Pre Turbo Injection - How Much and When to Inject

[parmas]

Originally Posted by Flr Power

Are you sure you're Wideband is accurate?

I have two wideband sensors. One wired directly to the haltech ecu and another independent AEM wideband gauge. Both showing same readings.

How did you measure the power change with different AFR?

I do not have a dyno neither have the money to tune it on a dyno for every upgrade I made to the setup. I tune on the mainly on street and adjust for the grip on track.

I measure power by time vs speed on 4th gear.

Full throttle from 2Krpm and check how much time it got to same rev limiter or 140km.

Also power and torque is easily felt on a small car like a yaris

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[parmas]

Originally Posted by rotrex

Are you sure your reference position for ignition timing is right?



Any modern engine won't take 40 deg timing at anything but low load.
Typical numbers for NA engines past 3000 rpm and WOT are 30 to 34 deg.
Add boost and numbers drop from there.
The methanol I use is fuel for fuel cells and of very high purity. Fuel is from a major oil company (BP), sold in their stations from the pump and should not vary that much. It is used as the standard fuel in the DTM racing series in Germay. I won't test it. Not worth the trouble and the expense. It is not sold in barrels in a shop.

The timing numbers I run are not that uncommon. The methanol water injection allows for an extra 5 deg of timing. Part of this advance is to compensate for the slower burn speed.
A similar engine, but with a turbo without meth water, runs 14 deg of advance at 15 PSI of boost without water.

I asked this question myself many times and to other people with substantial knowledge. The engine is surely timed right. If you notice the plug's electrode you could notice that the engine is actually running lots of advance

[Flr Power]

parmas, Did you ever check your timing for drift at high rpm with a timing light?

Also I just realized you said you inject at 60% water/meth fuel ratio. I have only tuned to about 30% ratio so you are in a different league.

I remember when you used to spray very little and now you spray a lot. Good work by the way!

[parmas]

Originally Posted by Flr Power

parmas, Did you ever check your timing for drift at high rpm with a timing light?

I checked it for very few seconds on 4Krpm

Also I just realized you said you inject at 60% water/meth fuel ratio. I have only tuned to about 30% ratio so you are in a different league.

You are right 60% WM50. The injection was gradually increased by trial and error beginning from as small as 10% until 60% which took about 2 years testing and tuning.

I am sure the mixture could handle more WM50 but there are issues I have to overcome first. I have two nozzles 350cc. The pre-turbo is set to inject later than the post turbo by installing a pressure relief valve greater than the post turbo one. Still since I inject very early the engine bogs a bit at low rpm / low boost and high gear.
Reducing injection will make the air temperature fire up accordingly.


I remember when you used to spray very little and now you spray a lot. Good work by the way!

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[rotrex]

At such high water to fuel ratios and a lean mix, the ignition timing numbers look more feasible. I won't use that much mix as otherwise fluid usage on track would become too high. I only run a 1 gallon tank.
Fast Yaris. I liked it.

Are you using a PWM valve to adjust flow over rpm/boost?
I control flow via a aquamist HSV and a separate map in the ECU.

[djfourmoney]

I am going to bump this thread because I am running pre-turbo but not with an Aquamist system.

I choose AEM because 99% of the time WMI will be used is WOT and I'm not interesting in pulling base fuel and replace it with methanol via the water injection system.

I also choose this configuration because I want to get more out of the stock turbocharger.

Starting with the smallest included nozzle (250cc/min), I wasn't sure if it was working like it should. Turns out it did work but eventually some air got caught in the system and it stopped pumping water. I had to undo lines on both sides of the pump to get it primed again and the water flowing.

Logged a short 4th gear pull and sent it to my tuner. Apparently there was enough of a change that he modified my tune. I had changed the nozzle to the middle one included in the AEM system (500 cc/min).

Right now I have inlet temps 6 degrees over ambient though that log was taken well into the evening as ambient started to drop from a mid day high of around 97 (F).

This is only the beginning of what's the come.