Nissan Skyline
Nissan Skyline

R33 GTS25-T
R34 GT-T
R34 Z-Tune

Tuning Guides
R33 GTS25-T
R34 GT-T


Project GTS25-T

Tech Resources
Airflow meters


Project GTS25T





Home > Project R33 GTS25-T Part 1

Project Nissan Skyline GTS25T

Current Specs

This is my own Nissan Skyline that I have owned since 2003. Im the first Australian owner the car was relatively stock engine and suspension wise the only modification was a blitz blow off valve (wow). It did have the same Type M factory kit, and 17Ē wheels you see on it today. The only thing I didnít like about it was the rear wing Im not sure what type it is but it has grown on me as itís a little different I guess.

The first mod to the car was a cat back HKS super dragger exhaust the dealer though in for nothing not sure what difference this made to the Skyline power wise because I had only driven it once but it sounded great and wasnít to loud.
Nissan Skyline
Nissan Skyline
Nissan Skyline
Nissan Skyline

I was impressed with the cars performance in stock form and knew it had plenty of tuning potential. One problem I did however was the famous flat spot that Nissan Skyline's are famous for and I hadnít even touched the boost yet. It only happened every noun again but it was bloody annoying it was especially noticeable in second gear at 4500rpm the car would pause for a briefly then take off again.

Living in a country town no one really knew much about imports and mechanics looked at as though it was some type of alien. I searched the internet and come across a great forum called Skylines Australia I posted my problem and within about an hour I had several replies. Basically I was told that the standard ECU runs very rich and to try re-gapping the plugs from 1.1 to 0.8 then to install a safc or a power FC if the problem still occurred.

I took the car to a local mechanic for a service, explained the problem and asked him to install some platinum plugs gapped at 0.8. The mechanics took the car for a test drive and said they didn't notice the problem before or after the plugs were installed anyway they said they fixed a cracked boost line and gapped my plugs for me. I took the car for a drive the next day and the problem was still there (bugger) I decided to live with the problem for now.

The next thing I decided to do was turn the boost up I brought a 30 dollar boost gauge and a adjustable air restrictor. I used the standard boost solenoid and installed a switch for high and low boost settings. I installed the adjustable air restrictor, boost gauge and switch, tuning was done on the road, when the switch was off 6psi was achieved, and when on 10psi was achieved or so I thought (more on this latter). When the switch was turned on you could feel the extra boost kick in but the flat spot was sill there and more noticeable now.

I was happy with the Skylines power but just had to get rid of that flat spot so I ordered a SAFC. I wanted this problem fixed once and for all so I got back on the SAU forums asked what workshops in Victoria they recommended. After a few phone calls I decided to use ICE Performance as they were helpful and well priced. I explained the problem and what I had done to try and fix it, they said they had seen it many times and the Apexi SAFC would have a good chance of fixing the problem.

The long drive was made down to Melbourne and I left the boys at ICE to install and tune my SAFC2 and returned an hour or so later. The results where mixed the good news was that the flat spot was fixed Gerald (the tuner) said the car was running extremely rich before the tune and now all was good. The bad news was the boost restrictor I used was not working correctly it would produce the required boost for about a second then go back to standard shortly afterward. I was also told the boost gauge wasnít installed correctly as it wasnt connected to a line with vacuum.

Nissan Skyline
Nissan Skyline
Nissan Skyline
Nissan Skyline

The boys removed this setup and boost was set back to the standard level. They also noted that the engine was very healthy and would produce good power when this problem was fixed. 158rwkw was produced which wasnít to bad considering the modís (Sorry I donít have the dyno sheet to show all). On the road the car was much nicer to drive with no flat spots at all, a little extra power was noticeable but I was told not to expect much until the boost problem was sorted.

First ordered a bleed valve when I got home and decided on one from turbo XS as it does not start to bleed air until the set boost level is seen. The advantage of this is that no extra turbo lag is produced like most other manual boost controllers. I installed the new bleed valve and connected the boost gauge to the correct line. On the road I set the boost level to 10.5psi and boy did the Skyline love it, boost came on hard and held until 5000rpm but slowly tailed of to 9psi by 7000rpmI was happy with the extra power.

About 6 months later I got power hungry again so I did some research on SAU to decide my next mod. After seeing a picture of the stock dump pipe and how restrictive it was I decided this was the next thing to upgrade. I ordered a 3" dump/font pipe and a 3" Casco high flow cat converter. Installing was easy with the help of a mate and a hoist we just had to be careful not to snap any of the rusted bolts. I started the car after installation and noticed a deeper yet quieter note at idol (sounded better). On the road the beefier note was noticeable too especially from 4000rpm onwards. The turbo seemed to spool quicker and extra power was noticed particularly after 5000rpm.

Continue to part 2 >>


Free Web Hosting