234 replies to this topic

[VIN18M]

May as well forge it and run some decent boost...

[svanh1993]

Yeah forged rods should be enough I recon surely shouldn't have to forge the pistons as the rings and gudgeon pin are weaker than the piston ?

[evo-gsr]

Why do half a job?

[svanh1993]

Because it's only a cheap toy haha ? Not a race car I'm not looking at running high boost basically I'll be on full boost by 4000rpm efficiency range for my turbo is 18psi and a minimum of 5 psi is to be run from it 10 or 12 psi will be enough for abit of fun here and there at least it's not always in boost so doesn't chew a huge deal of extra fuel

[VIN18M]

Reason I suggested forging it is because with that turbo and that compression I don't think it'll last long running 12psi.

[evo-gsr]

Because it's only a cheap toy haha ? Not a race car I'm not looking at running high boost basically I'll be on full boost by 4000rpm efficiency range for my turbo is 18psi and a minimum of 5 psi is to be run from it 10 or 12 psi will be enough for abit of fun here and there at least it's not always in boost so doesn't chew a huge deal of extra fuel

Lol.

Thats all I got to that response....

[VIN18M]

I think it'll make boost a lot earlier than 4,000rpm, to be honest it'll be difficult to keep it off boost. Which means your fuel consumption will be pretty high.
Problem being that you will be pumping so much air into such a high compression engine, it's bound to blow head gaskets and/or worse.
Honestly you're in a situation where you're probably better off running wastegate pressure (7psi), but then you've got a turbo that really is made to come alive at 12psi and an engine that can't take that much boost.
Two options:
1) Run less boost preferably through a smaller turbo
2) Build the motor and take advantage of the turbo you have.

Speaking from experience, it's worthwhile taking people's advice on here. I had my heart set on running big cams and gave them a shot even though people on here told me they weren't suitable. Ended up having to swap them out and get my car retuned, more stuffing around, more time and more money.
I learned for myself but in hindsight I should have just taken the advice on board.

[leadfoot]

Its a fatter ar turbo than a td05 and i have no issue keeping the 05 off boost itll definatly come on later than an 05

[svanh1993]

Forged rods should be fine tho for 12 psi right or do I really have to spend almost 1000 just on the pistons for a few more psi I kinda like the neck snapping power that my mates vl has running a highflowed gt3582 it's only on 18 psi and it's awesome chews like no fuel running a rb30 bottom end and 26 heads his boost comes on at 3500 but hits so hard

[Ian91]

http://www.spoolimpo...-and-cp-pistons

[svanh1993]

How Much boost can I push with 8.9.5 cp pistons and forged rods ? On this gt28 ofcoarse trying to stick away from td05 lol or anything smaller really looking for something hard hitting like the gt35 on my mates rig

[jack be nimble]

Is this a na? With na pistons? You are going to be on thin ice with those pistons. Even if you run a fat head gasket to lower comp ratio.
maybe compare weight of na and turbo pistons to get idea of how much more meat is in the turbo jobs. Dont let it knock, rig up a siren and a ball clamp- so it hurts too much to keep on it when it knocks.

but big cr and boost...dying for e85. Lets go...

[leadfoot]

The peoblemnis finding forged rids that dont use a floating pin. The stock units are a captive pin. There are piston and rod combos out there preety sure spools is sub 1500 for both. Or you could experiment with 3sgte or even honda b18 stuff note to use these you must match pis5on and rod

[svanh1993]

Yeah looked at the b18 specks bore and stroke are the same in guessing valves have a difference and the pin sits lower I think

[leadfoot]

those are all things you'd have to reasearch the piston pin height is different. this is why you would need to to use b18 rods to match the b18 pistons to maintaing the correct deck height clearence.

 

i got as far as check bore deck height stroke big-end sizes all match up with the exception of pin height and rod length which when used in combo ofset eachother to match the same as the 4g93. your biggest issue would be valve relief size and clearance and selecting a suitable CR piston ie dish flat or dome for desired compression ratio with the 4g93 head. only way to do this would be to CC the combustion chamber and work out the CR by combining that and the dish/dome of the piston and staking the ratio of how many times that volume divides the swept volume.

ie 50cc combustion chambe is 1/10 of a 500cc swept volume so cr on that would be 10:1

[jack be nimble]

The wiseco catalogue has pin heights included.

[CLuTZ]

This is a good thread! Props to you svanh1993 for asking to do something different.

There's been an upgrade path for the older 4GT cars that has been followed by many over the years. There's a reason why people stick to it. Because it works. A TD05 Big 16g on a 4G93T with usual supporting mods like fuel, intake, exhaust, cooler piping, clutch etc is enough for you to do 12's any day of the week.

 

Don't forget that banging a 'big' turbo on will NOT make your car go faster. Especially if you will be running low PSI and out of it's effiency range. A well set-up and efficent car that is tuned right will not only be heaps more fun to drive, but a hell of a lot quicker all throughout the rev range. 

Speaking from experience (a lot of others will agree with me here too) you should plan your mod path over and over to make sure you

A. Get the most from it
B. Save yourself shitloads of time and cash by buying the right parts
C. Do it once and do it properly.

Failing that- sell up and buy a car that someone else has already spent their cash on and enjoy that then carry on from there.

 

 

dre

Edited by CLuTZ, 13 May 2015 - 03:19 PM.

[svanh1993]

Yeah I'm having a big think about it atm funding is down low abit hence why I only really looked at doing forged spool rods thinking that the rods are the weakest link and to minimise that I have heard of people running 20psi without forged pistons easy just by doing the rods and almost two years down the track his cars still going strong as that's on a precision turbo simular to a gt30 garret range he's making over 400hp atw only things he did was injectors for head room +1mm stainless valves with a 5 degree 3 point back cut fuel pump aem 390lph and a wideband this was all tuned on an apexi ecu by him self street tune and he put it on the dyno to fix up a few other tiny things he said no matter how hard the piston is they all have 3mm compression rings forged or not so if it wants to go the first thing it will do is spit a ring

[VIN18M]

You have to also think about how "streetable" a gt30 is going to be on a 1.8L.
As Dre said, a well set up car will be quicker, don't pay too much attention to final dyno figures as 400hp from 5,000rpm only gives you about 1,500rpm worth of decent powerband (for arguments sake). And on a FWD that'll probably mean lag, lag, lag, wheelspin, change gears, lag.. etc

[svanh1993]

Well he's on full 20psi on 3800 it felt great it's only a 2 liter so not a huge big difference I recon 200 cc isn't going to compensate for the turbo simular to a td0620g so in comparison I think it should be fine hopefully yes I know its a different path but what if it works well some one has to try it hey if they can put huge turbos on these in malasia then I'm sure a 28 won't be bad most people come on boost 18-22psi by the time they hit 3500-4000rpm on these turbos So lag won't be much I mostly drive at 2500rpm anyways and 3000 in the highway top gear