Nitrous Oxide for cooling???

T-bird4vr

Registered User
Anyone ran though the thermodynamics of a low hp shot to stop detonation or knock(<--not sure what term is correct)?

Maybe a 10hp shot will let us run another 5psi of boost. Sounds like a win win situation. Surely a progam could made to kick it on once the boost pressure hits a certain level. Or even better vary the shot with the boost.

Just a thought. I don't even know how long a 5 or 10hp shot would last on a 10lb. bottle.

Lets hear some thoughts.
-Julian
 
If you have problems with detonation you need to fix the problem that is causing it.
Giggle gas is not the answer.
 
I've been puzzled in my recent readings from MM&FF. In the issue containg the 03 cobra slugfest between Pete Minsky and Jim D'Amore, I noticed that both were running nitrous, and that both appeared to have it injecting before the blower. Correct me if I'm wrong, but that's what the pics look like. Now, I had suggested this before, using n2o to cool the blower as well as the inlet charge, and heard a lot of bad things refering mainly to damaging the blower itself. So what's up with this? Can't quite figure this out.
 
When drag racing at a national level,ALL parts
are disposable.They just need to last one or two
races.
I don't know if this has any thing to do with jet
placement ? though.

randy
 
It is fine to inject a small amout of NO2 only before the blower. You just can't install a wet system before the blower. Actually using nitrous to cool the charge is a common thing, a lor of people have been known to use nitrous to cool from the outside too. Like spraying the IC with it, kind of a waste to me. But back to the topic at hand. What the nitrous will do is cool the charge and require more fuel which both will reduce detonation. You can put the nitrous on a Hobbs switch(I think that's what it is called), basically pressure switch, and once it get's above say 10 lbs it kicks in. Would be a real nice setup. I will agree with Mike though, don't do this to fix a problem, have engine running well then crank up the boost until you get detonation to find point where you should start injecting nitrous. I have found I get it around 15 lbs with my setup, that's when I start shooting alcohol in. Oh and as fars as how long it would last. I have heard a 10 lb bottle will be good for 10 passes or so with 100 hp shot, that means you could run for about 8 minutes with a 25hp shot. I mention a 25 hp shot because I would tend to go with that.
 
If there was someone around close to tune the car I would seriously look into this. St. Louis seems a bit far, and it would probably get a little tricky making it streetable.
Wish I had some thermo tables of n2o. <--edit, I think I do on campus!
-Julian
 
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Probably wouldn't take much. Have system only come on at WOT and just have a chip designed to add 25hp worth of extra fuel at WOT, otherwise run based on MAF numbers. Or you can go trick and have a seperate fuel pump and wet/dry system to regulate fuel that way, but then you're looking at money. It would be fully adjustable from calm to insane which would be cool.
 
If your running lean and getting detonation, the nitrous will only make it worse. Yes it cools the intake charge, but not that much.

With a 100 HP shot of nitrous and a 75 HP shot of fuel injecting into the lower IC tube about 18" before the ACT sensor...we measured intake temps of 90 degrees with the nitrous and 120 degrees without it. I expected it to be a little colder than that.

Spraying it before the supercharger and intercooler would almost certianly remove any cooling benifit of the nitrous. Then again I've never tried it, so I can't be certian.

David
 
You could even run the fuel through a cool can to cool it down even more, if running seperate pump and line. That is a pretty good temp drop though, 30 degrees is 3 % gain just from temp drop. I wouldn't mind getting an extra 10-15 ponies.

David, are those dyno numbers right though? Did you only get 60hp increase with a 100 shot of NOS?
 
Guys, I'm not running lean. That I know of anyway.
Just want more boost.

David, I figured the temp drop would be larger than that. A 25shot might not have much of an effect. Was this after a FMIC or stock?
 
I would worry more about increasing the volume of air moving through the engine than boost pressures. Boost pressures are not where its really at.
Boost pressures are more an indication of restrictiveness in your system rather than anything else.;)
 
Aaron,

The day I used the nitrous (couple weeks ago) it was over 90 degrees with high humidity and I was only making around 340 rwhp and 400 rwtq without it. So it makes nearly 100 extra rwhp and rwtq when using the nitrous. As the outside temps get cooler the HP and TQ increase quite a bit. Around 70 degrees it pulls about 365/430. I expect the nitrous numbers to increase in about the same increments.

The dyno numbers in my signature were from pulls made during the winter when outside temps were around 40 degrees. We had a warm spring this year in St. Louis and the coolest it's been at the track was around 75 degrees, and that's when it ran 12.3.

Chris Wise and I are planning to go to the track this Saturday. I've got a rollbar ready to install, but it's not going in until I know the car is worthy.

David

PS: Yes Julian, the FMIC was in the car...the only changes since then is a Griffin aluminum radiator.
 
Ok, now how the he!! are you keeping the intake temps down to 120? Are you making that much power with low boost? I would guess you would be around 10 lbs with that low of a number.
 
Well, if nothing else it will be interesting to see how well you run David. I would be going to the shootout if I was going to the Czech Republic.
Good luck,
-Julian
 
nitrous before the blower

I was told by one of the local dyno guys who has done a few 03 cobras that I should just inject the nitrous before the MAFS. He said that the cooling effect of the nitrous makes the MAFS adjust the air/fuel mixture to account for the nitrous and it would cool the blower. I've seen him carry a 10 lb. bottle over to an 03 Cobra while it was on the dyno and crack open the bottle into the air cleaner and it responded with over 70 more HP to the wheels and the air/fuel mixture remained safe. I think that injecting it with fuel after the intercooler is a better way to go but he thinks otherwise.
Another thing to think about is that the cobra would have to put the nitrous in before the blower because of the way it is configured. Their intercooler is incorporated into the lower intake manifold.
 
Never mind David, I just saw pic of your engine. The big tubes and front IC probably help a huge amount with intake charge temps.
 
Aaron Pedroza said:
Never mind David, I just saw pic of your engine. The big tubes and front IC probably help a huge amount with intake charge temps.

I thought those numbers sounded really low for the intake temps. 120 after the ic when it is 90 outside sounds pretty efficient.
 
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