Re-Tune Required GTSS to 2530

[Liptide]

Re-Tune Required GTSS to 2530

Okay I am having a hard time trying to track down information for the particular circumstance I am in. I purchased a GTR several months ago that had the following applicable aftermarket parts:

1992 R32 GTR

HKS Intake Pipes
HKS Cat Back Exhaust
HKS GT-SS Turbos
HKS FCON V Pro 3.1
HKS EVC Boost Controller
 

My turbos went out about a week ago and I have them currently being replaced right now at a shop that specializes in GTR maintenance and modification. I ended up not realizing what turbo's were on the car when I purchased it but I assumed they were either GTSS's or 2530s based on the response time and amount of boost they were able to handle. I ended up ordering a pair of 2530's for replacement.

Now that I know the car had GTSS's in it before and I am switching to 2530's, do I need to get the ECU re-tuned? If so, what specific metric of the new turbo's would drive the need for a re-tune? My understanding is that these turbo's are very similar in response and power output and due to the limited availability of 4-wheel dynos and tuners who can work with HKS FCON products it is going to be close to another 2-3k to get the thing re-tuned and I am just looking to make sure it is necessary.

Edited February 12, 2017 by Liptide
Provide more info on car

[KiwiRS4T]

Are you still in Japan? Would have thought there were plenty of HKS tuners there and why would a tune cost more than $1K?. Why don't you send the 2530s back and get some more GTSSs?

[Liptide]

They were purchased as refurbished units from a reputable dude in Tokyo off yahoo auctions. They don't do refunds in japan for that type of thing. The lack of availability and cost associated is primarily to do with language barrier issues, transportation costs associated with moving the car after its in a 2wd configuration, as well as tolls associated when going long distances in Japan. 

[KiwiRS4T]

R32 you can just pull the AWD fuse to put it into 2wd. New turbos will probably move a little less air at low revs and a bit more at high if you up the boost  so if you leave the boost alone you should be OK. If you have (or get) an AFR meter you could reassure yourself that fuelling is OK but if you are running AFMs you should be near enough.

[Liptide]

Okay gotcha thanks for the help. Will doing the dyno tuning with the fuze pulled damage the system at all? I was under the impression you needed to pull the front wheel propeller shaft to prevent any long term issues.

The FCON is currently tuned using a MAP sensor. Will that change anything in your assessment? Gameplan is to run the same amount of boost/maybe a little less. Used to run 1.4 Bar and ill probably tune it back to 1.2 or 1.3

[KiwiRS4T]

Pulling the fuse is fine on R32 not for R33 as the Attessa is different.

MAP sensor should be able to adjust for airflow. If the shop installing your turbos has an afr meter it shouldn't cost much just to see that afrs are within safe parameters

When and if you get a tune new turbos should make more power than the old ones.

[Dose Pipe Sutututu]

MAP sensors won't adjust for air flow, an AFM or MAF will though.

Throw it on the dyno, check AFR, check where peak torque is, pull timing and it makes more power then continue to do so. Pull timing and it's losing power then add more however watch out for knock and also EGTs.

[GT-R David]

Always remove the front drive shaft.
Sure there is no preload on the R32 transfer case clutch package, but the clutch discs will still be on contact. This may not be a problem when driving on the road and the front wheels have the same speed as the rear wheels. But it will be on the dyno, the friction will produce a large amount of heat.

And also, 2530 are a lot bigger than GTSS. They will be on boost 1000rpm later.

[Liptide]

Copy thanks for the replies.