Some Suprises In My New Car!

[O_Sotiris]

Hi guys,

I bought an r34 GTT last week with full factory Nismo body kit and am extremely happy with it.

I have never owned a skyline before and when I took some mates for a drive in it they have all said it pulls hard (for what is apparently a stock car).

Anyway, I was keeping an eye on the boost guage and it seemed to be boosting too high - 1 bar!

So we had a look for a boost controller and there was none. What we did find however was that someone had put a small valve in the hose going into the turbo (where you would usually install say a turbotech tee controller).

Here is a picture of what we found:

Another angle:

So it appears that my "stock" car was boosting to around 14psi because of the above instrument!

HOWEVER, the car has been running like a dream. No pinging or weird noises from the engine bay.

So a friend from this forum suggested I take a look at my ecu to see if it's stock. And I found this:

Another angle:

I am pretty sure my car is running the stock turbo as it still has the heat sheild on. I will be taking it off in the next few days just to make sure. There is NO intercooler.

I am now running the car without that valve to be safe and the boost guage shows 1/2 bar which I think is 7lb. There is a MASSIVE difference in power.

My question to you is:

1. Has anyone seen these valves before?;

2. Does anyone know anything about this IMPUL ecu?; and

3. How could my turbo be coping with such high boost if it's stock?

Thanks for your time! Appreciate any feedback.

[bozodos]

dunno bout the valve, but a mate has an impul ECU in his A31, goes farken hard, and no pinging with 98 octane fuel.

it would either be a remap or a resocketed ROM chip inside, I'd suggest not opening it.

[CARSICK]

nice upgrade - negates the speed limiter too (not that you want to exceed 180km/hr)

[O_Sotiris]

dunno bout the valve, but a mate has an impul ECU in his A31, goes farken hard, and no pinging with 98 octane fuel.

it would either be a remap or a resocketed ROM chip inside, I'd suggest not opening it.

Yeah mine was going hard as (it's not now because I removed the valve) - and no pinging or anything!

nice upgrade - negates the speed limiter too (not that you want to exceed 180km/hr)

Hmmmm does that mean I can actually make use of the Nismo 300km/h cluster

[(OO)SKYLINE(OO)]

I haven'e heard of putting in a small valve into the turbo hosing...

But if it is anything like the GTR's, there is a valve that is a removable restricter in a hose to the boost solenoid for a safe factory Boost Increase.

I think stock you should be running about 7 - 8 PSI, once restricter is removed it raises it up to 1 Bar = 14.7 PSI.

From memory IMPUL re-tune / re-chip Nissan OEM ECU's, similar to what MINE'S do in Japan.

So it is your factory ECU but IMPUL have refined it to maximise the Air / Fuel ratio = Car runs smoother = Performs better = Faster car.

[gfunkk]

leave the valve in the hose

the impul ECU will be tuned to run that boost

[O_Sotiris]

I think the way the valve works is sort of like a turbotech without an adjustment? i.e it constantly lets a certain amount of pressure into the turbo.

So when it was in the hose i was running at 1 bar. But now that I have removed it its half of that (closer to stock - 7psi).

I agree it was performing great and running very smoothly on high boost.

Would it be damaging my turbo/engine though?

- I still think its a stock turbo (heat shield still on it - which I will have to remove to confirm); and

- no intercooler + high boost??

[(OO)SKYLINE(OO)]

Your turbo could be stock, rebuilt of aftermarket, not sure till you have a look.

I would just leave everything as it is and put the valve back in, from what you said.

+ Your ECU would have been tuned to that set up with the turbo.

A R34 GT-T side mount intercooler are good for just over 200 kW's.

[O_Sotiris]

O.K. Valve is back in and the car is boosting nicely again.

Did any cars come out with the impul tuned ecu from the dealer? You will notice in the pic that there is a Nissan seal on the left side of the box.

[(OO)SKYLINE(OO)]

O.K. Valve is back in and the car is boosting nicely again.

Did any cars come out with the impul tuned ecu from the dealer? You will notice in the pic that there is a Nissan seal on the left side of the box.

From memory IMPUL re-tune / re-chip Nissan OEM ECU's, similar to what MINE'S do in Japan.

So it is your factory ECU but IMPUL have refined it to maximise the Air / Fuel ratio = Car runs smoother = Performs better = Faster car.

After buying the car, the owner will have to take it to IMPUL to get it tuned.

[jjskyline79]

Yeah seen the valve thing before the end of a bic pen tapered end will do the same thing a few guys back home use to run with them

Thing is i think what they did was earth the stock 2 stage set up first to run factory high boost from get go with the added ecu remap.

Have you still got two stage boost????

[O_Sotiris]

Yeah seen the valve thing before the end of a bic pen tapered end will do the same thing a few guys back home use to run with them

Thing is i think what they did was earth the stock 2 stage set up first to run factory high boost from get go with the added ecu remap.

Have you still got two stage boost????

I don't think so. I'll have another look tonight, but it seems to just boost up gradually. How would I tell if it's 2 stage?

[benro2]

Would you be able to tell us what sort of fuel consumption you're seeing? If possible, in L/100km... and what type of driving you mostly do - like city/highway, drive hard or like a granny, etc.

Also, does it run fine on 95 octane? I wouldn't run my car on that normally but sometimes on a long cruise, say from Melb to Syd, you don't have a choice!

The reason why I ask is because I've seen some people getting woeful fuel economy from these aftermarket ECU's, as they supposedly actually richen the mixture!! I would have thought they'd lean it out a bit but anyways...

My ECU has been partially fried and I'm considering getting an Impul one. This is for a S2 R33 GTS-T auto though.

Edited April 17, 2010 by benro2