Pavlo

Andy,

If he had Sti heads, then I would agree, but not with the UK cams, whose duration is around 210º

Paul

harvey

iTrader: (48)

I was not aware of that. Compared to what others?

I have a set of STi ver 5 cams for sale if anybody wants them.

Pavlo

Harvey,

Yours is probably invalid comparison as it's a 2.0. But Andy's torque was around 460ft-lb from memory, about 50-80ftlb down on what some others have acheived with similar sized turbos, but my results (to date) are with a 2.5 so they should be a little more torquey anyway (I am talking about torque on boost, not spoolup).

2.5 engines certainly use up the flow capacity much more readily than the 2.0 engines, and I think it's those engines that will benefit from cams (over UK units).

Some people say they're not needed, some people said you don't want a big Garrett turbo, things change.

Paul

S,M,G

I think you will find your cams have .365 lift to check this you need to measure the lift (top to bottom) should be about 1.822 then measure the basecircle (the round bit) should be about 1.458 subtract base circle from overall lift .364 then deduct your valve clearance and you have your lift at the valve. If you have this type of cam which i suspect you do then thats is the same lift as a DH22 wrc cam. One reason for using a top hat shim is that if the std type shim is used it can become heavy with a reduced base circle leading to valve bounce. Most issues regards radical ramps etc are an issue with engines that run rockers and there for have a rocker ratio and bigger valve clearances can resovle the issue. By resetting your cam timming with std cams you will gain more mid range and top end with little if any loss in the low down, and with ported heads the low down will also be improved. I have tried more profiles than i care to mention and have found that the subaru reacts differant to the norm with hot cams.

Pavlo

my cams are somewhat wilder than DH22s it seems, now I have found out exaclty what grind is on them!

Andy.F

Paul a VERY high percentage of these high torque/ uprated cam engines you mention have failed.
I also do not believe they produce anything like the torque figures on the road/rollers that they displayed at locked load on the dyno.
I'm sure if they did produce such high torque and could stay together long enough, then there would be more cars out there putting down some decent times to back the figures up !

Andy

ps Did it occur to you thay maybe, just maybe, I run my current level of torque on purpose ?

Pavlo

Andy,

I guess you didn't read the bit where i said "on boost torque not spoolup" as in, torque at a point after the turbo had spooled up, so at 4500rpm for instance. I am not talking about results at 3000rpm got by loading up the engine on a dyno. The cams are going to delay spoolup a little anyway depending on timing.

Put some UK cams in your car if they're that good, I have a set here if you want!

Paul

Andy.F

lol, are they free I'm changing cams eventually but not for more torque, just to extend the useable rev range.
I still consider 500bhp is closer to the 'cam change' point than 400bhp. I'll be able to prove it one way or another shortly as my 03 WRX will be going the 2.5 route on std heads and cams.

Andy

Pavlo

400hp the change point from what standard cams? And with what size of engine? And with what turbo? What stye of heads?



Paul

Andy.F

Until I see a pronounced difference in performance of the std cams on a modified car, I'll say ANY of them, same goes for the heads.
For similar spec engines, the power determining item is usually the turbo. Fit a 400bhp turbo and supporting mods to a 93wrx/97uk/99sti/03wrx and guess what, they all make around 400bhp ! I have found as big a difference between two same year Sti's as I have between Sti/UK/WRX of different years.
Now, build any of the above engines to take 500bhp and bolt on a 500bhp capable turbo and my bet is that regardless of heads and cams, they will hit very similar bhp.

Until you need to extend the rpm range to make serious top end power, or feel the need to blow gaskets/run bearings/split liners/drop valves etc then forget about cams would be my advice.

Andy

Pavlo

there you go folks, forget about cams and heads, regardless of what you have, it doesn't matter!

David_Wallis

Ill be interested to see what you can do with a 257 with std UK heads and std UK cams then

I have to say Im going to disagree with andy on this one!

David

Absolute Shower

Harvey, how much for the STi5 cams and what condition are they in? What sort of other mods will I need to fit them to my 02 UK heads?

Adam M

Hate to say it, but I tend to agree with andy.

Everyone starts throwing money at things left right and centre in the hope of making a little more power, but cams are quite an expensive factor in that, then heads come into it too.

If I had my time again, I would certainly not bother with headwork and cams, may just a little light porting at most.

I would be more than happy to go for 500bhp on standard sti cams, espcially given that the dh22 profile on mine isn't far off standard profile anyway.

You can go wild when at the top end of the scale, wallis for example, and his is making some serious power, regardless of what times it has shown so far. Do you really want to chase that high numbers, and compromise on low end torque, because from experience, I can say that 500bhp and spending far less money not eaking out every ounce of power is far more attractive to me.

Had I known I could stick an ej257 in with near on standard sti heads, and merely just change the pistons I could run 450bhp all day long, I would do it in a heart beat. It makes for a storming car ont he road which will trounce pretty much everything else there is.

Andy, just to check, do you dispute the 556lbft mine made on the dyno after the turbo had spooled up?

Regardless of times on the strip which it is not all about, is the figure unbelievable?

Am not going to state that mine hasn't blown up yet as I believe that to be tempting fate.

Absolute Shower

Its difficult to know what exactly is best here....as I'm not going for total bhp, I want a long and decent power curve with reasonable tickover, around 450bhp (as dont want uprated internals going bang at any time in the future)!

Do the injectors always make ticking sounds then? Must say, not sure if it is the heads themselves as it doesn't sound anything like worn "hydraulic" valves - not that its hydraulic, but you know the noise and how constant it is.

SecretAgentMan

I'm also going the US 2.5 route, on stock euro phase 2 heads - the turbo will be a Deadbolt SZ53, and I'll swap pistons (might go for rods as well, but it's not likely)...that's about it, oh and a set of nice 740 cc injectors from Andy (cheers).

I haven't really made a proper plan yet, but the goal is a decent, relaxed 400 hp on regular pump fuel (with a bit of headroom if I want to push it).

I'll follow Andys result with great interest, and will probably do a half serious attempt at the dragstrip after everything is sorted (don't care about rolling roads, trap speeds says it all).

/J

Absolute Shower

Would be interested in your results as can't see my motor being sorted for a while...

P20SPD

iTrader: (1)

Standard heads will do then IMO. I only changed, because i wanted the higher rev limit, and the STi5 valvetrain was deemed to be a little stronger than my UK valvetrain.

David_Wallis

Steven,

In that case why have you had the chamber re-shaped and ported??

Im not saying wild cams are better, but I am saying there are gains to be had..

if we use the BHP per £ then they might not be the most effective mod, but the main thing people need to decide is What they want from there car, I suggest that the Sti Cams are considered as a good all rounder (maybe even a comprimise?)

My cams allow alot of flow through the valves but sacrifice Idle and very low rev performance, but they arent timed up properly, nor do you drive the car whilst its idling (IMHO)..

its one of those debates that will go both way IMHO.

David

Mr J

Well I think Rigoli did runs standard cams...and sick amount of boost like +40psi

i was going to get STI 5/6 heads for my 2.5 converson, but stuck with euro/UK heads It was Ok up in the rpm range but willnever now it would have felt with STI heads in stead....


My new block will need cams for sure...as don't like the idea to puch 70Ibs o air thourgh stock heads..., and stock heads have a bad habbit of shooting out shims when running als..


Jan

Andy.F

No Adam I don't dispute that, I do however wonder if it actually ever produced that figure on the road though ? That was produced at locked load (like foot on the brakes ) at circa 4000 rpm and although I have never actually driven your car, I assume on the bigger turbo it really only got going with full boost at around 4k when running through the gears ? Which is some 1000 rpm later than on the dyno.

David, what torque did yours make at 4k on the rollers ? just to get some comparison of static v dynamic torque outputs.

Andy

David_Wallis

andy.. the graph isnt to hand..

Edit..

got the graph.. LMFAO I thought a lot at first... around 240lbft at 4400 if Im reading it correctly.

400 odd at 5000 rpm

David

Andy.F

Thats because of the fast run up rate on the rollers, kinda like 3rd/4th gear i would guess.
If you locked the rollers, then planted the throttle at 4400, you would be able to show a much higher number but it would be meaningless really, that was the point I was trying to make to Adam. You can't compare dyno/rollers.

Andy

Pavlo

Adams turbo on mine made full boost before 4000 in 3rd gear, that's all I can remember, different turbo to David's

Paul

P20SPD

iTrader: (1)

David, purely because, as you know, my goals were a little higher than AS's, ie over 500.

David_Wallis

however in hindsight your car needed a lot of boost to make the power IYSWIM.

P20SPD

iTrader: (1)

Indeed, but we also know, it was never truly running right

Adam M

Andy, I see what youj are trying to say.

on the road it was making pretty much whatever boost I asked of it in 2nd/3rd gear at about 3700rpm.

Of course this is all with the old turbo.

It never felt laggy in the slightest, but I do prefer the newer small turbo.

David_Wallis

Yes I know, all im saying is that I dont think its as clear cut as people think, Ill explain when I see you.

MorayMackenzie

Adam,

"The rev limit of the older heads (version 1 and 2) was due to the weight of the pistons not due to the supposed hydraulic lifters which they don't have. You will have solid lifters on your heads which given the right pistons in your short block can still happily rev to 7500 or 8k rpm. (I wouldnt bother personally)."

If this is really the case, then why do the STI heads, which were designed to support higher engine speeds, use low inertia valvetrain components and, I suspect, uprated springs?

How will the UK heads manage to avoid valve bounce at high revs with the heavier follower and shim mass and, I suspect, lower spring rates?

Even if the spring rates were the same in both setups, the higher inertia in the UK spec valvetrain is more likely to overwhelm the springs attempts to follow the cam profile at considerably lower engine speeds than the STI valvetrain would. If the spring looses the batte to keep cam and valve in sync with eachother, then the heavier overbucket shim will be shown a potential way that it could remove itself from the equasion.

It is possible to use loctite or similar to help hold overbucket shims in place, but that will not be a cure for a valve bounce problem at high revs, it merely helps retain the heavy shims in their normal location.

Moray