Bens3rdgen

I was hoping to get some info on engine management. I'm planning on putting a 348ci forged LSX into an old carbed car. I'm planning on using a GT-78 to make around 850HP, it will be a road race car. From what I've read a 2/3bar MAP system is the safest to use. I think there are a lost of guys still using there stock PCMs but what years are best? What do you use to to change the tables. How much did it cost and how easy is it to use.
I've done a lot of tuning or early 90's cars but no 98+ OBDII stuff. Thx.

Ben

Spenser309

if your gonna do the stock pcm, go with a 99+ setup, 98's had a different PCM and wiring.

sr71

iTrader: (17)

don't waste your time with a factory pcm on a race car. go for an aftermarket system. you will thank yourself later.

Bens3rdgen

What are the specific advantages of an aftermarket system. I thought they were pretty expensive. Which ones would you recomend. Thx.

427

iTrader: (3)

If the stock system is used a 99+ F car with HP tuners 2 or 3 bar map option and speed density tune would work well.
A BS3 will be simpler to use and simple to hook up. The unit that would run your engine would be 2,200.00 with all the ability's of the factory system +some. MSD will be marketing a gen 3 cop system that has a 1,000.00 price point, but it has bank to bank injector control and no individual timing control. It is more for a entry level system, your power level desired would suggest the individual control would be useful for you.

Kurt

Bens3rdgen

Just to make sure, the stock system has bank to bank injector control and no individual timing control, right? What is the difference between the vette and F-cars PCMs.Thx again.

Reckless

iTrader: (9)

The factory PCM is sequential but has no provision for individual cylinder tuning.

Spenser309

batch vs sequential isnt really that big of deal. One of the highest Hp cars on this site runs a Batch system. Main thing with a batch system is everything better be exactly alike for all the cylinders. So basically stock heads, different flow rate injectors, and the like wont fly. But why would you use thoose anyways? Iono, im slightly biased because i do like the MegaSquirt(there comming out with sequential).

Anyways, unless you want to really make an electronic board from scrape and then modify it for your application i'd go with the bs3, stock pcm, or even that new MSD thing sounds good. personally id go with the cheapest one.

BTW: Im not a sponsor, I dont sell anything, im just a kid who reads way to much about cars when hes bored.

DeltaT

iTrader: (5)

To really get any benefit out of 'individual cylinder tuning', you need to be set up with 8 EGT probes (or 1 than you can move around with the right set of drilled headers), a Mustang dyno and a decent amount of time. It's really only to get the last 5-10% out of the motor, and the tuner really has to know what he's doing.

If you apply the 80/20 rule, you'd get more than 80% out of the motor for only 20% of the tuning time & expense, if you stuck with batch or staggered batch mode.

Jim

427

iTrader: (3)

The Corvette has a fly by wire throttle system.
Some additional things to consider. When using seq control you get greater idle quality/drivability than batch fire, this is why the OEM's use it. This really becomes useful if your injectors are larger than stock.
In batch fire high power cars, or any system that cannot adjust individual cylinders you need to tune the engine for your lean hole. That leaves power on the table in the other cylinders. In my personal nitrous racecar I had a troubled cylinder that I found the hard way(burnt piston). When I repaired the engine I added fuel to cyl5 and took out 2 degree's of timing to keep the cylinder alive while still running the others hard. The gen3 engine has shown some problems with cyl 7 in our high power engines. With a BS3 we can keep that cylinder alive without handicapping the rest of the cylinders.
So the choice really is up to the use of the car and the ability of the ECU. If your racing is limited to track day fun/race and you are willing to work out the factory ECU/HP tuners, it is a very powerful control that runs seq.
If you need to get all you can from your set-up and want added features to tailor fuel/spark in a simple package than the BS3 is tough to beat. I do sell BS3 and HP tuners. I sell them because they are the best we have tested for ability/cost.


Kurt

Spenser309

427 is right but is it worth 1,000 dollars. Especially when you can run all the cylinders richer and make near 95% of the same power.