supercharger to turbo
Turbo Mini Forums

Since having built the supercharged engine and getting the car on the road this year I'm now starting to get an itch to start using my spare engine for a turbo build..... looking for about 160bhp

I've managed to pick up a few parts for another build through the years... straightcut gearbox,x pin diff. 2 t3 turbo setups including pleniums ect, 29.1 turbo head (currently on the supercharge build but can be sacrificed.
still a few items to pick up Cam, flywheel ect
The engine is a standard metro engine bores are ok but will be getting them bored +20 thou.
With using the 29.1cc head and a set of +20 10cc cast omega pistons I work out my cr would be about 8.2 cr
Would this be abit low the agricultural t3? As I've read they dont boost until higher up in the rev range and people advice the escort t3 to sort this?
Or could the deck height lowered to help raise it with put affecting the squish to much?

Personally Id ditch the T3 in favour of something more modern like the GT1752 or if after big power the 2056.
Phil may be able to help you out increasing the head cc's to allow you to deck the block to provide better squish.

Shane

Edited by shane on 10th Dec, 2020.

cheers Shane,
not looking to increase the head cc at the moment as its been brought out to 29.1cc so any more I think would be pushing it

I did think about the GT1752 and making up the adapter plate to fit the t3 manifold.
how would the gt17 react with a cr of 8.2?

cheers struan

I guess the first question to ask is what's your target HP / car used for?

Shane

8.2:1 should be pretty decent with a gt17, with a good intercooler you could be looking at 180-200 hp at 20 psi.

by my calculations, flushing the pistons with the block would bring you up to about maybe 8.6:1 which i would be happy with for 160hp assuming a good intercooler, turbo ( like the gt17) and fuel.

if you did need to find a couple of cc you could take a couple of cc out of the pistons.


what sort of fuel octane can you get over there?

Shane would be happy with 160 but theres always room for more haha
Itll be a fun toy with plans of drag and track days..

Cheers Joe for clearing that up looks like I'll be changing plans and going for the gt17 then
A good intercooler is on the list of parts..

Dont think the fuel is much different up here in Scotland compared to your over the border haha

I know a rts clutch is a must for the power, any recommendations on other parts for running up at 160?

Edited by Struanbedgar on 11th Dec, 2020.

it blatanty says aberdeen there, for some reason i was thinking you were from germany ! lol

parts wise, you look well covered, SC box, RTS, X pin diff,

the only things that spring to mind is make sure you have the better (later) gearbox casing with 3 bolts holding the main bearig retainer in, and personally I'd aways use ARP rod bolts,

mapped ignition is a good idea, but not essential, can always be added later anyway.

If you go GT 17, it may be easier to flog the metro manifolds and T3's and get a fusion fabs manifold so you dont need to cut the bulkhead (unless its already done of course)

I thought you where gonna austrailia since I'm running a sc12 supercharger haha

Sc box I've got one laying about with a xpin, megajolt currently running the other engine and arps are on the list.
Rts is on the list to make... what's the thinking of lightened flywheel on turbo engines?
What about cam choice?? See alot of different opinions on these
Yeah I was thinking about selling them to fund the fusion manifold and turbo...
Do you know a going rate for them as dont want to rip anyone off on the old fleebay or here

lightwight flywheels are not really needed, or at least not mega light, its certanly worth taking some wight off, personlally i'd just use either the mini spares or MED outer verto section, its a chunk of weight off but not enough to affect drivability.

cam wise, just nothing to hot, IIRC 180hp at 18psi has been done on the NA MG metro cam, the kent 274i looks good as its got a wide lobe spread to limit overlap ( overlap and too much duration are the enemy really) short list would be...

roughly in order
Std turbo cam, MG metro, SW5, Kent 266, kent 274i, phase2 turbo cam, RE13T

not sure on prices, TBH i would just stick them on ebay and put links up, let the bidders sort the price! that said theres a metro manifold on there for 115 quid right now

Joe has pretty much covered everything. My only comment would be, if your thinking of big power at a later date then cover the necessary pre requisites now while building the engine, its easier/cheaper to build it right once.

Shane