Drawthrough & Meth/Water Injection
 

Hi all... I want more boost!!! :nod: But, I want it safely.

My current setup is pretty much listed below in my signature... I'm curious for maybe examples of what I should do to my timing and boost psi after adding meth/water injection AFTER the turbo.

I'm currentlly running 7psi and would like to target 1 bar (~ 15psi). I have my dizzy locked at 10* leading, 7* trailing.

Looking for ideas on boost psi and possible timing changes.

Thanks Guys!!

NOTE: This is a DRAWTHROUGH setup... please know the difference in a draw- and blow-through setup before commenting... IE, no intercooler!

Here is a link to my original build thread:
https://www.rx7club.com/1st-generation-specific-1979-1985-18/12a-cartech-drawthrough-help-814461/

You might find better answers searching through the 2nd/3rd gen sections. Other than that, I'm no help.

Do you have any way of monitoring air temps? That would be the main limiting factor I can see for this setup. Meth and water will definitely help you out as far as detonation and keeping air temps at bay. I would run the nozzles as close to the turbo as possible to maximize air temp cooling. As far as timing goes, I'm not not real experienced with the older engines but as long as the intake temps and afrs are safe I imagine a max of 13* or so at 15 psi would be fine. Or you can keep it where you're at to stay on the safe side.

Yeah, the reason I started this thread in the 1st Gen section is because my turbo setup is rather unique to a 12A AND all them 2nd/3rd Gens are running INTERCOOLERS...

I understand that, but the other gens have more experience with meth/water injection and I've run across a few good threads on it in the 2nd gen section. Having an intercooler doesn't change the basics, maybe just the placement of the injectors.

Maybe I'll look into it Trochoid.... It's just I don't know many 2nd/3rd gens running drawthrough :scratch:

But, maybe i can find some BASIC UNDERSTANDING of what's safe.

I just wish someone out there could answer my question right off... can I run 15psi boost WITH meth/water (50/50) injection on N/A rotors (9.4:1 compression) with locked timing at 10* and good AFRs......

Anyone? :scratch:

The key to making more power with meth is in the tuning. It allows you to change your fuel curve and add timing. Just adding meth/water alone without changing tuning will not make any noticeable difference. Now for the risk factor: if you tune for the water / meth and your bottle runs dry, your gonna be running too much timing and too lean on fuel so you really gotta watch your levels. I run the snow performance kit sparying my lower intake belwo the camden and have been very pleased,

I think he also plans on using the water meth not just to make a little more power, but for a way to safely increase his boost level, like double it. So a re-tune is in his plans. So I guess we need to know how to know how much boost he can safely run with the meth as a cooling aid.

I'm guessing that using an egt gauge and air intake temp gauge might help you know how you are doing. I couldn't tell you what intake os exhaust temps to aim for though... you could monitor the temps, then bump up your boost incrementally till you hit your 15 psi goal.

I don't know about timing though.

I have no experience with this btw, I'm just trying to brainstorm with you...

Yes.. I plan on making more power... Tis the point. I am thinking of adding meth/water injection as a detonation prohibitor/intake temp reducer/octane booster... I am targeting 15psi (if feasible). Yes, I will be re-tuning carb to maintain AFRs. I DO NOT have an EGT probe or intake temp probe... I had just planed on tuning using my wideband AFR......

For the concern voiced about "if you tune for the water / meth and your bottle runs dry, your gonna be running too much timing and too lean on fuel"... the system I am interested in has several safeguards including low fluid levels, plugged jets, insufficient flow, etc... The system would shut off if any of these happened and I will be setting up my electronic boost controller to respond to this and kill boost.

OK than.. now that we have that settled :nod:

Big difference between you and me is the "control", you can at least control you boost. With a standalone in the future you could react to everything, but good start none-the-less. For me, no control, just monitoring.

Cheaper in the long run to go blow through. Just my 02

I -cough- appreciate -cough- your $0.02, BUT, I'm already running a drawthrough sooooo your comment does me absolutely no good :egrin: :icon_tdow

There's still love.... I just thought this would be easier to figure out.

I've been looking ALL OVER the forum (3rd/2nd gen, single turbo, etc) for similar setups with no luck :(

*cough cough* um...... Yeah....... Will you just go with a FD motor already!

Just a suggestion but you might check the timing maps posted in the engine management forum. What management system are you running?

yeah less headache's :lol:

i would get a egt and ait sensor etc only way your gonna know whats safe. and do small increasements.

I agree. You really need an iat sensor of some sort with this setup. Extreme intake temps will cause the fuel to auto ignite. Coupled to the fact your compression is high and your engine wasn't designed to be boosted. Turbo outlet temps can easily exceed 250 - 300 * F. Without an intercooler you're heavily relying on the water and meth to do your cooling. If you can't get intake temps down to around 125 you're going to have issues. I think it can be done, but you need the proper tools to monitor what's going on. If I was to pull a number out of my head on how much you need to inject I would say a minimum of 1000cc/min. I suggest mounting the nozzle preturbo, this in my opionion is the best way to go.

I would go post turbo, you need to cool the charge not the turbo. This drawthrough set up must work much like a camden as far as heat goes yet product a turbo like power curve with power climbing in upper rpms instead of leveling off.

stock ignition, MSD coils, locked timing 10* leading 7* trailing

been a while sense last post... looking for timing and boost psi suggestions WITH meth injection.... anyone?

I'd suggest switching to blowthrough or fuel injection :) I always kept the timing conservative on my blowthrough setups, about the same as what your running. If you don't have an intake air sensor get one or two and watch the temperature as you increase boost. Run as much boost as you can and still keep the IAT reasonable. If you can't increase boost much, then play with the timing and AFR some on a dyno.

have you been to the aux injection forum on here? I believe either BDC or Howard Coleman ran no intercooler turbo'd, which functionally would basically be the same as your setup, minus the tech. As far as I've read their car worked really well that way, but not ideal. I think they were running upwards of 20psi with no intercooler, just a ton of water/meth. You really should track IAT somehow, but barring that, most research suggests that you can run injection in lieu of an IC.

Go to aux injection, there is a TON of info there, skip the 2nd and 3rd gen forums entirely. Bottom line though, add your meth and water and tune the car as if it wasn't there (up your boost, but stay conservative on your timing and AFR) and you'll have a good safe tune (IAT's allowing of course).

Meth and water will allow you to tune the car much more aggressively, but my opinion is to just run the extra boost the injection allows, while tuning as if no injection was taking place (for example: where you could run 12:1 AFR at WOT with water/meth, keep it at 11:1 as if you didn't).

thanks for the info guys....
I'm currently running ~10*L and 5*T LOCKED timing and 10 psi boost...
My question is can I run more boost and/or timing WITH meth/water injection??
The answer I feel I'm getting is NO... that the meth/water injection just makes everything more safe.... please correct me if i'm wrong.

"YES", I increased boost "and" timing with my meth injection on my camden. A snow performance kit is costly but at least you have control and can install a nice big warning light in case the sensor does not detect flow from the pump and you can install a warning light for the tank reservoir as well. Would be great with a stage 2 boost sensitive progressive controller.

If you read my response or went to aux injection you would already have answers to these questions. We can't tell you what actual timing or AFR's YOU PERSONALLY can run on YOUR engine as that is different with every engine/location/set up and a very personal issue that needs to be professionally tuned.

What you can learn for yourself is that yes injection allows you to run MORE BOOST, MORE TIMING, and LEANER. I simply suggested not taking advantage of all of this in the interest of safety. The weak point of an IC-free setup is intake air temps, but injection helps those too, especially meth.

I guess I was looking for experience with people who have used DRAWTHROUGH or SUPERCHARGED setups and meth injection... I just don't know what's safe... 12psi? 15psi? 30psi? (lol)
This will all be on a fresh 12A motor... 9.4:1 compression, end plates street ported and intermediate plate "mild" bridge port, all fresh seals with wideband in place. Meth injection nozzle will be installed RIGHT at turbo outlet before entering intake manifold.

This is what my setup looks like:
https://www.rx7club.com/attachment.p...2&d=1233377335
https://www.rx7club.com/attachment.p...3&d=1233377335

And installed (early install before new motor):
https://www.rx7club.com/attachment.p...8&d=1233463617
https://www.rx7club.com/attachment.p...9&d=1233463617