Water Injection - EGT Pre/Post Turbo/Necessary?

[BlazedGlory]

I am currently installing a water/methanol injection kit on my built SR. I run a Power-FC (L-Jetro - Z32 MAF), Datalogit, and an Innovate LM-1 wideband. Without the water injection, I tuned my AFRs with the wideband, and I basically tuned the timing map with the knock sensor as a guide.

I don't feel quite as comfortable tuning the timing map with water/methanol injection, but I'm not sure if an EGT gauge would be beneficial or a late warning. Further, if I did install an EGT probe, I would feel uneasy putting it in the manifold pre-turbo. I know it wouldn't be near as useful mounted post-turbo.

Should I just tune the way I have been, or would EGTs be a very helpful thing to monitor?

[prodigy212718]

I am considering adding water injection on my rb too. Running into the same questions. I thought the point of water injection was to lower combustion chamber temps in addition to protect against detonation?

[adictd2b00st]

you don't "need" an EGT gauge but of course it wouldn't hurt either. there should be a pretty direct correlation between your wideband readings and the egt anyhow. when you run leaner your also gonna run hotter. so in that sense i wouldn't say its absolutely necessary.

fwiw i ran methanol/water injection on my rx7 tuning off a wideband..... i had an egt gauge too but only really used it to keep an eye on things after the fact

[slider2828]

Water or whatever injection has the same effects as increasing octane in your gas basically from what I read at Snow Performance or water mist (or something)... It doesn't have a direct correlation, but the engine should be tuned when it is used.

[BlazedGlory]

I am considering adding water injection on my rb too. Running into the same questions. I thought the point of water injection was to lower combustion chamber temps in addition to protect against detonation?

Yes that is the point, but because of that fact it allows you to safely pull the fuel and add the timing back in that you pulled to avoid detonation..

[BlazedGlory]

you don't "need" an EGT gauge but of course it wouldn't hurt either. there should be a pretty direct correlation between your wideband readings and the egt anyhow. when you run leaner your also gonna run hotter. so in that sense i wouldn't say its absolutely necessary.

fwiw i ran methanol/water injection on my rx7 tuning off a wideband..... i had an egt gauge too but only really used it to keep an eye on things after the fact

Wouldn't your timing effect your EGTs too?

[godzillarb]

Further, if I did install an EGT probe, I would feel uneasy putting it in the manifold pre-turbo. I know it wouldn't be near as useful mounted post-turbo.

Should I just tune the way I have been, or would EGTs be a very helpful thing to monitor?

I agree with the above posts about the EGT gauge not really being required for your setup. However, I've installed 3 or 4 EGT probes pre-turbo and never had a problem. A lot of diesel guys run this way because going post turbo totally defeats the purpose IMO. Readings will be low and slow to respond. On my diesel Jetta I've had a pre turbo EGT probe installed for 30,000 miles with no problems yet.

[GSXRJJordan]

You're correct that if you did run an EGT probe, it should be pre-turbo (most guys with stock intake manifolds put them in the 4th runner, because cylinder 4 will be the leanest - supposedly). Everyone also is correct in that you don't really need it, because the wideband is reading the same thing.

I agree with you that you should get it tuned by a real tuner - with and without the water/methanol (hopefully you've heard about using windshield wiper fluid). That's the only way you'll a] get the most out of your setup, and b] have the peace of mind you need.