I haven't posted in a while and this question came to mind: On 'dry shot' systems is there the presumption that the PCM adjusts (increases) pulse width to overcome the extra O2. If so, isn't this a little unstable? That atomic (O) oxygen will combine with just about anything and I wouldn't want to wait for the PCM to richen it up. I've heard these systems are limited to relatively low volumes of NO2 and perhaps that is why they are safe. (Am I correct in this assumption?)

 

Hmm... without actually using or having anything to do with a nitrous system before, I would say that you would want a switch etc. on a chip that would take into account the higher % of oxygen in the intake charge - and just put it in open loop. I don't know whether the 02 sensor has the range to measure the effects of a nitrous charge, with a PCM that can read 02 in wide band you should be able too, but I doubt it with your conventional PCM's...

By the way - did you get my e-mail a while back?

 

Having played with this, most ECM's will compensate to a point for the extra o2.

The problem I see with it is that the o2 sensor is AFTER the engine, therefore the massive amounts of extra o2 goes through the engine first before anything can happen.

And the logic inside the EEC/Code won't even adjust on the first pulse it sees, it takes two to ensure it's not just "signal noise".

So that's at least two cylinders running incredibly lean before the EEC does anything. That's okay with the standard air/fuel ratios but with nitrious, I've always felt that was a bit "slow" in response.

BTW, most of the import cars respond on the first 02 pulse, assuming there is no signal noise.

 

Thanks guys, I kind of thought it was a bit of a shaky proposition. I heard a couple of guys talking about it, a small shot for a cooling effect in a boosted application. I didn't think it was a good idea then, and don't even more so now.

And no, I don't recall a recent email message. I just checked the address I have in my user CP. I check that mailbox on a regular basis. Did you get a bounce back?

 

Have you looked into a wet kit???

 

When you say "cooling effect" I assume cooling the intake charge.
Nitrous (as far as I am aware) increases combustion temps on gas engines.

But it should reduce the intake charge. Not interested in running water injection?

Oh, and I re-emailed you

 

No. I'm not really interested in one. I'm pretty happy with what I have. It's not that I don't like using NO2, I had a plate kit on my 69 Cougar. I loved it.

And BigF350 - Yes, cooling the intake charge on a boosted application.

Still no mail. There is mail in the inbox but none from you. You are sending it to the address listed here at FTE aren't you?

 

Another option HK for a sudden "shot" of intake charge cooling is to use CO2 instead of nitrious. What you do is make a simple row of perferated tubes in front of your intercooler, then just before you want to slam on the boost, you spray CO2 onto the face of the intercooler.

One of the interesting properties of aluminum (and aluminum intercoolers) is after a long run with boost, the intercooler can be heat-soaked, and I and several friends call them "inter-heaters" because of this. One of our friends tried this with a turbocharged thunderbird and seemingly got good results. As you may (or not) know, the stock thunderbird intercooler is tiny tiny tiny, and gets heatsoaked fairly quickly when you've modified everything around it.

Just a thought. This way you're not forcing yourself to play with the A/F ratio...

 

I have had a little experience with doing something similar to what frederic talked about.

I personally had a waterspray kit on my 5.4l intercooler. I toyed with CO2, but I was to lazy to find a reliable source of CO2 where the car was stationed.
On our Subaru rally cars we used to dump a 5lb bag of ice on the top mounted intercooler before a stage.

However if I recall correctly you are using a Keene Bell, so you won't have an intercooler, and you would need to spray CO2 directly onto the intake manifold, which means a dry shot could be more effective....

Oh, and I think I have another way of e-mailing you

 

From what I've noticed and read, I could see a heat a soaked intercooler being a problem more on a diesel than a gas engine. Heatsoaking, on a gas engine, could be a problem if the cooler wasn't sized and/or installed properly to allow adequate cooling, like you mentioned with the T-bird cooler. The only way to know for sure though is to monitor ACT's. Even then, most, if not all EEC-5 PCM's are programmed to pull timing when the ACT's (and even ECT's) get out of control.
The GEN 2 Lightning owners seem to run well with their factory coolers (stock and modified applications), and others running air to air coolers as well. I run a Powerstroke cooler, and even in the heat of the summer, it has always worked well under various conditions, as per datalogging.

 

When you compress air, it gets hotter. So the longer you're compressing air, and the compression you apply, the hotter the intercooler will get.

And you're right... it's typical for turbo-diesels to have a lot more of both on a constant basis by the nature of the design of the turbo system.

Tiny t-bird intercooler (hopefully the link remains active):


Agreed. My friend's GN after some serious modifications had the same issue as well. He was seeing 300 degree ACT's and the intercooler would retain enough heat whereas it would take a long while to cool back off - even at idle.

On my 75 dodge TT stroker I used two t-bird intercoolers, one per side, and experienced the same thing as my friend... but it was a lowish compression engine and I sized the turbos so that I had boost almost off idle, and throughout the RPM range to about 5k. There pretty much was boost all the time, and I had heat soaking problems pretty much continuously. They had reasonble airflow, but not ideal because of where I had to mount them (sorta under/behind the front skinny bumper).

Being that my current truck (93 F350 crewcab) is a Ford, I have a powerstroke intercooler for the project, and when I replaced the radiator support panel I deliberately bought a diesel one instead of a gas one - now I have the holes and the bracketry for the powerstroke intercooler making it a direct bolt-in.

However I'm doing the same thing - sizing the turbos to provide boost almost off idle, so I'm expecting to have heat soak problems again. But I'll worry about that later. I'll make another coolant to air intercooler again if I have to. It makes for hotter ACT's as an average, but it keeps the top temperature range down and the overall ACT fairly consistant around 200ish.

 

I agree, compressing air causes heat, but we're talking apples and oranges here, or turbos and blowers. The point at which a turbo can spool up is far sooner than a blower, and depending on load conditions, it can/will stay under boost longer. At part throttle, under load, a turbo will make a fair amount of boost, and as you know, it'll stay under boost while under load and moderate throttle. A blower, well, you have to be pretty close to WOT before the boost needle moves. I would say the reason those T-bird coolers didn't work was are along the lines of what you mentioned; didn't have ideal airflow, agressive boost settings and they're too small.

I have been running a Powerstroke intercooler on my Vortech powered 94 Lightning for over a year now and my datalogging shows, with a properly sized and installed intercooler, heat soaking will be very minimal, if there is any at all.

 

The theory is the same, but the outcome is different for the reasons you stated.

And also why I at least prefer turbocharging over supercharging, as a general rule.

However, if your vehicle doesn't have a useful, wide RPM band, you can regear a supercharger for more grunt down low. The problem is then your upper RPM range is limited. Which may, or may not be an issue depending on the vehicle and it's general purpose. A heavy crewcab with a trailer might benefit from such a creation, for example.

Even as a pair my dodge 451 stroker cooked them. I was disappointed actually. I figured "how could I go wrong with two?". But that project was entirely trial and error. My "planning" of the project was whatever was cheap and available, so I had an awful lot of compromises, yet some weird and interesting workarounds for some aspects of the project.

Cool.

 

Not to try to steal the thread, but I've been considering methanol injection for my 03 Lightning. Would that be as good or better, compared to a dry shot of NO2?

 

^I say yes becuase it doesn't threaten the health of your engine.