Simple question really, but what would make the GTiR a 2.1 if only changing the piston size?
Sr21det
- Thread starter fubar andy
- Start date
red reading
Active Member
87.5mm is as near as dammit, and as far as you can go on stock liners, tomei do an 88 mm head gasket to suit.
or if linered 88mm is 2.1, if you have liners though you might as well go 89-89.5 mm and use the 90mm head gasket from cosworth.
or if linered 88mm is 2.1, if you have liners though you might as well go 89-89.5 mm and use the 90mm head gasket from cosworth.
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Cheers dude!
red reading
Active Member
No problem,
red reading
Active Member
Just think of all the people who scrapped 87mm blocks from bad info given who now read this and realise they were salvageable..........850hp has been run on stock 86mm liners so 450 ish would be a sensible max on 87.5 mm, we actually bored a block out to see at a machinest mates and it's surprising how thick the liners are, touring cars in n/a form were running over 300hp on 88mm bores and a 82mm stroke, and that was a 54c gtir block and head......no trouble with rockers either!!
red reading
Active Member
Yep
I just spoke to Stu tonight a getting new block, reading this makes me want to look for some 87.5mm pistons again. Last time I looked I couldn't find them for less than 800 quid. The HG was about 120 so quite reasonable. Anyone found a decent price for 87.5mm pistons?
red reading
Active Member
Frs sport sell supertech for circa 400
These: http://www.frsport.com/Supertech-12...-Aluminum-Pistons-SR20DET-87-5mm_p_15923.html
Never heard of supertech. 4032 alloy would suit me. 9:1 compression ratio could work. Not sure if they're notched for a gtir oil squirter? Price is fantastic!
Never heard of supertech. 4032 alloy would suit me. 9:1 compression ratio could work. Not sure if they're notched for a gtir oil squirter? Price is fantastic!
red reading
Active Member
They look to be notched, if not get them done.
I was thinking similar. Any thoughts on the 9:1 compression? I'd like to run less boost nxt time so I guess I'd just need to fettle the ignition map accordingly.
Why have I never heard of supertech? Are they new?
red reading
Active Member
Supertech aren't new, they make valves and stem seals, valve springs (for kelford cams as well), they have been around for a while, just not advertised like the big companies in the uk, if you want high compression then fine, can always get the head worked to lower it anyway
What would you suggest on a 400hp engine 8.5:1 or 9:1?
red reading
Active Member
3071turbo...9:1, using less boost to archive the same power is always better for usability on the road
My thinking too. More capacity (0.5mm) and a bit more compression can only help spool. My last head had been skimmed a few times so was probably a little raised anyway.
Looks like Supertech it is then. Will email them about the Tomei HG. They mention the 1.8mm 88mm HG specific for a Gtir. Alternatively I just buy an SR20DET version and bore out the dowels like the Cosworth version.
Best get to bed, work tomorrow and kids getting up in about 4 hours.
As always Danny, thanks for your help.
Looks like Supertech it is then. Will email them about the Tomei HG. They mention the 1.8mm 88mm HG specific for a Gtir. Alternatively I just buy an SR20DET version and bore out the dowels like the Cosworth version.
Best get to bed, work tomorrow and kids getting up in about 4 hours.
As always Danny, thanks for your help.
red reading
Active Member
Glad to help
pulsar kid
New Member
interesting post guys, like your thinking on a 2.1, loads of the scooby boys favor this.
