able to cross the traps @ 140+mph, with 225+N2o that I plan on spraying soon. I just bought a dynatech opti from SSimposter since hes going to an LS1 PCM conversion. I am running a 96-96 timing cover already, an OB2 PCM should be cheap and I am going to get the car dynotuned anyways since I swapped to a singleplane intake. Who has swapped a 95 LT1car from OB1 to OBD2? LMK Thanks Clint

 

There is no difference between OBDI and OBDII PCMs as far as RPM capability is concerned...both do not have fuel tables past ~7000 RPM.

Honestly if you're looking at turning 7300 RPMs you are limited to the EFI Connections 24x system, or a FAST stand-alone.

 

I hear what you are saying but something is different b/c I have heard of quite a few people including Ed wright turning LT1's above 7krpms. Has anybody else verified with an aftermarket tach that they can spin any higher than 7k on the stock PCM?

 

Well if you are doing a LS1 PCM conversion, if you get the later LS1 PCM, I think you can spin it to 7200.

 

From what I understand in speaking with Bryan Herter directly, you CAN spin them past 7k, but the PCM doesn't have the ability to add more fuel past 7k. In other words, the PCM will stay in the last cell. You might be able to get away with 7100, but anything after that is a risk in running lean - something you don't want to do at 7100 rpm.

 

LS1 PCM is tunable to 8000.

 

Ok, I am not running the LS1 PCM here but does anybody have any experience swapping from OBD1 to OBD2? I remember Frank95z swapped his 94 over to OBD2 b/c of the stall problems with OBD1cars. Well I guess I will just stick with my small solid roller and 6900rpm limit for now. Thanks anyways

 

Where did you get that bit of information?

 

The stall wall problem has been fixed for 9 or so years now. So it's a (fortunate) non-issue. But man did it SUCK! That was probably one of the most beneficial PCM fixes for the LT1.

 

This. You can squeak a few extra hundred rpm on the last fuel table.

 

An article from aug,07 high tech
Ed wright is using FAST xfi
Rick abare has Holley Commander

Ultimately, high RPM is needed to achieve the ETs we are searching. Ls1 pcm conversion,FAST XFI,Holley Commander,Accell DFI are the only ways to get there safely. The opti set up is awesome but it has limitations and hi RPM dependability is the case. Some say the stock opti can function at 7200 rpm and a few have proved this.......The Lt1 pcm has seen the same type of RPM but again it should not be trusted at this RPM or past...Taner had pushed his to these limits many years ago as well as a few others.....

 

Well i talked to Ed wright himself and he told me "Some run up to 7200rpms some shut off @6900-7000rpms just depends on the ECM. I have another so I will try programming it to see if I can get to 7200rpms. later

 

In your situation I would SERIOUSLY consider switching to LS1 ignition.

How long do you think an opti is going to last winging to 7200+?

IMO it would be ludicrous to spend money on switching to OBD 2 and still keep the lt1 pcm. It does the job usually but the lsx stuff is so much more advanced. I would bet you would gain power all the way through as well by being able to have better control over the tuning.

 

If I had more money to spend and would plan on turning over 7500rpms I could see switching. I am just staying OBD1 and keeping my smaller solid roller since it peaks around 6600-6800rpms. I have seen back to back dynos from stock PCM to Fast EFI and no gains were to be had, if everything is tuned correctly. If the LS1 pcm tuned itself thru the 02's I would be all over it LOL but you will get the tuning done quicker with the LS1 PCM but not much more. I will probably swap over next year but for now going with the dynaspark setup. Later

 

will the pcm pull past the 6900 rpms and just start leaning out.. Or will it pull to 6900 and hit a rev limiter.

 

6900-7100 RPMS THATS ALOT OF REVOLUTION PER MINUTES

 

My car just hits what sounds like a rev limiter@6900rpms. Ed told me to try a few different ECM's and if your lucky they might go to 7100-7200rpms which is what I would like. Later

 

yea from what i understand theres some "freak" pcms that will let you spin a little higher. fwiw, i got my dfi setup for less than the efi connection harness alone costs. theres deals out there on the accel stuff. i just figure why dick around at 7k when theres 50 hp waiting up closer to 8k, and you can get there for less than 1000 bucks.

 

First off, do you really need to spin the motor past the 72 mark? I mean you did check it and it is making power up and past that point? The reason I ask is because I have had so many customers with setups that the shop/builder say it should make power up to 7000+ when they were all over with by like 6300 or so. I am talking about motors with very large cams, heads ect. even solid rollers. Also on the OBD1 PCM's running up to 7200 RPM's, I have never had one that didn't go past that. Granted is was only a few but I never had one that hit a so called rev limiter....

 

I would definately go with a used Accel or older Fast setup but just don't want to spend another grand on the car right now. I would definately do my own harness v/s buying the efi connection. I sold my opti for $150, it was new to a friend and I bought a dynaspark for $375 from a board memeber so it only costs me alittle to try this. Ben went 9.90 on the stock PCM with a dynaspark so I am trying that route now. later Clint