808, 424 or 531 ecu for V6 race car?

[Gareth]

Hi all,

Been thinking, my speedway car has a V6 ecotec with a 531 ecu, is there any benefit to running a map based ecu over the maf?

Some of what i think are pros to map -

- no maf (intake restriction)
- car works in a dirty environment, maf gets dirty easy
- ability to 'self tune' with a wide band hooked up
- eaiser for tuning novices like me to understand

And the cons -

- less accurate
- shit, temperamental ecu (808 anyway)
- no aldl tuning (808)

Looking for any thoughts on this please

Also, why is the map based IAT in the manifold and MAF one in the intake tract?

[Dylan]

I may be reading this wrong but the 808 does have wide band self tuning and ALDL tuning.

[Jayme]

808 shit and tempermental? maybe you are jsut lucky enough to see the bad ones? haha. anyway 808 can be modded to have aldl.
self tuning.... yeah dont. just tune once and leave that alone.
I agree on the dirty maf, gettiing rid of that as a restriction and a failing part due to dust is reason enough. also on a speedway car, the sequential injection means little as you only care about outright power, and at WOT the sequential means nothing anyway, so going back to a batch fired MAP based ecu is not a worry.

next biggest reason is throttle response, its way better on a map ecu.

as for temp. in a map it is required as a part of its VE formula. air pressure in intake and air temp in runner as air is passing into cylinder. different runner temps have different amounts of air into the cylinder even tho the pressure in the manifold may be the same, as the temperature indicates density.
in the MAF it needs to know the grams of air at the MAF AND the temp of that air at the MAF, to know how much air is passing into the engine. because its been measured at the MAF, it doesnt need to know the temp at the runner. only one place the air can go from there - into cylinder!

[Dylan]

Anyone ever moved it into the runner on an LS1 with mafless set up?

[vlad01]

808 or 305 hands down.

[Gareth]

I may be reading this wrong but the 808 does have wide band self tuning and ALDL tuning.

yes that is correct, you read it wrong, that is a pro

808 shit and tempermental? maybe you are jsut lucky enough to see the bad ones? haha

must have these have caused me heaps of issues in the past

This is the application for those who are interested

[Gareth]

as for temp. in a map it is required as a part of its VE formula. air pressure in intake and air temp in runner as air is passing into cylinder. different runner temps have different amounts of air into the cylinder even tho the pressure in the manifold may be the same, as the temperature indicates density.
in the MAF it needs to know the grams of air at the MAF AND the temp of that air at the MAF, to know how much air is passing into the engine. because its been measured at the MAF, it doesnt need to know the temp at the runner. only one place the air can go from there - into cylinder!

Sooo, I'd need to relocate the IAT to the manifold? And if so does it need to be in a runner, could it just be in the plenum?

[Jayme]

most of the ones I do, I find it works fine in the plenum... it may even work in the stock location, im only going off things ive heard, with a few assumptions added in.
my general thinking is if GM did it that way, there must have been a reason lol.

you will have to use the IAT sensor off a buick engine, as they are different. just drill and tap into the side of the plenum and screw it in. only one bloke I know actually went to the trouble of removing the lower runners and putting it in there, and it doesnt run any different to the ones that have it in the plenum anyway. I assume you would just calibrate the inverse temp table a little bit differently to do it properly (but I didnt). also need a buick or v8 coolant temp sensor. one is bigger than the other, cant rememebr which, but neither will screw in, you will need an adapter.

when you go to tune it, done use any buick spark maps as a base.... the VR v6 has the least timing of all MAP based tunes and even that is too much timing for the humble ecotec!

[Holden202T]

yeah I agree with Jayme, when I did the ecotec to 808 I put it in the plenum just behind the throttle body, in the early motors its blank, in the later ones was used as an EGR port, it maybe saw too much air there, im not sure, it seemed to work ok.

I've also made a 808 tune for ecotec with 808 (in the custom tunes thread), it has timing and fuel adjustments for a Ecotec with high flow cat and 2.5 inch exhaust, should be a good starting point for your setup..... it has the map switch also for 91/98 octane fuel.

the info on the conversion is here http://pcmhacking.net/forums/viewtopic.php?f=16&t=144

best I could find of the CTS

P1020596.JPG

and the MAT

P1020150.JPG

P1020151.JPG

having a dyno and such definitely go the 808, tune to suit your motor and it'll be sorted then and will be much better I reckon!

oh and is it just me, but I can't help but laugh at the "pull off" sticker on your kill switch

[Gareth]

but I can't help but laugh at the "pull off" sticker on your kill switch

Yeah, I cop a bit of shit about that, lets just hope that the crash crew is a female
Everyone else seems to still run some sort of electrical kill switch on the outside of the car (I have seen plenty of winning cars loose because a back marker has shut their car down with a rock.. ) So a cable down to a key type isolator switch is the go I recon, but you have to label to switch action.

Thanks heaps for the photos 202

Why is the throttle response better on a MAP based system?