16 replies to this topic

[benfredjosh]

hey i currently have a 1275 spi which i hope to covert to carb & turbo if i convert my spi engine to run on the t3 turbo with the turbo carb will i need to use a turbo camshaft??

[ditz]

hey i currently have a 1275 spi which i hope to covert to carb & turbo if i convert my spi engine to run on the t3 turbo with the turbo carb will i need to use a turbo camshaft??

nope
you the only internal things you will need to change straight away (if you planning on using more than 7psi MAX boost) are modify the head to lower CR and or run turbo dished pistons

[benfredjosh]

thanks ditz do u know ruffly how much it costs to lower the compression in the head? i have quite a few machining workshops close by? was wondering a price would hate to go in and be astounded! lol will the spi engine cope ok

[DaveCoxon]

I believe the SPi is 10:1 ?

Yo should aim at getting it lower - say to 9:1 to give you reliability and scope for running on 95Ron fuel easilly. Morspeed will help you out on the chambers.

No other issues really - apart from changing the plugs and fitting the turbo ignition system, and the bulhead box, and the exhaust system, and the.....

Have you looked into getting past emissions come MOT time?

[benfredjosh]

thanks dave
ur a very knowledgable person! lol i know i'lll hav to do other bits! but what the hell!lol i should buy another 1275 carb engine so i can change that 2 turbo so i have my car on the road all the time but hmm i dont know yet!

[DaveCoxon]

Other thing to consider; the clutch in yours will spit it's dummy out probably with less than 7psi depending how worn it is.
The 'turbo' verto clutch will be good for 10psi - maybe a tickle more?


Just checked on the http://www.mancheste...k/technical.htm section, and it says there were two CR's on the SPi's (i didn't know this)? :saywhat: :saywhat: :saywhat:



12A2DF75
9.4 : 1
1991- onwards Single point injection, manual transmission, 95RON unleaded only.


12A2EF77
10.1 : 1
1991- onwards Single point injection, high compression., 95RON unleaded.

[Don't Panic]

95RON unleaded only? surely you can use 97 too

[ditz]

95RON unleaded only? surely you can use 97 too

or higher, higher the CR higher the octane you need to use.. hence why cars running on methanol have insanely high CR's

just while i think of it another little fact i found out recently (posting this because somebody on here thought the jap import cars had troubles with detonation on our fuel)
if its reccomended that 95ro or higher fuel be used (reccomendation from the japs)
thats the equivilent of about 90 over here :wink:

[chairchild]

any non-cooper SPI has the lower CR of 9.1:1, and a naff cam that halfway between an A+998, and a 1275. Its neither here, nor there.

So if it's a non-cooper, you shouldn't need to worry about the CR, but just swap the cam for a standard 1275 item to up the performance

Clutch should be ok for upto 90Bhp - as long as you dont keep dumping the clutch to get wheelspins that is....




also, I think the metro turbo's were something like 9.1:1 CR?? And they ran 7psi from the factory

[DaveCoxon]

you can't simply say 'clutch will be good for 90 hp'...

The metro turbo had a 'torque limited' 85lb ft and this used an uprated clutch. :wink:

It's well known that the standard clutch is marginal for a hot nat-asp motor. Stick a torque-maker into the equation and you're already past the limit.

Where did you get the 9.1:1 CR? I can't see any modern engine - even an a-series being this low - I could be wrong, but it sounds tooo low.
Metro turbo was 9.4:1; standard metro 9.75:1

[chairchild]

well, I've got my spare 998 that's got 8.3:1 if you'd like to measure it :wink:

and I stand corrected on the metro turbo CR, but I knew it was above 9:1




also, I've been told by a couple of reliable peeps, that they run their tuned engines with a verto clutch, and they run at around the 90Bhp level. But any more than that, they just throw on a pre-verto for ease!

[DaveCoxon]

ho ho ho (must be christmas)!
I thought the discussion was in regards to 1275 units - especially injected ones?

And regarding the clutch - TORQUE is what you measure the potential of clutches with - NOT power.
As any idiot knows, turbo motors make more torque than nat-asp units - hence why they make more power for the same RPM.
You'll be lucky to get over 100lb ft out of a decent stg3 1380. Stick a turbo on a bone-stock 1275 and you'll make loads more torque than that with just a reasonable boost...

Stick to what you know son...

[Sprocket]

Stick to what you know son...

Thats the one :cheese:

  any non-cooper SPI has the lower CR of 9.1:1, and a naff cam that halfway between an A+998, and a 1275. Its neither here, nor there.

As to the Non Cooper SPI having a naff cam, would you say the same of the 1275GT cam because thats what it baisicaly is and the CR is 9.4:1

[benfredjosh]

wow lol thanks for all this help its blowing my mind :S lol to much information lol! no seriously thanks folks dave i'll pm u when i recive my stuff thanks all!

[Leonard]

putting in the standard metro turbo pistons will lower the CR provided that the dish in the current pistons is smaller