What discharge temps are you guys seeing when your alky/h2o systems are on?

I ran my car today and I was seeing discharge temps in the high 160's to low 170's. The temps at the start of the run were in the 120's to 130's. Does this sound about right or is something totally off. I thought that it would drop them even more.

Setup is lt4, vortech s trim. 2.85" pulley with the engine at 5500 rpm, approx 6-7 psi at shift point. About 10gph of flow at 5500. No knock at 5000-5500.

Data was obtained with tts datamaster(ia temp box).

 

Ahhhh, what I would not give for IATs in the 160-170°F range. I am steadily in the 225°F range. I have purposely left the timing down in the 21° range to counteract the high IATs. I previously ran in the 26-29° range.

Sounds like you have some decent IATs.

Aaron

 

wow! do you guys have intercoolers? Thats pretty high for only 6-7 psi. bruce's water air setup rarely gets over 120 deg, even on the hottest of days. and we were running more boost then.

I wonder what my iat's will be on alcohol?

 

I don't have an intercooler. I just have the alky injection. I thought that I would see 20-30* above ambient using the alky, but maybe it's partially because I'm injecting a pretty low amount. The main thing is that I'm not seeing knock anywhere in the upper rpm's.

I guess it's not too bad considering with my pulley setup that I'm actually spinning the s trim pretty good.

Air/h20 is nice if you have a properly setup one. I know guys that run below ambient at the start of a quarter run and about ambient at the big end of the track.

Anyone else?

 

Aahh that explains it then. have you tried larger jets? altering your water/ alky ratio?

 

I haven't yet. I just got the datamaster program running friday so I'm still trying to get things baselined and the car running good.

Right now I'm running about 20-25% methanol and the rest peak -20* WW fluid which is supposedly about 30% alky.

Once the resevior is close to empty I'll probaby mix my own 50/50 h20/meth mix.

I bought a ton of jets, so I'll probably try stepping it up several gallons and then leaning it out until I see some knock. My guess is that I probably need a tad more flow. Maybe a gallon or two.

I plan on running the car without the alky with the btm on for comparison's sake too.

 

That will be interesting data, do share when you have made your comparison. I wonder if you could use cool power model airplane fuel. Say 15-20% nitro, it has 20% castor bean oil and the rest is methanol. I bet ot would be a large hp jump due to the oxygen content of nitro.

 

funny that you mention that! I was already planning to use the hobby fuel(same as what you're talking about) once I get my car setup and the s trim maxed out. Snow performance sells some stuff for $29.99 a bottle which appears to be very similar to hobby fuel. Heck, for $29.99, I can get a gallon of the stuff at the hobby store and I can choose how much nitro, up to 35%. I was going to only toss in about 8 oz per gallon or so and log the results on the dyno. It might be almost like a nitrous kick with the extra oxygen.

Also, the oil won't be a problem will it? It's just lubricant right?


just for reference on my earlier post, it was about 90-95* outside today when I took the measurements. It was a hot one!

 

Rick is right on. At cruising the IAT is 98-103 and at WOT blast it shown 119. We have never see 130 and above. I guess the water to air intercooler is working really good in conjunction with the a/c system on.

Bruce

 

Where is your IAT sensor in relation to your alky injection jets? For example if your jets are located downstream from the IAT sensor then your sensor is still reading the air charge temperature before any cooling effects from your alky system.

 

You need to have your IAT close to a foot downstream to get accurate readings of the cooling effect, and that is nearly impossible on a typical LT1 blower car. I would tune it based on timing and knock.

Doesn't the ECM lean out the mixture as IAT goes up??

 

excellent point.

My setup is dual nozzles(low output) mounted in between the bypass and the iat sensor.

 

Do you have a vortech setup? I'd move your IAT sensor to before the blower. The water/alky mixture is supposed to be bad for the "open" style IAT sensors. It's not really doing you much good there anyway.

 

quiketz,

I would move your IAT further forward of towards the Air filter, it causes the ECM to richen up your mixture. ~it will be like herding cats as you try to dial things in~

In tests that I ran, your "about" right... Mine actually were closer to about 155 at max boost and would simmer back to about 130. Givem my tests were run when it was still in the 80's not 100's like this week

Prior to the alky injection with no intercooler I was hitting in the neigborhood of about 230 at full boost. Running AFR at 11.5

If you are not seeing knock you can advance your timing, what are your O2's reading? If your O2's are still in the 900's you can pull your fuel back, if you are in the 850's you can pull little water back or advance your timing a degree or so at a time until you just start to see knock, then you will know the "boundaries"...

I'm roughly at about 25 * at WOT running about 18 GPH 50/50 running at 880 on the O2's. Which will all change once I get my 8 rib back from Greg

Mo

 

One thing we all have to remember about alky or water injection in general. While we all are wanting the so called "intercooling effect" of the aqueous type of intercooling. Most of the cooling doesn't really take place in the intake manifold itself. Where it does take place is in the combustion chamber. This is where the latent heat characturistics of water cools the chamber temperatures down drastically. Latent heat is defined as the amount of energy (in this case heat) that a liquid absorbs before it changes state from a liquid to a vapor. In the case of water its latent heat value is 2258 kj/kg while gasoline is 348 kj/kg.

As you can see water absorbs considerably more heat energy than gasoline does. So the actual intercooling takes place within the combustion chamber. It is a good idea to place the IAT closer to the air filter or tune the IAT compensation tables out so that there is either no compensation of little. I would prefer to see the sensor just downstream of the filter. Another thing to remember in the cases where alcohol is also used. Alcohol is another fuel source, so that means that when you are tuning, you have to take that into consideration as well. Meaning that if you tune for a 50% mix of water and alcohol, you should maintain that mixture. Because if you were to say just have water in the resorvoir one day, you may risk a lean out.

 

As always... excellent observations TJ

Mo

 

just glancing at one of wot runs, the 02's were 900-950 from 4000 rpm to 5500.

I'm seeing a max of .4 kc in between 4000-5500 but keep in mind, I'm still in the process of dropping the btw. It currently is at 3/4*. Each session I'm dropping it by a little more. Once I start seeing some knock I'll up the alky by a gallon and compare the dyno graphs to see if power falls off much. As long as power doesn't drop off too much then I'm probably okay adding more alky/h20. Once I get a wideband than I'll probably have to lean it out slightly so that I can get things back where they should be with the afr.

Also, the spark advance box starts at 24* at 4000 rpm and then is up to 27* at 5100-5500. Is this normal/typical of a blower car?

On the topic of relocating the sensor, looks like that'll be the next mod to my car.

On another note, one thing that I learned is that my stock tach is way off. Probably about 200-300 rpm toward the higher revs; if not more. It's really interesting to watch the computer and then compare it to the dash.

 

One thing to remember about Datamaster is that it isn't in real time, well sorta it is. Its always a few hundredths of a second behind the PCM. So the tach reading you get in DM may not match that of the dash tach.

 

WOW!! GUYS IM ALL IM RIGHT BEHIND YOU IN ALL THIS TUNING STUFF, I JUST GOT MY LAPTOP LAST WEEK & MY CABLE TODAY, NOW FOR THE PROGRAM FROM DATAMASTER IM CALLING TOMARROW, KEEP THE GOOD INFO COMMING,IM SURE ILL NEED IT! AND POSSIBLE SOME HELP!!

 

another so cal guy. Mo' is from San Bernadino and I'm from Fullerton.

Good luck with the ride. We'll be learning together.