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5 GT Turbo 5 GT Turbo tuning advice

Ash4ord

Member
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 mp
h

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.
 
Well hopefully i've just scored this carb from the "other" Facebook group, just waiting for the seller to get back to me.

Ill be getting a carb rebuild kit. Any tips for cleaning all the muck off the carb when i get it?

933307754204_n.webp
 
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Thanks andy,

The seller has just informed me it has an extra barb for a direct fuel feed to the bowl. I don't want to run any other fuel feeds i want to just be able to remove my standard carb swap it for this one, Can this extra barb be left unused?
 
Don't have a different carb top, Looks like i might have to give this one a miss, Really don't want to mess with my current carb as the car runs perfectly and i want to keep it to revert back to standard if i need to. The hunt for another carb continues......
 
Don't have a different carb top, Looks like i might have to give this one a miss, Really don't want to mess with my current carb as the car runs perfectly and i want to keep it to revert back to standard if i need to. The hunt for another carb continues......
Don't be put off by my comments. Changing the top is simple. I have a few carb spares here and I'm sure a carb top is amongst them. You are welcome to it if you need one
 
Don't be put off by my comments. Changing the top is simple. I have a few carb spares here and I'm sure a carb top is amongst them. You are welcome to it if you need one

If you have a spare carb top that would be brilliant and very much appreciated! how much would you like for it mate?, If your sure about it then i will message the seller of the other carb and confirm that ill take it.
 
Yeah don't bother with so called grp A carbs. Just clean and refurbish your own and jet it correctly.
If you don't want to do it yourself I'm sure there are a few group members to help out.

Other than turbo and more boost, do you plan to make any other changes ? Exhaust, down pipe, intercooler etc?
 
Is there any members in the midlands who wouldn't mind giving me a hand and showing me how to jet the carb correctly? I think i could do it my self but as i've never done it before i wanted to use a spare carb just to be on the safe side.

As for other changes, I have an uprated intercooler and radiator, I am not 100% sure if my exhaust is standard the down pipe appears to be, The back box doesn't appear to be. Heres a pic of the underside, does this look like the standard sized exhaust?

jhgjj.webp

Also does my fuel pump look standard?
uytu.webp
 
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If/when you need it just pm me your address, I will dig one out and send it to you
Thank you mate that's very much appreciated, i will let you know if i need it ( and also if i don't ie won't just forget you offered and leave you wondering ), I want to make sure this other carb doesn't have any other unusual modifications first.
 
Hard to tell from that picture but the back box certainly looks shiny and new.

There are a few people on various GTT Facebook pages that can refurb and drill your carb for specifications of your choice but I'm not sure which ones if at all are members on here. If you wanted to do it yourself there is a guide on one of the other GTT forums that's worth a read. Not sure if TR have one on here. Of course doing it yourself will be cheaper, I haven't done my own yet as didn't have the confidence at the time.

Sounds like you only need to drill the 2nd stage out slightly so shouldn't be too hard. You just need some micro drill bits. I haven't read the carb rebuild guide that Andy linked you too but i'm sure it points out which jet is the 2nd stage.
 
Its the drilling that is putting me off, especially the 2nd stage as that can't be reverted back to standard, what if i drill too far or the drill isn't perfectly straight etc.

I have read that changing the main jet and a/c jet can fuel safely but it will run slightly rich and fuel consumption is increased. Id feel much more confident doing this as i know i could just put the old jets back in. Do you know much fuel consumption is effected compared to drilling the 2nd stage? Is it a big difference?
 
I'm not sure on fuel consumption, mine isn't a daily so I just whack fuel in when needed. It's pretty juicy when driving it hard.

Having not done it I can't comment but as long as you have a steady hand it shouldn't be too much bother. Someone like @Brigsy will most likely know. I've never heard that you cannot change 2nd stage back ? I thought people soldered and then re-drilled? But I could be wrong.
 
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