I swapped my 1mm boost jets to 0.8mm last night ;)

 

Jeeeeeeeez it flies now!! What a rush! :eek: :eek: I had gotten used to 12.5psi and this is like having a new, much faster car!!! The boost gauge showed a peak of exactly 15psi.

 

It was 8-10*C outside, no detting in any gear/speed so I'll keep them in and see what its like when the weather warms up :)

 

Cheers to Cos for the idea of cutting the hoses and using 2 jubilee clips to hold onto each end of the jets :cool:

 

:D:D:D

 

Pete

Now all you got to do is learn to park , get that beard trimmed and you'll be there mate :p :D

Originally posted by Baggins

Now all you got to do is learn to park , get that beard trimmed and you'll be there mate :p :D

 

Send me your address so I can post the beard trimmings to you mate, and some treacle to help you stick them on ;)

 

Still grinning...

:D

Pete

 

You are running an upgraded chip aren't you? Sommat like JWT!

Have you done a boost leak test?

 

With 1mm jets I peak at 16-17PSI and settles at 15PSI.

 

Stuart

Yeah I did one on Sunday and no leaks.

 

I've always thought 1mm jets should've given higher then 12.5psi which is why I bought the detector.

 

There's nothing else to suggest a leak.

 

What negative pressure is the car supposes to idle at? Mine sits at just above -19/20psi, which I think is low enough to show air's not leaking in at idle.

At idle, it depends, it changes slighly. Anywhere between 19 and 23/24.

 

Stuart

I'd think 0.8mm was giving you more than 15psi.

I've had loads of Z's using 1mm and getting that!

Just be careful, it's fun but you might be peaking well above 15psi

The gauge is new so I hope its accurate, I'll check it on a known stick boost car if I get the chance.

 

Tho I just think its the fact that different jets produce different booston different cars :confused: - any ideas why???

 

http://www.300zx.co.uk/forums/showthread.php?s=&threadid=24942

Plus surely with stock turbos, injectors and intercoolers I couldn't boost much higher could I?

 

I think they're all stock anyway ;)

Originally posted by pete shrimp

 

Another thing - the car actually feels smoother through the rev range with the higher boost :confused:

 

I've noticed that on mine with an AVC-R. "A" is set to .9 bar and "B" is set to .7, and seems a lot happier mid-range in A. Maybe it's sommat to do with lag/spool-up?

Originally posted by zevans

I've noticed that on mine with an AVC-R. "A" is set to .9 bar and "B" is set to .7, and seems a lot happier mid-range in A. Maybe it's sommat to do with lag/spool-up?

 

Interesting...

 

The only things, I've changed are the boost obviously, and now the wastegates hoses (is that what they are?) are a few inches longer which could affect lag could it not?

Your stock turbos will go over 20psi no problem but they won't be efficient. Still dangerous though!

I had mine running regularly at 18 or 19psi...

 

Boost jets will give different results depending on slight leaks in the system and the fact that the jets might not get a perfect seal in the pipe and allow some air past.

Originally posted by ChrisC

I had mine running regularly at 18 or 19psi...

 

 

And it went bang!:dance:

Originally posted by BigRoy

And it went bang!:dance:

 

Well the bottom end fell apart due to lack of oil by the look of things so I don't think it was anything to do with it really.

 

:slap:

 

The maximum I was running on a daily basis was 17psi.

I run 15psi with 0.8 and 0.6 jets, checked the pressure using Jeff's boost guage, no det that I can hear. Now the clutch is starting to slip when cold and I've only done 2000 miles on the stock clutch!

Originally posted by Homebrew

I run 15psi with 0.8 and 0.6 jets, checked the pressure using Jeff's boost guage, no det that I can hear. Now the clutch is starting to slip when cold and I've only done 2000 miles on the stock clutch!

0.8 and 0.6 , do you mean you are using one of each ??

Originally posted by Baggins

0.8 and 0.6 , do you mean you are using one of each ??

 

Yep, i'm using 0.8mm on the left turbo, and 0.6mm on the right turbo.

Originally posted by Homebrew

Yep, i'm using 0.8mm on the left turbo, and 0.6mm on the right turbo.

Umm I might be wrong here but I am pretty sure that is bad news as the Wastegates will be opening at different times , I am sure some of the other guys will know an awful lot more :(

Originally posted by Baggins

Umm I might be wrong here but I am pretty sure that is bad news as the turbo's will be opening at different times , I am sure some of the other guys will know an awful lot more :(

 

Now you got me worried. I was under the impression that the balance bar made the pressure equal to both sides of the engine so not causing problems. Anyone know if I have a problem using two differant sizes mig tip's?

Originally posted by Homebrew

Now you got me worried. I was under the impression that the balance bar made the pressure equal to both sides of the engine so not causing problems. Anyone know if I have a problem using two differant sizes mig tip's?

I asked a very similar question about a year ago regarding using two different size jets , and in no uncertain terms got told not to do it , I will try and find the post mate :)

The balance bar will just about equalise the pressure, but one turbo's running harder than the other.

I'd imagine the fuel distribution won't be great either as the system is designed for equal flow through both throttle bodies with no real flow through the balance bar.

Also, the pressure won't be dead equal on both sides as at high flows the DP across the balance bar will be higher.

i use 1mm tips and i think my car is over boosting

it just keeps shuting down when turbos cut in

after about 30 miles it seems ok?

 

 

steve

Why run different sized jets? :confused: They've gotta be the same size. When you fit adjustable actuators its very important they are both set up equally using a compressor. The basic effect will be slower spool up. Remember its a x-flow engine so the left turbo boosts the right bank and vice versa. Its very difficult to explain but basically the car will hit target boost on the larger jetted turbo, then slowly reach target boost on the smaller jetted turbo. Despite the wastegate being fully open on the larger jetted turbo, it should still boost past target boost due to being fed by the other turbo. I know what I mean! lol

 

Just change the smaller jet for a 0.8mm one...

 

CheerZ,

 

Andy

Don't run too much boost else you'll blow the welds on your intake manifold. (nee FMIC)

 

I broke it last night; arse!!