water/meth injection in stock smic for reliability.
 

I'm not very familiar with water injection although I understand how it works.
I would like to add water injection as means of reliability to ward off the knock demons. I understand that in a stock fd I shouldn't need it but I figure, if done right it can't hurt. Would the stock ecu be okay with this?

Absolutely.

You would want to keep the spray amount down, but it would be a good safe guard.

Agreed with Vicoor. A buddy of mine in the UK did just that. He added a small nozzle after his IC and ran that on his otherwise stock car. Never missed a beat =)

Bump old thread but I'm considering this exact thing right now although my tuner is adamant that I don't need it if I'm only looking to run 0.8-0.85 bar (11.6-12.3 psi for the Americans) on a car with the following engine spec for a 1999 Mazda RX-7 Type RS. Keep in mind that this is a 280ps (276hp) car and boost from the factory was 0.74 bar (10.75 psi) as opposed to older models that ran 0.62 bar (9 psi).

1. 99 spec twins running sequentially
2. stock airbox with air guide (intercooler sealed off on later models)
3. stock intercooler with stock sealed duct
4. Knight Sports twin tube downpipe
5. Stock catalytic converter and pipe
6. Fujitsubo 3" cat-back exhaust
7. NGK 9's spark plugs
8. Koyo N-Flow 48mm radiator
9. Apexi Power FC

I'm hoping for around 300 brake horsepower or thereabouts on this set-up, but the numbers aren't what I'm that concerned about as what I'm really after is a reliable configuration for 10-12 track days per year in the UK (weather never gets hotter than about 80 degrees in peak summer) whilst preserving the 99 spec turbos for as long as possible (hence why I'm choosing to not run more boost).

Before the recommendation from my tuner that I don't need water injection at this level, I had purchased the AEM V2 water injection kit and was going to hook it up to the throttle body elbow as an element of insurance to keep intake air temps nice and cool just in case the stock intercooler becomes overwhelmed on track for some reason. Specifically, I don't want my tune to be predicated on the water injection since I just want to inject a minimal amount to cool the intake charge and in the instance that the water injection failed I don't want to run the car running lean at the wrong time.

But, in light of my tuners insistence that the stock intercooler is fine I just wanted to get your opinions about whether you agree with his viewpoint or not. It's not that I won't install the water injection anyway but more to the point of when is the stock intercooler no longer able to keep up with the demands of modifications?

I note that the RX-7 with the stock intercooler won several races in Australia in the Bathurst race series and it also won a rigorous endurance test in Japan on Best Motoring when going up against rivals such as Evos, Subarus and Skylines.

Stock is fine if your temps (oil, air, water) are in line. If they get out of line, you will need to make changes to get them in line and if you track it, they will probably get out of line. Also need to monitor AFRs to ensure you're not running lean.

IC may have been stock, but I bet there were other non-stock parts to keep the temps down.