Piper Cams
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Just out of interest was the 13.5 with 18 psi and the gas? I have some gas to put on my car just need to find some better tyres!

Sorry to jump thread but hopfully this will help ministef aswell.

Am running the same cam(266) and standard t3, id like to think the turbo isnt the limiting factor but as a gt17 isnt a direct replacement is there anything to do with the origanal to help power. Ive had a very nice exhaust system made and dont realy want to start altering it.


Rick

you can "hybrid" it with an rs turbo exhaust housing, which is a .36 A/R rather than a .25 like the metro, aparently some rebuilt units end up with the .36 is the std one is cracked.

dunno what the escort compressor is like, i woul have thought it would be ok to stick the whole escort turbo on.

i'm with you on that one rick, it is certainly the cheaper option after a long expensive build. The 13.5 was with gas, it was weighing in at full road spec, and i actually think i have stones for wheel bearings as its so difficult to push (looking into that at the weekend) I will speak to CR turbos and see what they suggest?

stef

"Cars are a lifetime of pain"

the rs turbo escort t3 has the same 45 trim t3 compressor as the metro but has the larger turbine housing. the next one up is the 50trim t3 wheel as found on the saab t3 from the 900 16v which has a 0.48 turbine housing but this could be swapped for the smaller 0.36 from the escort

So lets conclude, If i change the ar of the turbo keep the cam 266 and port and flow the exhaust manifold and exhaust elbow? ishould see less restrictions top end? If so that seems the easier option.

"Cars are a lifetime of pain"

Might see some lag creeping in an low revs though mate.

Warning:Stig in Training

Lets get this straight; the duration and overlap optimum for a TURBO camshaft profile is DIFFERENT than for a NA profile, no matter how "mild" it is.

I personally don't see the point in struggling with a NA cam profile, when there are plenty of (and one especially) well developed and proven turbo profiles out there to use.

iam a fan of the kent 266 for turbo road application T3 tony is running this cam and his motor is turning out 180 odd BHP at 13 psi of boost

doing the elbow and the manifold are worthwhile mods and gains will be had all throught the rev range especially mid to upper limits.

the ultimate road cam is the avonbar phase 2 and is well proven...

Edited by BENROSS on 18th Jul, 2008.

certainly T3ton have a nice engine , but he could certainly be better with the correct turbo timing , 106° lca is a performance road na one, genuine leyland performance road cams are ground at 107.5° turbo ones at 110.
with the price of cams I can't see the point to use a n/a profile, certainly it can work but certainly less that the correct one

I agree with Mr Fenton.

You have a N/A cam which has port sizes at a ratio which suits non-boosted. In order to make lets say, twice the exhaust gas come out of an exhaust port, you have to change some stuff.

I would say looking at the restrictions first, valve seat, exhaust port (by bosses) giving it a bit more radius here and there. You are going to want it to open as early as possible and lift as high as possible. You can partly achieve this by using a bigger exhaust valve but since we are talking about cam swapping, you make the sacrifice of having greater overlap due to increased exhaust duration. Assymetric cams are the best, Kents are and a lot of Pipers aren't. I reckon that (personal opinion here, and a bit of experience) the A series is an under exhausted engine anyway and a bit extra exhaust works very well. See MG Cam.

For a FI engine, I'd look at the MG cam first, then the piper 266, then the Ph2 Avonbar cam. The 276 is in this ballpark but is starting to bugger up by having the inlet open too long relative to the exhaust, which the Ph2 does perfectly. Ph 2 is the way to go.

I'm personally going for even higher boost and an MG cam this time around.

I would stay the hell away from any piper cam or that bloody SW5 on principle. Although, I gather the latter are the best cams in the world ever, from your grannies auto to a sprint car...

Bugger off, I'm getting there.

Ok just to confuse things, if were going for out and out power and arnt botherd about driveability rount town (just track car) what cam then???

Rick

you can turn around it as many times as you want, if you want power , you need boost, which need exhaust to drive it, thus increasing exhaust pressure and reversion,the low c/r doesn't allowing a large inlet window to come on cam then:
the only thing on which you can work is lca and exhaust duration,
with this in hand , take a fast road cam, keep his inlet, then a semi race cam for exhaust spaced 110 °, then you have a phase2 cam, you can have this grind with kent cams, or any other, after all it's exactly the base idea of speedwell when they took the 998 cooper inlet crossed with 731 exhaust, thus great idea applied by mg for their best road cam, the mg n/a.... 6648 grind , which is also used greatly in 998 seven guess why it work well on a turbo. having used a 643 cam for a race n/a engine I would guess that it could also be a good idea to try a 731 inlet with 110° spaced 643 exhaust ... etc etc
at the end actually what does work is mg n/a cam ,avonbar phase2 , and from some that did use it (Jukka for ex) is vmax cam (though it was 276 in 286 ex crossed at 108).

right, i'm going with everyone on this and ordering a phase 2 cam.......getting a gt17 / gt20 (depends on sizes and avalibility, making my own ss manifold, and stick it on the rollers again. turn the boost up and see what happens! i'm still on cast pistons mind, but i do have oil squirters? its only a weekend toy, so i'll see what happens, thanks to everyone for there help, mr fenton, fab.

Cossierick, i think were in the same boat, i'll let you know what i do.....

"Cars are a lifetime of pain"