rustycivic

I was wondering if anyone has used nitrous w/ Jun stage 3 cams? any problems w/ it?? thanks

rustycivic

anybody?

PM-Performance

not a good idea. the high duration/high lift, i forget which one , but will keep the valves open longer and waste more nitrous and not fullly burn it. . . .im sure theres a more technical explanation, but thats the best way i can explain it

laughinxxx

By your thinking the duration(time that valve is open) would waste air as well as nitrous. That just doesn't sound right. Do you have another way to explain it? I mean once the nitrous is in the cylinders it should stay in there, just like the fuel should. If it didn't we would get fuel puddling in the head and you would see some nice pyrotechnics when it backfired.

PM-Performance

i think it was becuase the valves were open too long the nitrous wouldnt comust at a fast enough rate and "wasting " nitrous.
i forget how to ecplain it better though. i read it somewhere and the tech amanger at Primedia/Mcmullen argus which is also a pro racer explained it to me one day

laughinxxx

Ok, so you are saying that with the big *** JUN cams the valves are not closed for a long enough time for all of the fuel to combust?

racerxadam

are you thinking something similar to overlap on a boosted car allowing boost to blow straight through the cylinder and out the exhaust

boostin b16

the problem with running long duration cams it that there it too much overlap between the intake and exhaust lobes on the cam causing a waste of nitrous/boost in either application. this occours because when the intake valve opens allowing the mixture to flow in the combution chamber, exhaust cam it still open allowing it to flow right out. i am for sure this is true in a high boost application but, not so much in a low boost application or a nitrous application. i have seen a lot of people use itr and ctr cams for low(10-14psi) boost applications and make great power, but as boost increases so does the waste of boost. now in a nitrouse application i think the cam selection would be less important. unlike boost nitrouse is not going to exit the combustion chamber as quickly.

laughinxxx

Exactly, so the only thing that I can think of is that all of the extra fuel that goes into the motor doesn't get burned before the exhaust valves open up. This still seems far fetched though.

rustycivic

yeah I've been hearing too many different stories...some peeps say you could run nitrous w/ the jun cams and some say you can't...???

RTE117

high duration= nitrous in one valve and out the other, less duration is gonna help get that n20 completely burned and take full advantage of it.

ping83

i just purchased jun 3's and i have nitrous on my gsr already. i questioned a place in chicago about nitrous and these cams and they say that if you retard the timing, then there wont be a problem. i use nitrous only when i need it, so it slows on the wear and tear on the motor. guys who are oem certified and work on these cars day in and day out dont think it is a bad idea. i am just going to follow what they say and go from there.

rustycivic

ping! are you using the whole Jun valve train? and what size shot are you planning on? dry/wet?

ping83

i am using the jun valve train, along with a 55 shot (ZEX) dry. whats your opinion and anyone elses. thanks, matt

crazyitr

I am going to run 150 shot on my fully built and sleeved bottom end with Jun 3's.
All the race builders think it should run bad ***.
I'll keep you posted.

Smashback

Well, look at all the domestics running giant cams and nitrous. Seems to work for them (worked for me before my Honda days).

If you think about it, nitrous is worlds away from turbo or supercharging. Nitrous is not really forced induction. Instead of physically cramming more air into the cylinders, it supercools the mixture so that more is drawn into the cylinders by the engine doing what it normally does.

Overlap normally causes a little unburnt gas to exit the exhaust valve because of the scavenging effect created by both valves being open at the end of the exhaust stroke. This is to ensure that all burnt gas has been dumped out the exhaust.

I believe that with turbo or supercharging, having more overlap will not allow the turbo/sc to fill the cylinders with as much air as it would with overlap. With nitrous, since you're still filling the cylinders "naturally" i don't think the overlap affects things that much.

That's my hypothesis anyway


[Modified by Hatchblack, 1:39 AM 2/26/2003]

whatVTEC

does this mean nitrous won't go good with my crower404's?
by the way i'm planning on running 100 shot on fully built b18b

Sunrise City Rider

Well, if you check out the Turbo Cams for say the 2jzgte or the 4g63, you will see that tuners like HKS and the like make Long Duration Cams for their race cars...

The theory is this: the longer duration will indeed allow the Intake Charge to exit the exhaust ports and because of the turbo's heat, it will combust, spool the turbo even faster and pull even more of the exhaust gases out of the combustion chamber...When your'e running 30psi, you think your'e gonna miss a little of the intake charge when you have more CFM than you can fit in that Combustion Chamber? I don't think so...Now, Emissions will suffer, EGTs will be up, Turbo Life will be shortened, but, power will be Maximum, Scavenging is high, and everyone is happy...

Same theory that works with N/A motors seems to work with Purpose Built Race Turbo Engines...

I mean HKS 272degree cams are a LongAss Duration Cam...thats tons of overlap...

Now, I'm not saying that Jun3s and a T88 have a place together, but its a theory...Someone should try it...After all, you don't see many Turbo Honda Setups coming from Japan...But, look at all the Skylines, Supras, EVOs, Imprezas and what not that are running these lumpy *** HighLift/LongDuration Cams...

Zee

specie

It'd be nice if you have a dyno of your Jun3 without nitrous and then with nitrous. You can compare the hp difference with the shot you're using to see if any of the nitrous is escaping unused.