High RPM Hesitation/Fuel Cut and Glowing exhaust manifold!!!!!

[pmurr181]

oh okay. yeah i don't know that much but i am learning.
With Nistune can i change the ECU maps?

[pmurr181]

Sorry if i sound like a noob at this. So i have to contact someone with nistune software and put the car on a dyno and retune the ECU right? I am located in calgary... do you know anyone in these area that i could get help with this?

[Skym]

Yes, can change maps, tables, etc once Nistune is installed inside stock ECU. With Nistune installed inside stock ECU, just plug laptop up via a consult cable to consult port under dash on drivers side of car and make changes to maps in tuning software and save changes permantly.

Alot of new cars are tuned this way (R35GTR, etc). It's called reflashing a ECU. But with Nistune, can change part of map on laptop and engine responds straight away to changes. Most modern car ECU's require making changes on laptop, sending maps to ECU and then test to see the result's of changes.

Only one place that tunes Nistune in Calgary that I know of -

Autodream JDM and Drift technology
159 5120 47street NE
Calgary, Alberta
Contact Nguyen on 403-248-1566
Info [at] autodream.ca

[pmurr181]

I was just reading a forum on here that said something about the r32 MAFs being incapable of measuring air flow after a certain amount of air, causing a fuel cut or safety mode thing. If i get the Nistune will i have to upgrade the MAF to eliminate this problem or when i re-flash the ECU it will be fine?

thanks again for all the help, appreciate it.

[pmurr181]

oh and do i have to get someone to install the Nistune or is it something a DIY-er can manage and then take it to auto dream for tuning? What's the going rate for this product as well?

[Skym]

MAF (Mass Air Flow) usually maxes out when upping boost level with stock turbo or fitting bigger turbo which sucks in more air through MAF which sits infront of turbo.

R32 RB20DET MAF is rated to roughly 300hp. Z32 MAF off a 300ZX is rated to roughly 480hp and is a bolt on upgrade (some rewiring, Z32 plug is required) when upgrading turbo (requires ECU retune, bigger injectors, bigger fuelpump to match bigger turbo).

I think your cars problem is AFC adjust's the signal from MAF, so it reaches max load limit settings on stock ECU and fuelcut engages to stop engine from blowing up (similar to maxing out MAF). You can raise the load limit setting on stock ECU once you have Nistune installed, but I would fix the cause of the problem first (AFC).

Best to get Nistune dealer to install Nistune parts. You don't need to retune straight away, as ECU should be using the same maps it is now.

[pmurr181]

So when i take it to auto dream should i ask them to take out the AFC or tune it appropriately to the right settings? Would that AFC being so old, be a hunk of junk? would i have damaged the O2 sensors running so lean? or even the exhaust manifold itself? And would the timing be affected as well?

[pmurr181]

Oh and before i go for a retune would it be smart to replace the stock inter-cooler with a larger one?

[Skym]

Remove AFC. It only adjusts the signal from MAF to ECU and probably will cause problems when retuning ECU.

Running rich clogs o2 sensor or doing alot short trips clogs o2 sensor. Or I think running C16 fuel damages o2 sensor. It's best to replace o2 sensor when you buy the car, as it's usually stuffed and needs to be replaced. You'll know when o2 sensor is stuffed, as voltage from o2 sensor fluctuates from lean to rich slower and get bad fuel economy.

Also if you haven't already, change TPS (Throttle Position Sensor that's located on side of throttlebody), 02 sensor, sparkplugs, all of the fluids (engine, gearbox, diffhead, powersteering, brakes, etc), oilfilter, fuelfilter, etc. I've learnt changing TPS, 02 sensor should be done as part of routine maintenance (change every 40,000-60,000kms) and change them when you buy a Skyline with unknown service history.

From what I understand running lean can damage rings or headgasket if engine was knocking. Dry and wet compression test engine to see how bad the damage is.

If compression is ok, before ECU tune, change sparkplugs (NGK PFR6A and gap to 0.8mm) if your car has intake, exhaust mods and going to fit intercooler.

Correctly sized aftermarket front mount intercooler is worth it if you want to extract the most hp from ECU tune.

[pmurr181]

I have apexi intake and 3 inch exhaust. the only things i haven't done is the plugs and inter-cooler. everything else mentioned was done. What appropriate inter-cooler for intake and exhaust and small future mods do you recommend?

[pmurr181]

and 02 senors i haven't done but will be done asap

[Skym]

Depends on the cars application (street, racetrack, dragstrip, etc) and turbo to match application. Usually you upgrade turbo, intercooler at same time, as they are matched to work together at a certain boost level. It's alot of maths involved. Most tuners in Japan sell turbo kits with matching intercoolers, so it saves customer having to work out what turbo, intercooler match.

With intercoolers you have cores that are bar n plate (most cheap Chinese made intercoolers are bar n plate) or tube n fin.

Read this link below that explains, shows the difference (flow figures) in flow of bar n plate and tube n fin cores and shows the different internal design's of the cores -

http://www.are.com.au/techtalk/intecoolersMR.htm

Usually most fit a stock R33 GTR intercooler with custom intake piping, as they are good up to around 536awhp on R33GTR.

HDi is another good intercooler (17.2rwkw / 23rwhp gain on RB25DET engine) -

http://www.youtube.com/watch?v=t6FJUmChzgQ

Probably get slightly less but similar hp gain on RB20DET.

Can see the hp gains in midrange, topend with HDI intercooler. That's where factory intercooler becomes a restriction at higher boost levels due to higher pressure drop which drops boost level, hp on dyno plot. Pressure drop at certain psi for HDi intercooler is mentioned on this page -

http://www.hybrid-power.com/products.php?subtypeid=154&subtypename=GTS&PHPSESSID=9c797ef88284f1cba0b92a9c0cf55c41

There's no way factory turbo will last at that boost level in above link, but shows you that HDi intercooler won't become a restriction, even with a slightly bigger rebuilt / highflowed factory RB25 turbo.

Incorrect intercooler for application will heatsoak under hard driving, constant high boost conditions like racetrack use and engine loses hp. But be ok on the street where turbo is not achieving full boost all of the time.

HP gain comes from increase in boost level at intake manifold (leans out rich factory A/F ratio) due to less restrictive intercooler core.

High pressure drop of above 1.0-1.5psi at boost level you want to run = restrictive intercooler core.

Here's a boost plot from dynograph, showing the 1.4psi or so increase in boost level (look at bottom right corner of graph to see the difference in boost level from before and after fitting HDi intercooler) -

http://www.hybrid-power.com/GTSPEC%20INTERCOOLR/boost.jpg

[pmurr181]

wow you know your stuff.
I have never heard of HDI inter-coolers, thanks for the info, i am learning so much so fast. Do you recommend and places to buy HDI products?

I also have an issue with the rack and pinion steering rack, the seals are leaking fluid and i need to replace it for Out of Province i think. Do you know anywhere i can get a new rack online or do i have to order one from Japan, or would it be worth it to just replace the seals....?

thanks again for all the help!!!

[love_boost]

not sure where oyur located but i think import concern is selling one for 80 bucks.
not sure on changing seals though, i would think the rack looks simular to a Z32

[Skym]

I just picked up a few things as I learnt more about car and how it works.

I think there is a dealer for HDi in Canada. Can't remember who though.

If you struggle to find new seals from Nissan, I think a steering rack from PS13 fits R32 GTS. It's mentioned in this article on "Ditch the RB20DET" from a Japanese magazine (Option) -

http://www.jdm-option.com/eng/feature/06_02/r32.html

Also something about relocating tension rod due to more steering angle.