E40 ITB tuning

[Ricardo]

I have a 2007 Chevy Colorado running an F Body LS1/T56 combo off an E40 PCM with an SSR modified tune.
Everything works fine, all instruments and gauges, warnings, etc.
I also have an ITB setup that I have wanted to install since day one on this combo.
Is there a workaround in order to tune an ITB setup for this?
Unfortunately there is not an option for the E40 PCM like the AlphaN adder for the VE table in the enhanced operating system offered for the 411PCM.
Anybody done ITB?s on a E40 PCM that could share some advise?

Thanks for looking

[edcmat-l1]

What ITB setup? No common plenum?

[Ricardo]

Racehead Engineering from Australia.
Not a common plenum at all, just an aluminum block where you locate the MAP sensor and the IAC (if doing DBC) and obtain a vacuum signal for the Brake booster. The 8 TBs are connected to this block by a 5/16" hose arrangement.

[blindsquirrel]

screenshot.23-02-2024 20.12.24.png

[ns158sl]

I think I would start by figuring out the combined TB area and plugging that into ETC scalar. Not perfect but I don't know why it couldnt be done. ITB's are sweet.

[blindsquirrel]

ETC scalar is nothing to do with it. There is no MAF. There is a MAP, but it depends on a clean reading of manifold pressure to work right. ITB does not have 'manifold vacuum' in the conventional sense, it has pulses. Attempts to average all the individual runners together with tubing doesn't really work, because when one cylinder is on the intake stroke the other 7 aren't, and those other 7 are at... some pressure other than vacuum. Some are seeing a high pressure spike from the reflected wave, some are just plain open to atmosphere...

[ns158sl]

I dont know why i never thought of it that way lol. Makes sense why he said something about AlphaN. Id still bolt it on and see what happens lol. I mean, you could run 8 MAP sensors and wire them to gain an average/mean output ? Totally not sure, just anything to make ITBs work, im in.

[blindsquirrel]

Yeah, how hard could it be, right? Birds fly all the time so I should be able to too if I just flap my arms hard enough. Logic!

ITBs and EFI are definitely doable just not with the wrong ECU, which the E40 (or any factory box, really) definitely is.

[edcmat-l1]

I've tuned many ITBs going back close to 20 years now. I did several of the earliest Harrop setups. I've had people bring ITB cars to me from states away. You can contact me through my email in my sig if you need help.