Well, I finally got around to getting the ECM tuned for my 97 LT4 Firehawk and all I can say is WOW! A big thanks to madz28.com for a great tune that was right on the money the first time. I went with his OBDI conversion package so I could keep the stock ECM for future collectibility and also so I'll be able to use the cheaper/free tuning/monitoring software. Total cost was $225 for the conversion, and took about 5 minutes to swap out ECMs.

Now on to the good stuff, the car picked up 20RWHP and 17lb-ft over the previous baseline. Peak numbers are now 300RWHP and 317lb-ft of TQ. There is a noticeable improvement all the way across the range, and we also raised the revlimit to 6500 vs the stock LT1 ECM limit of 5600. It really doesn't need to go past 6000, but it is interesting to see that at 6300 it's still making over 280RWHP. I think we might still be able to gain a little more at the top end from looking at the A/F Ratio, but I really wouldn't expect to gain more than another 5HP maybe. Also, this is with the stock 97 LT1 knock sensor and while there isn't much indication of knock retard, I think there might be a little going on from 4700-5600 where the HP graph dips a little bit. I'll have to get an LT4 knock module and see if it makes any difference.

Once again a very big thanks to Ion at Madz28.com, if anybody needs any tuning, definitely give him a try.

 

SHEEIT!!!! You picked up 20rwhp just from a tune job???? Awesome job Ion. I threw all my stuff together at once so I'll never be able to know which mod did what. But I can live with it. Congrats on the score dude.

 

I think im am pretty much set on having Ion do my tune. I think thats the only thing thats not covered besides the lt4 knock module as far as computer performance goes. All I need now is the moolah lol.

 

I knew there was going to be a pretty big jump since they used the stock LT1 ECM and fuel injectors on the LT4 cars, but it is really amazing what a difference it makes. It definitely points out how important tuning is when you do heads or a cam on a stock LT1.

 

I will know the feeling soon too

My tuner, Dave, did a good job on the tune but the car was pulling 15 degrees of timing..
Just did heads and a bigger cam. Car spins the drag radials at 4k and up in 1st gear full throttle 3.42 gears on the M6.

After finals week i'll have time for my friend/ local tuner to tune it out.. Im guessing the car has around 400 fly wheel hp right now... should have 40-50 more horses after zeroing out the timing and leaning out the fuel some (running alittle rich).

 

Shouldnt your car already have a LT4 KM?I would think so.

 

No, the LT4 SSs and Firehawks came with stock LT1 injectors and ECMs due to certification reasons. It would have made sense to at least change the KM to the LT4 unit, but I checked the part # and it's definitely an LT1 KM.

 

Ok,I thought that was why they made them.Also,I thought they got bigger injectors,like 28lbs....anyhow nice gain there..

 

just curious , did the tune improve your idle ?? mines at 850 and it idles a lil too strong I feel . The guy who had it before me upped the timeing and idle to made it idle well (too bad he didnt give me whatever he used to do this with) . itll drag me to 30mph .
thanks , Justin Linett

 

Mine has always idled just fine, but then mine is an actuall LT4 which doesn't have the Hotcam (yet).

 

Thanks for the good words, Evan. The numbers are definetely very nice and I won't even say anything about the car....

 

Wow....That is a very nice gain from a tune on a stock car. It looks like you were running really rich before. What do you get when you do the obd1 conversion? Because thats what i'm thinking of doing.

 

Nice results.

 

great work madwolf! too bad an LT1 couldnt see a 20 rwhp increase over stock with simple pcm tweaks.

 

Thanks.
On a properly running LT1, 13 RWHP is no problem. Usually about the same if not more RWTQ too.
So I still think tuning is a pretty good and cheap mod regardless of what people say... (wait until you do more mods).