Look at this thread/picture -

https://www.rx7club.com/3rd-generati...6/#post6412879

There are 2 nipples right next to each other that they have looped with a red vacuum hose. You can use either of those.

Dale

 

This line your have labeled fuel pressure, is that for your fuel pressure regulator? Why not use the port on the inside of the lower intake manifold?

 

probably because I have no idea it existed until now

 

It's down low on the LOWER intake manifold, pointing at the firewall. That's the stock FPR's vacuum source.

Really I think most any post-TB vacuum port is a good source but there ya go.

Dale

 

any guidance on what I "should" set my injection at in terms of starting PSI? My max pressure is my 14psi. Does it matter if it's winter vs summer?

Also, I assume no issues with periodically running window cleaner but staying primarily on water?

 

Just making sure there was not something I am missing. I recently installed an aftermarket FPR. I was not sure if there was some kind of advantage.

 

Or you could run boost juice, minimize the power loss, it wont freeze, and reap the benefits of lower combustion temps as well as knock suppression, and not have to worry about deposits left behind from washer fluid. I order it by the case on ebay. It's not expensive and you know exactly what you're injecting.

 

You would want to use windshield washer fluid because it has methanol in it. The meth is what actually cools you intake temps. The reason you would not want to run straight meth is because it is flammable; anything over 50/50 is considered flammable. Running only distilled water is not going to benefit you much, plus you run the risk of freezing the lines. Boost juice will give you the most benefit because it is 50/50 meth/water, where washer fluid is somewhere around 30/70 depending on what brand you buy. Boost juice really is not that expensive when you buy it in bulk from Summit or Jegs, but there is always the convenience factor of washer fluid.

 

Ah. Interesting. Do you have to tune for it?


@aplscrambles how do you know what you get on eBay is legit?

 

this should clarify a few points …


.

 

So results were what I expected since boost juice has more methanol it it. The takeaway I got was if I don’t tune for it, I’ll be running very rich and I’ll lose some power (which I expected).

@aplscrambles did you ever tune for it or do you just eat the power loss and deal with being extra rich?

 

My only issue with Boost Juice is, it isn't available everywhere, so like race gas, you're ordering it and carting it around with you. If you' re at the track, run out, you can pick up washer fluid anywhere, even a 24 Walmart or something.

 

perhaps you and he both lack discernment; it’s important to separate opinion from facts

methanol is just methanol; how is one better than another other than total percentage?

obviously not; the difference is this, while the injection rate is the same for all, since there’s less methanol in the lesser test fluids that means there’s more of everything else, mostly water. Does it click now? Because even with the boost juice it only matched the non-injected power curve once AFR was adjusted, just with lower IAT. Or rather, despite having lower IAT. 💡 💡 💡

the one thing that was lacking from the tests that would have clarified it all the way around imo is water-only test runs. Despite the different methanol/water levels the test fluids were all cooling down to the same AIT range on the one same nozzle. So you really have to conclude that there’s likely more going on with this that wasn’t perceived at the time the testing took place.

another thing to consider is that there’s likely more ingredients in commercial-grade washer fluid than just water and methanol.

and also when in a pinch, straight water is another consideration though you likely wouldn’t want to run anything other than distilled water except in a pinch, and it will likely cost more power too.
.

 

Gonna channel my inner Dale and say "we're over-thinking this".
At low injections rates a little meth wont ruin your tune, and straight distilled water is still plenty good for what your'e trying to do (freezing concerns aside).

 

it is reasonable to assume that injecting water (?) and mysterious methanol into the motor for the first time might seem to be a bit loony or scary.

if you take a look at the numbers you will see it is quite benign yet will deliver as to cooling in a big way.

consider:

400 rw rotary hp requires 3158 cc per minute of base fuel (gasoline and ethanol, typical "pump" fuel)

energy from the fuel measured in BTUs is 91,972

now let's add 600 CC/Min of Boost Juice or a mix of 50/50 water meth...

300 CC of meth adds 4544 CC of additional energy (BTUs) 4,544/91,972 = 5%....... 20 hp

300 CC of water adds 656 CC of Negative energy (BTUs) 656/91,972 = .7 of ONE %........ minus 2.8 hp

at 400 rw rotary hp 300 CC/Min water is a negative power influence of .007. (!)

of course if you are ramping into boost you are not using 91,XXX of base fuel. if your AI is set to come on too early or ramp too fast the numbers change a bit. that's where "tuning" enters the picture.

further, if you elect to run 100% water... negative BTUs rise to about 1.4%.

400 rwhp... 1.4%... a whopping 6 rwhp...

what a great trade, 6 hp for a happy motor.

in a 400 rwhp situation w 600 CC of AI it is easy to see that if the AI malfunctions the motor will be fine... just tune conservatively and all will be well.

as to Boost Juice V Bug Juice... (i have posted this before)

around 2005 i became aware of a Canadian company, FJO. they had a line of cutting edge AI systems that used solenoids for delivery along with some other helpful items. i ran most of their stuff. they had an inhouse test vehicle, a very big block Camaro with a very big turbo and were making significantly more than 1000 rwhp on pump gas. what did they use as AI injectant? "bug juice." (first time i heard the term.) i asked them about it... Fred Oberbuchner said they had used it for years. yes there was coloring and s very small amount of soap in the solution but there was no ill effect. The Oberbuchner brothers merged w Holley and designed for Holley their hugely successful line of ECUs. i conclude there is nothing wrong with windshield wiper fluid.

not loony, not scary. smart. and no need to overthink

 

My WI only runs in two scenarios: First, It doesn't even run at all in "pump gas" safe boost levels, ie.: up to 15psi, it only sprays to add safety for 16-20 psi settings, so if I'm loosing 5hp to washer fluid vs. boost juice to run a +50hp setting I couldn't otherwise, that's no worry for me. The second is, it'll start spraying at lower levels in the event EGTs get to high, like on track, so its allowing me to run when otherwise I'd need to back out or stop, so a few hp loss isn't a big deal.

 

the intrawebz has homemade bug juice formulas with ingredients like ammonia, vinegar, and such. I know some of the commercial ones have glycol for additional freeze protection. Given that this is being discussed in a thread where two new engines had significant compression sealing issues upon break-in; is it wrong to consider not throwing caution to the wind?, but if you insist then ok.
.

 

Lots of responses here and I very much appreciate the feedback and healthy debate.

To make sure I understand each stance:

@TeamRX8 believes distilled water is fine, but will result in more power loss. Also, that washer fluid may be more than just color, water and methanol (and a little soap) so it's a bit of a risk/unknown.
@Howard Coleman supports windshield washer fluid or boost juice. Either will serve the intended purpose but 100% water will have slightly more detriment on power.
@Narfle and @DaleClark are in the "stop overthinking" and just run it (water/bug/boost) - also freezing isn't a huge concern for me because my FD isn't a daily and don't drive it when it's below freezing anyways.

FWIW, Nelson said for the conservative timing he runs and the boost levels I'm running, this isn't going solve my problems. He said he's tuned plenty of cars with equal boost rates that aren't resulting in bad compression or busted seals even without injection. He said I shouldn't even need AI to keep my motor from going boom.

 

I run windshield washer fluid because of the lower freezing point. Car happens to be outside when it freezes? No big deal. It's not when you DRIVE the car, it's where the car is when it gets really cold.

This is the way I see it. Heat is the enemy of a rotary. Heat warps things and breaks apex seals. Turbos and rotaries make a TON of heat. A simple water injection setup goes a long way towards taking the edge off of that heat, keeping combustion chamber temps reasonable.

Are you going to blow a motor without water injection? Not necessarily. You can blow a motor any time with any setup, period. Sometimes it's just bad luck, bad tank of gas, flaky injector, solar radiation, the price of tea in China, you name it.

I put on water injection, saw my intake air temps drop, makes the car run like it's a cool day when it's a hot day, and my motor is still in one piece 15 years after I built it. Take that advice as you will.

Dale

 

Gotcha. Your advice is always good advice. I was going the washer fluid route but then I saw the post above with the FPR spring that looked nasty and was falling apart so it made me do a double take. Is there a brand or generic you like?


My car is garaged and thankfully never gets below freezing.

 

I use cheap blue washer fluid, my thought being that the fancier stuff has more additives (RainX, etc.) that I don't need, I want the closest to just water and methanol.

Dale

 

Blue washer fluid here as well. @DaleClark Do you use the summer blend or the winter blend? I couldn't find any winter blend this past summer so I have been running the summer blend, and occasionally just use distill water as they go on sale for $1 / Gal all the time.

 

I try to find anything with a less than 32 deg. F freezing point. Sometimes that's hard to find here, up north you have better temp ranges than we do. Obviously the 32 deg. F washer fluid is water and soap, that's it.

Dale

 

a lot of people had no problem with either set of apex seals or the engine builder either, hope the 3rd times a charm regardless

.

 

That's what they are pretty much, this past summer the shelf is always empty for the -20F stuff, maybe I'll stock up a few bottle this winter.