Water/Meth instead of ECU tune?

Basic tech questions such as future setups, different turbo kits, car diagnosis, etc
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Tomakze
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Water/Meth instead of ECU tune?

Post by Tomakze » Tue Jun 13, 2017 10:10 am

Hello all! I am new to the site, and somewhat new to the KA. I have a 1990 2WD D21 that has been in the family since it was new, and I'm fixing it up in memory of its original owner. I used to be a Z31 guy, and so I have a bit of experience with old boosted Nissans. Anyway, I want a very simple turbo setup on my truck for practical reasons. We tow a dirtbike trailer with it and use it for camping, but it really struggles in the mountains (I live in Colorado). So my plan was to toss a stock Z31 turbo on it (T3, internal wastegate set to 6.8 psi) with a very small FMI, and use water/meth to keep FRs in check. I have a complete KA24E from an S13, and plan to steal the intake manifold from that. I don't need tons of power, just more than what I have. (For now, anyway... We all know how this goes.) All the guides I have read so far want me to swap injectors, and I was hoping to avoid that by using water/meth.

I want to know if this is a good plan. The goal is to get good MPGs (hence why I don't want to change injectors) and have some positive intake pressure for pulling a trailer at high altitude. As well as making it more fun to drive, of course.

A buddy of mine has a gen 1 Neon with a built motor (12:1 compression, crazy cam, piggyback ECU, long tube headers, etc, etc.) That revs to 7600 RPM, and he runs it on pump gas thanks to water/meth. I kinda want to try it out myself.

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Re: Water/Meth instead of ECU tune?

Post by ICEMAN.KCMO » Fri Jun 16, 2017 1:26 pm

Go with at least 370cc injectors. I would recommend using the S13 wiring and ECU. Tuning that is a breeze. just need to socket the ecu to accept a chip. Easy to tune.
Steve.

Tomakze
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Re: Water/Meth instead of ECU tune?

Post by Tomakze » Sat Jun 17, 2017 6:02 pm

Easy enough, I have all of that! But you think I will still need to swap injectors with less than 7psi and water/meth? I was really hoping I could avoid that.

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Matt Cramer
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Re: Water/Meth instead of ECU tune?

Post by Matt Cramer » Tue Jun 20, 2017 9:31 am

Tomakze wrote:Easy enough, I have all of that! But you think I will still need to swap injectors with less than 7psi and water/meth? I was really hoping I could avoid that.
If you want to optimize your fuel mileage, you'll need something capable of fully tuning the timing correctly anyway - simply backing off timing by rotating the distributor will ruin your off-boost timing and fuel economy, and just leaving the distributor where it is won't be good for the engine. And if you put a proper tuning option in there, the larger injectors won't hit you with a mileage penalty on their own. Sure, they will allow you to feed it more fuel under full boost, but it's cheaper to burn gasoline than aluminum...
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
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Re: Water/Meth instead of ECU tune?

Post by p00t » Sun Jun 25, 2017 7:08 pm

I'm with Matt on this, learn to tune a little and the injectors won't hurt your MPG at all. Actually you will gain MPG with a little dyno time to dial in your cruise timing and AFR!

Edit: Forgot to mention that you are cruising in top gear 90% of the time, so that's where your MPG concerns are.
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Tomakze
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Re: Water/Meth instead of ECU tune?

Post by Tomakze » Mon Aug 07, 2017 5:40 pm

Apparently my email subscription isn't working, I had no idea I got more responses!

Okay, I have the s13 ECU, so I will look into socketing it, and I will probably go with bigger injectors. I just did some trading, and aquired my "free" Garrett T3 turbo for this project. I am hoping to keep this fairly cheap, but it needs to work well enough to be a reliable daily driver and tow vehicle, so that is much more important... As you say, gasoline is cheaper that aluminium! Bahaha!

Thanks for the responses... Now that I have the turbo in hand, the real research must begin!

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