5 GT Turbo 5 GT Turbo tuning advice

[Ash4ord]

Hello everyone

I am looking to purchase a phase 2, 5 GT turbo, As far as i am aware the engine is stock other than, S/S Carb Lobster,uprated Alloy Intercooler and air filter with a manual boost controller. I don't want crazy power i just want something relatively quick and reliable.

I was looking at cgbmotorsport's website just out of interest at their turbos where they state the following.

Turbo Technics Stage 2 T2/T25 Turbo


" We find many people purchase the biggest they can afford, rather than buying a turbo which suits there driving style."

63 exhaust housing for upto 200 BHP - full boost at 3500rpm - good 30-100+ mph
.47 exhaust housing for upto 185 BHP - full boost at 3000rpm - good 20-80 mph
.35 exhaust housing for upto 170 BHP - full boost at 2500rpm - good 0-60 mph

The above breakdown i found very insightful, 70+ Mph is of no interest to me what so ever as my younger days's of speeding are long gone. Im also not one to race off the lights or from a stand still i would say just a nice feeling of boost and pushed back into your seat action from 20-60 would keep me happy.

What would recommend a good spec to achieve this while keeping the car as reliable as possible?

Kind Regards

Ash.

 

[Ash4ord]

I would just use a stethoscope to listen for knock - cheap and works.

When drilling the 2nd stage use a hand drill - i just put the drill in a small chuck and twist by hand its only brass. Small bit of grease on the drill bit and drill at an angle and a quick blast with carb cleaner when done. A little swarf may get in but its not the end of the world - whoever said the carb is scrap if swarf gets in is talking shite.

My advice is do not go too big on 2nd stage as its a fixed jet. 1.4mm is the max really.

As for mpg step away from the tuning lol they are not bad off boost but if you are changing the air corrector it will not be fantastic on fuel unless you drive it slowly everywhere.

Mate you sure do have a great way with words that inspires confidence lol

Thank's mate will be giving it a go sometime this week.

 

[Brigsy]

its pretty easy mate just get stuck in

 

[solinakias5gtt]

sorry if interrupt.some specs from my 5 to see if u want.

std block and internals std cam light flow work on head cylinder turbo garrett t25 360 thros
std frp /fmic/63 exhaust from downipe/ 120 main jet /0.9 a/c 100 first stage 1.4 second stage @1.3 bar afr 11.0 until 7.000 rpm at 4th gear only problem is that off boost if i press litlle the gas pedal i see 10 afr until 3.000 rpm where the turbo starts to wake up and there rises to 12.5 until 4.000 rpm where i have full bost and 11 afr

a lot to do more ...

 

[Ash4ord]

sorry if interrupt.some specs from my 5 to see if u want.

std block and internals std cam light flow work on head cylinder turbo garrett t25 360 thros
std frp /fmic/63 exhaust from downipe/ 120 main jet /0.9 a/c 100 first stage 1.4 second stage @1.3 bar afr 11.0 until 7.000 rpm at 4th gear only problem is that off boost if i press litlle the gas pedal i see 10 afr until 3.000 rpm where the turbo starts to wake up and there rises to 12.5 until 4.000 rpm where i have full bost and 11 afr

a lot to do more ...

Thank's for sharing my friend! Nice spec, keep us updated

 

[Ash4ord]

Little update,

Fitted the T25, drilled the second stage to to 1.3 and fitted a 1,0 ac, AFR's high 11's and seem more consistent than when i was running the T2 where it would take a moment for the AFR's to hold a consistent number at W0T which made it a little awkward to read, now its pretty much instant when i floor it its straight to high 11's no problem.

Im running 18 psi, T25, standard cam, alloy replacement oe style inter cooler, Im pretty happy with it, I honestly don't feel any more boost in necessary for a road car. sure it would be nice but its plenty quick and its a real blast to drive now, I'd like to get a nice suspension set up and go for some track day's and just enjoy it now.

Do you think a front mount intercooler is necessary for this boost? and would i benefit much from a larger bore exhaust?

 

[Mark Davis]

Glad it's running well mate. Enjoy ! :ag:

 

[Ash4ord]

Glad it's running well mate. Enjoy ! :ag:

Haha cheer's mate hows your's running? I can now begin to appreciate how yours must be now at 20psi! and the people running 230 + bhp mental!

 

[Mark Davis]

It's ok, still need clutch fitting. Then like you mentioned decent suspension. Should be done early next year.

 

[Brigsy]

Told you the 2nd stage drilling is easy get it on track in the new year

 

[Clarkey]

Hows the turbo get that cam changed to get the most out of it.
I didn't run a front mount on my old set up...just a D/C which I still have for sale

 

[Ash4ord]

Told you the 2nd stage drilling is easy get it on track in the new year

Yeah it was piss easy tbh lol , Drilling out the jet in your carb sounded extremely daunting at first but a great reminder to just get stuck in and give things ago, best way to learn! and i definitely want to get it on the track next year.

Hows the turbo get that cam changed to get the most out of it.
I didn't run a front mount on my old set up...just a D/C which I still have for sale

Turbo is spot on mate thank's, loving it at the moment everything it running spot on. Is there anyway to tell what cam i have? A previous owner recently got in touch with me, he said he has lots of the old history with work done etc that he's going to send to me, hes confirmed it has a paddle clutch, My old turbo wasn't a T2 either it was a T2/T25 or a small T25 according to brigsy, A friend of a friend just got a gt turbo and when i looked at his turbo it looked tiny compared to my old one so there is no way it was a standard T2, im now wondering what cam i even have.

 

[solinakias5gtt]

i managed to see 190hp on wheels with 120 main jet 0.9a/c and 1.4 second stage.at these specs i had afr12.9 @6.400rpm.i change main jet to 125 and iwth same pressure as before ihad 202 hp with 11.9afr.yesterday i tried 130main jet and the car seems more power.now i have 11.4afr.one other thing i noticed was that when i used 0.6 instead of 1.0 in first stage my afr @WOT was high 13/14 but of boost was much better than it is with 1.0

 

[Ash4ord]

i managed to see 190hp on wheels with 120 main jet 0.9a/c and 1.4 second stage.at these specs i had afr12.9 @6.400rpm.i change main jet to 125 and iwth same pressure as before ihad 202 hp with 11.9afr.yesterday i tried 130main jet and the car seems more power.now i have 11.4afr.one other thing i noticed was that when i used 0.6 instead of 1.0 in first stage my afr @WOT was high 13/14 but of boost was much better than it is with 1.0

Very nice! What pressure was the 190 at the wheels?

 

[solinakias5gtt]

@1.7 bar i had 190 hp on wheels but like i told before i was with 120 main jet.i am pretty sure that if i had 125 main jet maybe i would see almost 200.and general i have understand that for the c1j to see maximum power you must have afr at least 11.5 and down.and the funny part is that my fmic and exchast are cheap bullshit crap.in the future i will try 1) good highflow intercooler 2) an exchasuts from 60 diameter that i am now to 65 with a decent final part 3)an aluminuim in the turbo from fiat coupe that is with smaller a/r from the t25 that i have now but with bigger size of wheel (trim) 4)venturi in the carb 27 from to 25 std and i am looking how to fix also "butterfly" from 32 to 34.

 

[Ash4ord]

1.7bar nice awesome results from your set up, your inspiring me to play with a higher pressure now! did the car "feel" a lot faster with 24psi compared to 18psi? like night and day? Have you checked for det? and are you running 1.7bar daily no problems?

 

[solinakias5gtt]

thanks mate 4 your good words.so listen the t25 from what i understand needs A LOT of pressure to see results.i remeber many years ago with my t2 even 0.1 counted to see and feel difftence.the t25 at my opinion above 1.5 bar "pushes" hard.less than that u just go fast nothing more.@ 2 bar the car goes ver very fast.with 3d gear u push the pedal gas and you feel the car gets very light like you drive bike.klm goes up fast u must be ready and fast to change gear.the car i run it only bp 100 octanes and det nothing.i have std ignition and i think the trick is to my headcilinder for no det.i have "break" the angles inside chamber.look up in my photo.and no i dont run 1.7 bar all day.i work 2.0 bar every day

 

[Brigsy]

@1.7 bar i had 190 hp on wheels but like i told before i was with 120 main jet.i am pretty sure that if i had 125 main jet maybe i would see almost 200.and general i have understand that for the c1j to see maximum power you must have afr at least 11.5 and down.and the funny part is that my fmic and exchast are cheap bullshit crap.in the future i will try 1) good highflow intercooler 2) an exchasuts from 60 diameter that i am now to 65 with a decent final part 3)an aluminuim in the turbo from fiat coupe that is with smaller a/r from the t25 that i have now but with bigger size of wheel (trim) 4)venturi in the carb 27 from to 25 std and i am looking how to fix also "butterfly" from 32 to 34.

Some of the cheap intercoolers are OK to be honest mine is an ebay special for a supra and works fine. 27mm venturi wont increase hp stick with the 25mm, you will probably struggle to jet the 27mm correctly for high boost. What cam is in yours 285? You are probably at the point where a fair bit of money needs to be spent to gain more HP.

 

[solinakias5gtt]

to be honest my intercooler is std from some lancia turbo i dont remember and i just made metal caps but the all thing is no good designed.i use std cam there is someone here who can make reprofile my cam to renault sport group a(i dont know if i will do it).whats your opinion Brigsy for t28 aluminim and wheel ?also has anyone tried to "open" the std inlet manifold and the butterfly of the carb?