When building a low-compression motor, what other internal mods would need to be worked out besides cams, cam gears, pistons, rods, valves and retainers, valve springs, and tons of tuning? I'm thinking of building a street-driven nitrous engine. I know I will be sacrificing daily driving HP, but if i need to beat that pesky Stang or Camaro, I just need to hit the arming switch I would be setting nitrous up to engage at full throttle in all gears, and I plan on running at least 90-110 shot. I won't be doing this for a while, but I'm gaining personal knowledge for the future...

 

There's no reason to build a low compression motor for a 100 shot of nitrous. At the very least keep it at 10:1 cr. You can easily run a 100 shot on pump gas with a 10:1 cr. Personally, I'd get the bottom end resleeved and bored out to give you more displacement. Then drop in forged connecting rods and the 10:1 cr forged pistons and you're good to spray. The head work isn't necessary to spray a 100 shot, but it will help both your on the bottle and off the bottle hp and trq #s.

 

Yea, for real. Dont lower the compression, increase it if anything. How often are you going to be spraying, if your like me, it wont be very often, mainly for track use and maybe some street racing. I am going to have howellautomotive.com set me up a kit, the Eclipse 420a guys buy their bottom end kits from them all the time, and are very happy with them. They use Eagle rods, but from what I have heard, they handle more than whay they are rated at, which is 600HP. I want to run at least 11.5:1 pistons if I can, thats what the Toyota Celica uses in it 1.8l, and makes 160whp, just think of what it could do our 2.2l H22.

 

How about i sell you my low compression motor (stock internals) heh

 

My friend blew his stock H22A motor with a 55 shot.. well, he actually blew the #1 piston ring, no biggie.. but he decided to replace the internals.. camshafts, valves, springs, retainers, rods, etc. etc. and even UPPED the compression to 11.5:1 with JG Pistons.. And it'll take 100+ shot of nos now.. it's just the internals that you need to beef up, compression won't really fight against you when it comes to NOS.. Lowering compression is good for turbo/supercharger apps.. but with the right internals, you can almost be bullet proof.

Jay

 

I'm still new to the new information superhighway of Honda-Tech, but I thought high-compression motors were great for N/A only. I assumed that nitrous belonged in the same category as turbo/supercharger for FI. I may be wrong and correct me if I am, but in any case, wouldn't a low compression motor be more ideal for a daily driven nitrous motor? However, after some of your guys responses, it would make some to build the motor for high-compression anyway. But could somebody explain the difference between low compression for a turbo motor and for a nitrous motor? Feed me info

 

Well, using Nitrous categorized your car as N/A still.. The time you're not using it, you're N/A.. If you build your motor up for low-compression, whenever you aren't using HUGE AMOUNTS of NOS.. Your car will be DOG SLOW..

Does that make sense? You don't want a low-compression motor if you're only spraying NOS.. you'll be bastardizing your motor for no real reason.

Going the low compression route is only benificial for Turbo/Supercharger applications.. Not for a daily driven car that uses NOS..


Jay

 

NOS is still NA?? The reason NOS still works well with higher compression pistons is because nitrous lowers the intake temperature by about 60 degree's, which is way better than intercoolers can do. High compression and nitrous should compliment each other nicely, and result in some very impressive gains. Problem could be that you would need to run racing fuel when spraying, or at least add some good octane booster. I am going with some 11.5:1 pistons when I do my rebuild, which should be nice to have when I am not spraying.

 

Nos is not N/A it is a forced induction and there for is not N/A so you tell me how that would be natural.

 

Yea, thats whay I thought. I am not sure on what Diversion meant.

 

I think the intention of his original post was to figure out if premature detonation would be a problem when using NOS and stock or higher compression. This question was answered by Toretto, this will not be a problem because of the decreased temperature. I'm not sure about this..but you may want a new ECU if you're going to drive your car daily, because I think you can change the compression ratio on the fly with some of them...but again im not positive.

 

Thank you Styler and Toretto, you answered my question nicely, but all input was very helpful. I still don't understand what Diversion said about nitrous being N/A though. But to clear up, yes, I know that low-compression is not good for a daily driver N/A car, im not dense. I was asking if lower compression was necessary for huge shots of nitrous or not, since low compression is fairly necessary for turbo/SC cars. But thanks, you guys cleared it up Besides I intend on building a high-compression motor anyways, and use nitrous to boost it up some....there's something about N/A that I like, though turbos do kick.

 

Ugggghhh, you guys aren't understanding what i'm trying to say.

First of all, Nitrous is <U>NOT</U> FORCED INDUCTION.

Secondly, when you are <U>NOT</U> using Nitrous your car is Naturally Aspirated.

TypeSwarrior wanted to know is lowering compression would aid in allowing a bigger shot of Nitrous. Clearly the answer is yes, but it's not a good idea on a daily driver to lower your compression just for NOS. Unless you really want to have a super slow Prelude until you spray.

All you gotta do is put in some nice strong internals and that will hold bigger shots. I didn't say Nitrous is N/A.. I said using Nitrous on a car still categorizes your car as N/A, because you're not forcing anything through the motor.

If anybody wants to claim that using Nitrous is forced induction, bring it on. This oughta be good.

Jay


[Modified by Diversion, 10:30 PM 2/2/2002]


[Modified by Diversion, 10:31 PM 2/2/2002]

 

FYI: Most ppl who turbo their engines lower their compression when doing so to decrease the chance of premature detonation.

 

Wtf??

Why are you talking about Turbo when we're talking about NOS?

Yes, I know people lower compression for turbo apps, but people don't normally lower compression for NOS.

Jay

 

You are spraying the nitrous into the engine, which is forcing it in there, just not by compressing air. Its a differant kind of FI, and FI might not even be the correct term for nitrous, but if you run nitrous, you would be in the FI class.

 

Ok guys, how much PSI of airflow is being forced into when shooting a 100shot of NOS? You can't answer that because you're not forcing any air into the motor. I **strongly** suggest you guys to read some type of NOS site that can provide you with a good explaination on how NOS works.


You are NOT forcing air, or anything else into the motor when using NOS! PERIOD.

You could probably be "classed" with the Turbo/Superchargers users, but Nitrous is NOT Forced Induction.

Try again.


Go read the "Nitrous = Forced Induction" thread.

Thread:
https://honda-tech.com/zerothread?id=123366

Jay



[Modified by Diversion, 12:23 AM 2/4/2002]

 

You could argue that the 1200 psi of pressure that is spraying the nitrous into the intake charge is "forcing" oxygen atoms into the cylinders, but this is such a nit-picky topic that it doesn't deserve anymore bandwidth.
**Laughin opens the door and walks out, hoping that everyone else will follow**

 

Sure, the bottle that holds the nitrous can generate that much PSI from the nozzle, but that 1200 PSI changes to the same pressure of the intake manifold before it even enters the motor. So you're still not forcing any air through the motor.

I'm done with this topic, walks out the door with Laughin.

Jay

 

OK.....back to the original topic I understand fully now what everyone's viewpoint is. So here's a new question to keep this topic professional and not opinionated: DIVERSION, you said that people don't NORMALLY build a low-compression motor for nitrous. So what if, theoretically speaking, I were to run nitrous everyday in my car (with low-compression), leaving the armed switch on (the setup would be to have the nitrous kicking in at WOT in any gear)? Wouldn't this basically be the same as having consant boost from a turbo/SC, assuming from your point of view that nitrous is not FI? Would it be as efficient and as safe as a turbo setup with 10psi daily? Why or why not? People build motors for turbo, SC, n/a, so wouldn't this be basically built for nitrous, but safely? Anyone can answer these questions, it's just some things to think about

 

People do build motors for turbos and superchargers, yes.. and yes, the competition drag race imports/domestics do build their motors for NUTSO amounts of NOS, but nobody in a daily driven car will never lower their compression for NOS. Read on....


To answer your question, if you were able to run NOS all the time, then yes, having a low compression motor would be beneficial in order to keep your motor from blowing up, but even if this were possible, it couldn't take NOS all day long.. that's just too much on a motor.

But think of this, say you have a 100 shot of NOS.. You got a H22A, stronger internals, 10:1 compression. Figuratively speaking, let's pretend we're laying down an extra 100 horsepower with the 100 shot.

Now we have a another H22A with stronger internals, and lowered compression down to 8.5:1. We spray that same 100 shot of NOS on this motor, it lays down 60 to 70 hp extra.

You would have to spray a larger shot to equal the power of the 100shot on the 10:1 compression motor. Therefore, spending MORE money on re-fills because you're now needing a 150 shot to equal what a 100 shot does on the stock compression.

You can keep your stock compression, beef up the internals, and be able to spray huge shots without fear of hurting the motor.

It'll be just as safe as lowering compression, without needing to spray larger shots (wasting money).

Don't throw your money away, i'm just trying to look out for you guys, i'm not trying to argue that lowering compression is better for NOS, cause all in all, it's not ever going to be worth it.

Jay




[Modified by Diversion, 1:29 AM 2/4/2002]

 

Well Diversion, I'm sorry if I sounded like I was going to do this to my car. I have no intention. I was just gaining perosnal knowledge for myself just to have. I like to learn about stuff as I go so then I know what I want to do later--keep my options open. Yeah I already knew how many refills that would take, that wasn't really in debate though, but I appreicate you lookin out, bro. Thanks. Now for another question..Couldn't you just retard the timing (drastically) with a computer to slow (lower?) compression on a HIGH-compression motor? Won't the car's computer think the car is running a less compression than before? I'm not really sure how timing works, so maybe you could inform me about timing and nitrous with a high-compression motor?

 

Retarding the timing won't trick the computer into thinking any differently of compression. In fact, the ECU doesn't know what the motor's compression is at anyways. Changing the timing is just actually changing the power band of your motor..

First I need to know if you're talking about ignition timing, or cam timing?

Jay