SMG

If a few people are interested i will put up some pics of valve
timmimg which is poss with engine in situ, and a few block mods.
Steve

ustolemyname??stevieturbo

iTrader: (1)

Always interested. Wondered why you had been quiet for a while. Any more info on the high lift cams yet steve?

SMG

Stevie, just trying to get some reasonable valve and shim arangments sorted, looking like some staneless valves running top hat shim and light weight buckets, trouble being all the std valves
including sti are two piece hardened steel shaft with fusion welded
staneless heads dont trust these.
Steve.

UkLegacyT

post some piccies steve, im interested too

ian

SMG

SMG

ustolemyname??stevieturbo

iTrader: (1)

I like those pulleys. What are you doing to the block?

Pavlo

It looks like a brass insert with a ring groove.

Paul

David_Wallis

why do you machine the groove for the wire rings into brass??

I just assumed that when this is done it would be done into the block...

How clean is under the bonnet??

David

ustolemyname??stevieturbo

iTrader: (1)

How easy to get at is that dial guage ????? not. Any volunteers with an engine dyno, to play with the cam timing??
And since I mention it... How much does an engine dyno unit cost. Just the basic necesseties relating to the actual dyno. All the controls/ fuel supply etc etc can be done DIY to an extent



[Edited by ustolemyname??stevieturbo - 9/20/2002 2:24:56 PM]

David_Wallis

stevieturbo

Nice idea....

Might have to look into this...

David

Adam M

have heard from a few people well into mapping of our type of engines, that vernier cams are not worth the effort.

Had to ask this when considering my engine build. Apparently anything in the range they accomodate for is more hassle than anything else. They saw at most 5 to 10 bhp gains on various dynos by playing with the timing inbetween what is allowed by movement over a whole tooth.

In short, simply not worth it.

Prodrive dont bother when mapping their wrc engines!

only people who said it was a must were kent, who make and sell them.

I have not written off the idea, but have not heard a positive report from anyone whose opinion I know to be worth listening to (with the exception of kent, but marketing bias rules them out).

SMG

The bronze insert takes more heat, the groove is for a gas filled
wills ring the block is moded to take alloy nikasil liners. Adam
what you have heard about prodrive and what is happening is two
differant things. You dont just play with cam timming to get big power
increases, for example your std pulleys say are ment
to give a full lift @112 and overlap of 20 degrees, you have just got your hot cams with full lift @106 degrees and overlap of 40 degrees that will put cam timming 6 degrees out and thats not even considering mass produced things like deck hieght head thickness
dawl possition of cam and cam pulleys gasket types you may want to change. In short you can move your power band about by adjusting
valve timmimg even more so with multi cam engines. An other example, you want low down torque and plenty of mid range, you
have your turbo sorted 9:1 shortish duration cams turbo is on good boost by 2000rpm your going to get good cyl fill at low rpm, but
your cam timmimg is wrong and you have loads of overlap and all
this low rpm cyl fill you have is getting in the cyl and going
straight out the exhaust valve= bad low down cyl fill, torque is obtained from cyl fill its just where you want to obtain your power.
Steve

ustolemyname??stevieturbo

iTrader: (1)

What sort of cam specs to the WRC/Grp A cars use, and would they be suitable for a road car, bearing in mind the rally cars are all about mid range due to the pathetic restrictor they have to breath through.
Altering cam timing by moving a tooth on the belt is a tad rough i think. If 5-10 hp can be got from timing in the cams on a car, then surely it is worth it, especially if you are going to lengths elsewhere on the engine. There must be gains in torque too.
Its still strange why there is so little info about regarding uprated cams for subarus. There must be good gains to be had with different profiles, although I do think that I read somewhere that the Rigolis use standard camshafts...I dont believe them somehow. I want more lift, more power, more torque...everything, but more importantly, more information.
Have you tried any different profiles yet Steve??

Pete Croney

I know for a fact that Gp N cars have different cam timing. I would suspect that the same principles are used on Gp A and WRC engines.

As these cars run inlet restrictors, they are dead beyond 5750 (Gp N) or 6500 (Gp A/WRC), so there is no point having cam timing that produces max power at 7800 rpm.

I have driven two cars with revised belt timing and they were staggering in the mid range, but gutless over 6500.

As SMG says, you just need to decide where you want to concentrate the engines optimum efficiency.

ustolemyname??stevieturbo

iTrader: (1)

But a road car isnt tied with the restrictor, which would allow it to breathe a lot easier at high rpms. Surely Grp A cars dont run standard profiles, with just altered timing?? If the Grp A cars didnt have the restrictor, then whatever cam they are using, Im sure that they would rev high enough for any rpm junkie, and high enough for any road car. I see no reason to rev a turbo car to anything over 8000max on the road. If you cant get enough power before that, then something is wrong.