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.

 

[DaveL485]

Just went to halfords to pick up my sump socket attachment, came back and tried the bolt in the manifold while hot, it came undone happy days

Thats good, but the car will remember it gave you a pass on that one, and it will come back for revenge at some point lol

 

[Mark Davis]

Yeah GTT's have a knack for getting revenge later on down the line.

 

[Ash4ord]

lol, well i just got done with the oil change, filter was a bit off a piss about, at first i was like how the hell am i going to get this off!I manged to squeeze and oil filter tool onto it and loosen it from the tio then reached in from the wing. Having done it once now i think ill be fine next time tho.

The only thing that really went wrong was spilling a bit of oil down the front of the engine as i began pouring the new oil in and not been able to reach in to wipe it off will this be ok it and won't catch fire? oddly enough my fire extinguisher arrived today i hope that isn't a sign lol

Finally wide band is all wired up can anybody tell me what readings i should be getting? i thought i bookmarked a thread i came across somewhere but i can't seem to find it now.

 

[Mark Davis]

Oil should just burn off but be prepared for a smoke fest for a short time.

AFR's mid 14s on idle, 14/15 cruise, 12 or lower at WOT.

 

[Ash4ord]

Oil should just burn off but be prepared for a smoke fest for a short time.

AFR's mid 14s on idle, 14/15 cruise, 12 or lower at WOT.

Thank you! will go for a test after lunch.

 

[Ash4ord]

Right im getting mid 14's on idle, on cruise im not sure tbh what defines cruise? it seems to fluctuate quite a lot while just driving around it , but under wot im seeing high 11's

Currently running 10psi, i have a manual boost controller or bleed valve fitted as you can see in the pic, i think ill leave it in if it makes adjusting the boost easier not that ill change it once its set up. Does anybody know which way i should turn it to increase the boost and how much roughly to turn it per psi? i literally have no idea like how much one full 360 turn will increase etc. it appears to have two bits that turn, i assume its to lock it in place, which is confusing lol.

 

[Mark Davis]

I think qtr of a turn is a couple of psi but don't quote me on that. When setting mine up I just tested out gently until I had desired boost. I would raise it too much more then if you are getting high 11s, could potentially lean it out if you go too much higher without jetting carb.

Also bleed valves are different, my old one was turn out to increase but the new one I have is turn in to increase boost.

 

[Ash4ord]

Thanks, i guess ill just have a tinker and and use small increments, So basically if im higher than 12 on wot that's running lean and i should back off the boost? I think i was seeing around 11.7/11.8 under wot. so i could sneak a tad more boost hopefully before i have to start playing with the carb.

The car is already pretty nippy i just feel with a little more power it would be perfect, but that said i could end up on that road where its never enough. either way im enjoying playing around with it, its all part of the fun.

 

[Mark Davis]

@Brigsy is the man to tell you all about AFR's and what they should be at WOT but on higher boosted cars like mine I've just been advised to keep it a little richer so I tend to keep mine around mid 11s. I am assuming that if you are running lower boost then you probably have a bit more leeway. Either way find out before you go too crazy, lol.

 

[Ash4ord]

lol i can now see why people can't restrain them selves and end up winding the boost up regardless if they have had the carb jetted or have a wide band fitted and end up braking things, When i was younger i think i would have been one of those people, Thank fully being older and wiser im not finding it too difficult to resist the urge

 

[Mark Davis]

Lol, I started out with the same idea as you. In my case buying a 5 for nostalgic reasons, it didn't take long for it to get out of hand.

 

[Brigsy]

You will need to rejet the carb for more boost to be honest. I would keep it in the high 11's at wot

 

[Ash4ord]

You will need to rejet the carb for more boost to be honest. I would keep it in the high 11's at wot

ok mate ill take your advise on that, im pretty happy with how the car is currently running to be honest, i think ill just enjoy it for a while and keep an eye out on ebay for a cheap carb i to play with.

 

[DaveL485]

Just my 2p's worth, I always think a good point of reference for adjustment on those bleed valves is 1/6th of a turn at a time, ie, match the flat faces of the hex screw up with the body.

 

[Ash4ord]

Do different gears give different readings? the last run i did was on the motorway in 5th, Today ive noticed low 11's and 11.4 in 2nd and 3rd gear, its been wet out side though so can't really get a good run while maintaining traction.

Also anybody got a black bonnet and front bumper, or front bumper in any color? I haven't crashed it yet lol but my front bumper does have a some minor damage and id like to get rid of the bonnet pins. i want to put it back to as close as original as possible cosmetically only thing i want to do it keep it lowered.

 

[Mark Davis]

Be prepared to pay good money for a front bumper.

I wouldn't worry too much about your AFR's, they seem fine.

 

[Ash4ord]

Ive found a fiberglass replica bumper un painted and im pretty sure that's what on mine currently what i am concerned about is do they have the mounting points like the original bumpers?

Are the bumpers easy to remove on these car's?

 

[DeanGT5]

Let me know if you need an afr gauge

 

[Mark Davis]

Yeah bumpers are easy to remove, 4 fixings. One on each side and a couple in the middle.

 

[Brigsy]

Always use 4th gear for checking afr's a long pull up to high rpm. It will be ok though by the sounds of it