ok, already have a shitload of stuff on order, now this top end/ turbo rebuild is taking on a life of its own.
Tell me your thoughts Poncams vs wolf cams, solid lifters or not, im thinking new springs and arms too.
What the fuck, Im gonna rip open the bottom end too and get new main and rod bearings, which means machine shop work, which also means new rings and some honing of the cylinder walls.
Also your thoughts on just putting in the apexi gasket without re decking the head and block? Should be fine? havent checked for flatness, but assuming its ok. will throw a level on there and check when I get them seperated.
Lots of questions to answer, your help/opinions please…
btw, horsepower goals are 300-400. Trying not to get into crazy shit, costwise, although i’m already in it deep.
I’m looking into this aswell. There are a few good threads on Zilvia, NICO and SR20Forums.
First off, what turbo are you using?
Tomei Poncams are probably best suited for T25/T28, however there is Poncam for SR20DE that is identical to the S3, with 260* duration and 11.2mm lift. Unfortunately, no one has posted their experience with these in a RWD DET.
If you are using GT2860R or GT2871, a 260* or greater duration would be better suited. GT30 and up, 270* duration or greater.
CodyAce made a good point that for the cost of getting into Procams / HKS Step 2 and springs, JWT cams are more cost effective. I am a firm believer of putting your money where it counts, so money on valvespings is sort of wasted when many others have used JWT S3 and S4 with no issues, pushing 400whp.
Personally, I am leaning towards S3HL, S4 or S4HL.
In regards to the metal HG, you need to check the deck and cylinder head throughly if you plan on installing the gasket without having those planed, refer to the FSM for that. Metal HG’s don’t conform to irregularities in the mating surface like the OEM fibre gasket does, therefore, they require a finer surface finish. If you are having the block honed at a machine shop, why not have it the HG surfaces machined? That is the only thing hold me back from installing a metal HG, disassembling the engine and doing it right.
As for solid lifters, I have not looked into that. Probably for high RPM / HP applications where the hydraulic lifters cannot keep up.
I would pick a cam that suits your turbo, for example I have a gt2871R.64 so for cams I went with hks step one, same spec as pon cams, my setup is built for fast response and spool. I also chose 9:1 compression pistons for more response as well. with the turbo and cam setup I am running my power band will be in the lower rpm range so I don’t have to rev the piss outta it for power. by doing so I have no need for solid lifters as my redline will lower then 7500rpm. I did however use bc springs and retainers as well as rocker arm stoppers for safety. hydrolic lifters will be quieter and shouldnt require reshiming unless a valve job is done. if you block is straight have your oil pump/ timing cover shaved down to match your block height and your gasket will seal better.
I will be running the stock Garrett GT2560 for now. Rebuilding it for reinstall.
btw, I didnt know that rightdrive is a tomei dealer, right here in town, and they honour the US pricing without any extra brokerage charges or duties. Not saying that i’ve decided to go that way, but thought it would be good to mention.
I’m taking the block and head to ajax racing engines for a look, which will give me some more idea on direction too. Is there any value to porting and polishing on these engines in addition to a cam change?
Looking for power in the mid to high range, so I don’t have to rev the shit out of it to see some power.
I choose not bother witha port and polish when I rebuilt the head, from what I read the sr head flows pretty well from factory. By the sounds of your goals I would not bother but if you have the cash I’m sure there are improvements to have. Deck the head though if its going to be at the shop.
im trying not to get too crazy with costs so im not doing the pistons and rod swap. Just new camshafts, rod and main bearings. Target hp is 300 to 400 to the wheels. If I was going targeting 600 hp, I would be doing alot more stuff.
What turbo would you match to the procams, and what are the benefits of going that way?
cams are fucking cams! brands don’t matter. durations and lift are the only variables. JW has good explanation (on their site) as to use what cam for how many ponies and there are many dyno graphs [google] stating the turbo they use. but a rule of thum (from buddys genesises and subbi builds) is: for mild power TURBO cams is to have intake relevantly the same with only 10 to 20 advance opening and exhaust more retard closing to help spool, meanwhile more lift (10 to 30% more) and overlap mostly the same. you can flame, or you can listen. but no matter what u do, if you going solid lifter you NEED good springs or valve-float away ur engine byebye.
FUUUUUUUU!!! Pulled my turbo apart, and now im finding that I think I have the ball bearing unit that is not rebuildable. (I can’t see why not though, there are only 16 fucking ballbearings to replace and then the end seals. Not that hard!)
Looks like ima doing a new turbo upgrade !!! Any good(cheap) sources for good trubos? the t2560 seemed to be good only for very low 300hp numbers at best anyways from what I read on garretts website.
Knowing which cam to select is really hard stuff if you don’t have solid knowledge in this area. Opinions on this subject are all over the place. Its hard to know who to trust, unless you know for a fact that they are running the “recommended” setup in their cars and are seeing provable results from the upgrade.
Cam manufacturers give surprisingly little info on real hp gains made by using their cams on a specific setup. It seems like a 5-10hp gain can be made from the cam change. It seems that this would work with a larger turbo than stock and a system like nistune vs an Enthepaly tune to get to get to target hp.
UPDATE: Currently leaning towards the GT2871R with .64 exhaust which is rated at 250-400hp. This is vs the GT2860RS (disco potato) rated at 250-360hp. Any opinions one way or another? These will be setup in the T2 style to use the existing manifold. It doesnt seem worth it to go for the T3 intake which means a new exhaust manifold, which seem prone to cracking…what do you think? I guess more air equals more power, but I read that the stock exhaust manifold can easily get to 350hp and room for more.
Ok, so go with a t3 housing and the 3071 with a .61 a/r?. What exhaust manifold would you be looking at? At 1500 a pop plus all the screwing around to replace engines , I don’t see the value in going through them frequently. The stock gasket can’t handle all the abuse of a high hp application like that. Doesn’t it make sense to do it once only? At least change the headgasket and use arp studs.
most modern cams are symmetric therefore their pitch curves are the same. non-symetrics were used in old amercan engines to compensate for big hydro lifters and or rockers…(as far as i know).
Most modern cams are either harmonic or cycloidal motion. and in either one as displacement go up and distance between dwells decrease, acceleration and jerk increase. all this means you need springs with more potential energy (stiffness) to stop the momentum the moving part (aka valve float).