Z31 Turbo With N20 (question)

[jc052685]

So after a trip to the local 1320' we decided to toss my n20 kit I had laying around onto my buddies 87 z31 turbo. So we tossed the jets in for a 50 shot and it was a pretty good impovment. So 100 shot should be real fun right? Well, it would have been had the fuel pump been able to keep up lol.

 

So once the new fuel pump goes in this week we plan on jetting it for 100hp. Car is 100% stock minus the pretty much open exhaust. The questions is, do you think the nitrous has enough of a cooling effect to turn the boost up to 9psi or so? I was thinking turn the boost up to 9 or so and pull about 2-3 deg of timming out of it.

 

And for all that are curious the car ran a best of 14.2 (all stock except for the exhaust) 265-50-16 khumo Victoracers on the rear.

[DeleriousZ]

If we're talking dry shot, then no, I'm surprised you didn't melt a piston with the 100 shot. The teeny tiny 260cc injectors are your main limiting factor.

 

It is generally said around the z31 community that 10-12psi is fine with minor mods (exhaust, cone filter mainly, and some form of pressure relief valve, not the stock POV). The VG is pretty stout, but it is limited by the pea shooter injectors Nissan decided to toss in there.

[jc052685]

If we're talking dry shot, then no, I'm surprised you didn't melt a piston with the 100 shot. The teeny tiny 260cc injectors are your main limiting factor.

 

It is generally said around the z31 community that 10-12psi is fine with minor mods (exhaust, cone filter mainly, and some form of pressure relief valve, not the stock POV). The VG is pretty stout, but it is limited by the pea shooter injectors Nissan decided to toss in there.

 

Wet Shot!!

[510six]

N20 on a turbo motor is pretty much like 2+2 = 5 . What happens is the nitrous cools the intake charge about 100* and a large shot will "boost creep" the wastegate 1-2 psi higher.

On a N/A L series 3 liter stroker what was a 120hp shot to the wheels became an over 200 rwh shot on a turbo L30 stroker.

 

A friend with a bone stock 85 Z31et ran a best of 12.6 @111 with a 3" downpipe with open exhaust and a welded R200 with a set of ET Streets, with a 100 rwh wet shot.

[Hitman Z]

I will run 10psi of boost, hi octane gas, retard 4 deg. a good set of sparkplugs with the correct heat range and calibration and a 100 shot of nitrous. But whatever combination you believe is good for you, just make sure everything is working properly. Good luck!!!!!!

[jc052685]

I will run 10psi of boost, hi octane gas, retard 4 deg. a good set of sparkplugs with the correct heat range and calibration and a 100 shot of nitrous. But whatever combination you believe is good for you, just make sure everything is working properly. Good luck!!!!!!

 

Yeah, everyone I know runs 93 or better in their turbo cars. Thats a good idea though, I did not think of the cooler plugs. I will tell him to do that. We are going back next weekend and going to be trying the 50 shot then the 100. If he feels everything is going well we my try the 125 jets although I am sure I will be trying to get him to thry the 150 jets muahahahaha:evil:. For the 100 shot We will probably just pull 2 deg timming. Probably will pull more IF we decide to go for the larger shots. He does have a wideband so at least we will know where he is regarding that so the afrs will be safe.

[Hitman Z]

Yeah, everyone I know runs 93 or better in their turbo cars. Thats a good idea though, I did not think of the cooler plugs. I will tell him to do that. We are going back next weekend and going to be trying the 50 shot then the 100. If he feels everything is going well we my try the 125 jets although I am sure I will be trying to get him to thry the 150 jets muahahahaha:evil:. For the 100 shot We will probably just pull 2 deg timming. Probably will pull more IF we decide to go for the larger shots. He does have a wideband so at least we will know where he is regarding that so the afrs will be safe.

 

 

Well my friend whatever you do to accomplished that goal, I wish you good luck and low ET.

[evildky]

you can run 9psi witout an intercooler or any other means of coolign the charge, IMHO NO2 + turbo = bad things, a bud of mine did the nitrous on a turbo VG, and blew the motor, an intercooler and more boost is a much safer way to make your car faster

[jc052685]

you can run 9psi witout an intercooler or any other means of coolign the charge, IMHO NO2 + turbo = bad things, a bud of mine did the nitrous on a turbo VG, and blew the motor, an intercooler and more boost is a much safer way to make your car faster

 

Maybe you can explain exactly how the N20 took out your friends motor? I suspect the nitrous had nothing to do with it unless it was a tunning / operator problem.

[Beck]

You might need an adjustment on some other part.

 

1987 300zx Turbo

Stock size street tires

Stock exhaust

Automatic Transmission

Stock Motor

Stock Turbo

Stock Boost

Open Differential

Heavier tires and wheels, with adapters

 

ran 14.5

 

after a few passes with a boost controller it ran 14.0

 

I'm not trying to give you a hard time about your numbers. It would just be terrible if you focused all your efforts in the wrong direction.

[jc052685]

I dont follow....

 

So its all stock but you messed with a boost controller....hum

 

Auto tranny known to run faster on the turbo cars.

 

So what are you saying? That my friends car was still faster than yours on nearly identical setups before you messed with the boost? And by .3 sec I might add.

[jc052685]

He is the fastest "stock" z31t I see on there.

 

http://www.dragtimes.com/Nissan-300ZX-Timeslip-18625.html

 

 

 

Another post of some one running 13.5psi, FMIC, and 100oct race fuel....and they were still slower. I think 14.2 with only open exhaust on a hot *ss day is VERY good.

 

http://www.dragtimes.com/Nissan-300ZX-Timeslip-903.html

[Beck]

I dont follow....

 

So its all stock but you messed with a boost controller....hum

 

Auto tranny known to run faster on the turbo cars.

 

So what are you saying? That my friends car was still faster than yours on nearly identical setups before you messed with the boost? And by .3 sec I might add.

It looks like you are wanting an argument. I gave you a list and a time. Then I gave you an additional component and a new time. An open downpipe, bigger tires, and a 50 shot of nitrous should be more than .3 sec worth of improvement.

[jc052685]

It looks like you are wanting an argument. I gave you a list and a time. Then I gave you an additional component and a new time. An open downpipe, bigger tires, and a 50 shot of nitrous should be more than .3 sec worth of improvement.

 

Car was not on a 50 shot at the track. The car wil be going to the track and makeing a pass on a 50 shot then a 100 shot.

 

Not trying to argue, just did not see the point you were trying to make. I was mearly asking you to state why you thought a 14.2 was a poor run/ should have gone faster. Now I know you thought the pass was made on the gas.

[jc052685]

N20 on a turbo motor is pretty much like 2+2 = 5 . What happens is the nitrous cools the intake charge about 100* and a large shot will "boost creep" the wastegate 1-2 psi higher.

On a N/A L series 3 liter stroker what was a 120hp shot to the wheels became an over 200 rwh shot on a turbo L30 stroker.

 

A friend with a bone stock 85 Z31et ran a best of 12.6 @111 with a 3" downpipe with open exhaust and a welded R200 with a set of ET Streets, with a 100 rwh wet shot.

 

I was also curious if you had any datalog or other proof as to the 100* drop in intake temp or is that just a guess?

[evildky]

Maybe you can explain exactly how the N20 took out your friends motor? I suspect the nitrous had nothing to do with it unless it was a tunning / operator problem.

 

because he got greedy, tried to spray his way to a faster et on a non intercooled VG (it was in a first gen RX7 att the time)

 

anyone trying to make power on any turbo motor should first add an intercooler, nitrous can be fun, I've played wiht it and got greedy and blown engines wiht it myself, nitrous can be safe if tuned prperly with appropriate size jets, but you can't just throw a 200 shot on a stock motor with stick managment and expect things to go well

[jc052685]

because he got greedy, tried to spray his way to a faster et on a non intercooled VG (it was in a first gen RX7 att the time)

 

anyone trying to make power on any turbo motor should first add an intercooler, nitrous can be fun, I've played wiht it and got greedy and blown engines wiht it myself, nitrous can be safe if tuned prperly with appropriate size jets, but you can't just throw a 200 shot on a stock motor with stick managment and expect things to go well

 

I think that qualifies as an operator problem, lol.

 

Any way, the z31t is dead now, lol. He has 4 spark plugs come apart on a 50 shot.

 

I posted a video of it in the non tech section for those that are intrested.

[evildky]

I think that qualifies as an operator problem, lol.

 

Any way, the z31t is dead now, lol. He has 4 spark plugs come apart on a 50 shot.

 

I posted a video of it in the non tech section for those that are intrested.

lol, whihc is why a boost controoler and an intercoler are a better mod than NO2 on a turbo engine

[510six]

I was also curious if you had any datalog or other proof as to the 100* drop in intake temp or is that just a guess?

 

Cooling Effects

Cooler intake air is denser and contains more oxygen atoms per cubic foot. So cooler air will allow more fuel to be burned and in turn, make more power. A 10 degree drop in temperature can add 1 to 1.5% power to an engine. Nitrous oxide boils at -129°F and it will begin to boil as soon as it is injected. This can cause an 80° or so drop in manifold air temperature. Now if we are dealing with say a 400 hp engine, we can see a gain of well over 30 hp from the cooling effect alone. This cooling effect also helps the engine deal with detonation.

 

I ran a dual stage wet nitrous system with a 60 rwh single fogger 12" before the TB , then a 150rwh shot on 6 "port" foggers. At the time the EFI was SDS and other than some Datta Q logging software (which is LONG gone) . With no intercooler and a basic Spearco water/alcohol injection setup the intake temps dropped around 80* , the air temp sensor was/is right after the TB and the port injectors with additional nitrous were further upstream and would have made an additional nominal cooling effect.

 

This shows the results when 35% methanol as the total fuel was injected upstream of the TB.

 

[evildky]

an intercooler can also drop 100 degrees, my old laptop sadly died but I had datalogs of an L28ET at 13 psi with no intercooler and intake temps peaking at 220 degrees! with the intercooler and 20 psi I was only peaking at 150 degrees, only 70 degrees leff but 7 psi more boost at peak

 

510six definitely knows his stuff and has the time slips to prove it but meth is more of a track tool, an intercooler is more of a street car thing, it never goes empty wheny ou need it