16 replies to this topic

[mini_me]

Have just put a 1275 turbo engine in my chelsea, and have found a set of 1380 turbo pistons in the garage that i forgot all about?! The engine hasn't been set up so i was thinking would it be worth while fittimg the 1380 pistons? I no i will have more off boost torgue but will it be the extra work?

Also i have a full stainless off a metro turbo but the front pipe caught on the bulkhead at the bottom between the subframe. Would a front pipe from avonbar be any different? Also has anyone used a race can on their turbo? Iv got an old R1 can lying round.

Cheers.

[Wil_h]

So you've just put an engine in your car and now you want to take it out, take it all to bits, get it rebored, put it all back together again, then put it back in.

Perdonally, I'd leave it where it is.

As for exhausts, the Avonbar (or more likely maniflow) down pipe is the one you want. It's designed to fit,so it will.

Assuming that the bike scielencer is the right size tube then I'm sure it will work fine. Not sure what it would look/sound like though.

Wil

[mini_me]

Well it wouldn't take to long to take out, just woundered if there was much extra power in the 1380 as iv'e never had the chance to go in a 1380 let alone 1380 turbo? Thought it might be worth while doing now while its not running instead of changing my mind later on?

Cheers.

[mini_me]

Also would it be possible to use the 1275 turbo head with the 1380 turbo set up?

[Turbo Phil]

I'd leave it alone for the moment. Besides going to 1380 is going to cause more problems when you have to take a load out of the head chambers to get the compression down to a sensible level, the situation will be even more difficult if you want to run high boost levels.
Get your engine up and running and save your pistons for when it needs a rebuild in the future.

Phil.

[mini_me]

OK sounds fair enough. didn't realise the head had to be worked, thouht the piston hight was just shorter. IM also building up a 1275 turbo engine for a friend because he's on a budget we're using my old spares, but the engine he's got has a piston through, but the bores are good. Have seen standard pistons on morspeeds site for £150, are these any good?

Cheers.

[Turbo Phil]

I doubt the piston height will be shorter, even if it is, the piston sitting down the bore at TDC is far from ideal. Unless they've got a huge dish, or you're going to run very low boost, then you'll have to work the head chambers to get a useable compression ratio. Obviously the higher boost you plan to run the more you'll have to drop it.
For a decent cast Turbo piston i would try the Minispares Mega pistons. Though you'll have to go +.20.

Phil.

[MRA]

Phil didn't you used to work at Mini spares ??

1380 Turbo if you use the 73,5mm Omegas with an 11cc or 15cc dish, then 26cc head chambers will allow 12 to 16lbs quite comfortably coupled with the extra torque you WILL need a 4 pin diff unless suicide is an option !!

The higher the final drive ration I.E 3.11 is good with 13" wheels and tyres gives good alround traction and top end, just make sure your clutch is up to it !! :grin:

Good luck its worth it .....

Cheers

[AlexF2003]

What clutch would you run with that MRA?

Alex

[wolfie]

i was not aware omega's came with a 15cc dish ? i thought it was 7cc and 11cc ? theres only a couple of people that i am aware of that have made the 1380 turbo work well and they iirc have used alot less than 16 psi of boost

imho i would shy away from 1380 turbo untill you have sorted the car, also as someone has already stated you would need to machine the chamber and i may stand corrected but i am sure its going to be more than 26cc, having the head reworked is never cheap if done well so again the expence may be an issue

other considerations are going to be what you use the car for? a 1275 may be more reliable than a 1380 in the long run

[Turbo Nick]

sure you can get forged omega's in 15cc. but JE and Accralite are now both doing 18cc forged for around £400ish

[Wiggy]

Why is it harder to get a 1380 Turbo to work well, opposed to a smaller bore?

[minimole]

i think it is something to do with the fact that cylinder walls become quite thin and can flex if you are not careful. Although saying that there are 1380 turbos about that work fine.

[Turbo Nick]

i think it was mainly due to not being able to get the CR low enough, but thats sorted with the 18cc pistons now.
i'm not so sure about all that bore flex talk to be honest, sounds like an old wives tale to me. but we'll see if i decide to go ahead with a 73.5mm bore on my next build.

if it breaks then i'll believe it...lol

[MRA]

What clutch would you run with that MRA?

Alex

Hi,

I have run several clutches over the years:-

I have a Paul Ivey Race aluminium flywheel (Flywheel 5lbs & backplate weighs in at 1.25lbs) with that I used an orange diaphragm and a race/rally plate

currently I am using an ultra light steel flywheel and backplate with a grey diaphragm and a race/rally plate

I have used sintered plates in all of the above, whilst the "grip" is great the gear changes and start off can be a lot sharp i.e. like a switch - either on or off !!!

You can get used to it !!! But I was at that time using it to get to work in rush hour, my left leg is at least three time bigger now :grin: :grin:

I have been running 1380cc turbo engines since about 1986/7 without any major problems, my first head was an AVONBAR unit which I used for quite a few years,

I say GO FOR IT :grin: :grin: :grin: