Best Camshaft for11.3-11.5:1 compression gsr?
 

Im not sure how to pick a camshaft, The gsr i built had a little higher compression then i expected due to the cylinder head being milled more then i expected.

I used a compression ratio calculator and i guess im running around 11.78:1 it says. Idk if thats right as i am running a stock gsr ecu and 91 octane with no detonation, runs great up to 8k, been driving for 4k miles at 28 mpg... I know that pump gas is safe for up to 12:1? Also it seems REALLY high... idk. Maybe i did something wrong?

Its a guess... and im not sure how much head was milled really, all i know is that i had to advance my cam timing 2 degrees on the aem tru times (on the cam gear it goes up to 10, so im assuming a +10/-10 gear) to get it back to stock (which everyone says for every .011" milled its 1 degree advanced. So im assuming about .022 milled.

Also i have usdm itr pistons (oem) in .25mm overbore

So assuming a possible 11.78:1 compression ratio....What cams should i run?

I also have ITR Dual row springs on the intake, as well as gsr intake switched to rear. I have the oem gsr retainers if that matters.... what can i safely rev to? im thinking 9k?

also, just looking for opinions from guys that have actually TRIED cams they are recomending, WITH TUNING, not just slapped itr cams in and it felt like it pulled hard...
if u know what i mean haha

thank you guys :you rock:

i run sk2 stage 2 tuners n they pulled very good in my lsv. made 180whp at locash with a very simple build so id rec those or stage 3's if its a daily

yeah its a daily, i cant believe my compression is that high, seems wrong to me.... idk lol i was shooting for a point lower then that lol. o well i guess boost is out of the question now.

is there any way to confirm its that high? i dont think a compression test metters due to the inaccuracies of the guages haha. i am running a colder plug though, the heat range for the itr, a 7 i wanna say?

am i missing something?

i also dont wanna overcam my motor due to a wrong guess.....

A good quality gauge will give you consistant numbers, atleast mine does.

12.5.1 comp will still work fine with 91 but it better be tuned. Atleast a/f checked to make sure it doesnt run lean, you can always adjust advance and fuel later.

A good choice for you would be a tuner2 or like a pro1. BUT with your valve train, i dont think it will hold up to the pro scale cam. Im sure it would but i wouldnt trust it. Especially 9k rpm

Im getting ready to drop pro2's in an 84mm 12.5.1 motor but it has a fully built ported head.

yeah thats what i have been finding out. itr valvetrain only seems to be good for itr cams haha... who knew...

well, i was thinking of the skunk2 tuner 2's, but i will need the springs and retainers.

what do you think my power difference will be with a CTR cam versus the skunk2 tuner 2's?

is it worth the extra money to try to locate a set and valvetrain, or should i just pick up some CTR's? (they seem pretty easy to find.)

what is the best valves to use? im thinking of blackworks lightweight valve and duel springs? and could i just use a stock b16 or grs cams or should i just buy cams cause im looking to run 12:5.1 around there and could i just use stock rods

Power might be 10 to 15hp just a guess, you wont know unless you run your own test. Either way, with either cam, I would find a quality valve train.

I would recommend supertech or ferrera or manley, spend the extra and save yourself a headache for longevity. I personally wouldnt trust anything else regardless what anyone says and thats just me.

You can use stock rods yes, but you best get arp rod bolts and have the rod resized, also have the rod bushed for a floating pin as this will free up some rotating drag creating less resistance.

ITR and CTR valve springs are the same. I can run CTR/00-01 ITR on that valvetrain and be fine.

Just curious if the extra power is worth it because my compression might not be high enough to really take advantage of the skunk2 stage 2's

10-15 sounds like it might be worth it. im not expecting an accurate answer haha, thank you for your time. ill let u all know what i get out of it.

You can also do a flat face valve to up your compression alittle, not really suggested cause it adds weight to the valve head but it WILL up your compression a tad.

Even if they itr valve train works. I personally would upgrade for the extra insurance.

Gl give us an update...

no reason to, i think honda can design a valve spring to support their own cams haha. and mileage isnt a concern as i bought them new from honda.

as long as i keep the stock redline i think ill be fine. was just thinking about 9k but just a thought, when i get it tuned by locash, ill let him decide lol.

I was thinking more of a later cam upgrade. Springs would already be done. But if it doesnt even make power past 8k then no need to even go to 9.

this is true, but if it does make power i wanna know if i can keep pushing it haha.

I might also just get the SkS2's and upgrade valvetrain. the hp is totally worth it.

Will i NEED portwork with these cams or will stock gsr porting suffice?

Just run ITR/CTR cams & have Joe tune it, call it a day. & yes, you can still boost with that high of compression, you just have to tune for it! I run 11.5:1 compression on stock sleeves with stock itr pistons, ls rods & 340whp of track abused fun. It's all in the tune!

really? tempting.... 91 octane pump gas?

and a weird question, but people say gsr cams have a good profile for boost, now an itr or ctr cam, would they make more power safely or something?

Also, another thing. My piston to cylinder wall clearance is 0.0005" (honda spec is .0004-.0016) I put it on the tight side so i would have room for a quick hone rebuild later down the road haha. I now realize that this clearance could be a problem with boost. I cannot seem to find a straight answer as to how much an oem piston expands under boost. Its within the stock limit, and a gsr and itr have same ptw spec so i would trust it for some itr cams, but boost is another story haha.

What do you run your clearances at?

yes on 91 pump, rc 750's with walbro 255

I run gsr cams because they are cheap, and they are not a limiting factor in my setup (the rods/pistons will be an inhibitor of making more power more than anything). ITR cams are great for boost, but they aren't "needed" to make power with boost, so save the coin for gas $ & just use your gsr cams if your going boost. Either cam will be "safe" with Joe tuning, in theory you might be able to make more power at a given boost level with ITR cams instead of GSR, but it won't be a drastic difference, up the boost 1-2psi and you'll more than overcome any shortcomings of the gsr cams.

I ran quite a bit looser clearances based on online feedback, endyne recommended specs etc. I'd ask Joe about your clearances & what he thinks about them with boost. My specs:
ring gap .012
P:W .0030

I only have like 1200 miles on this build over the past 2 years, but all miles are TRACK miles so non stop abuse...

I hate hone rebuilds, just bore it out.

how much a piston expands under boost? really that's more temperature related from my understanding, Never really worried too much about it. It's still aluminum...

ah, my problem is that im running oem internals haha. endyne is a forged piston right?

my motor basically screams N/A, but I WANT BOOOOSTTTTT :pissed:

Wth sounds tooo familiar

I agree if going with boost just use the GSR cams as they will not really limit the power with a turbo setup and in may cases stock cams are better than aftermarket cams when boosting. This is in general there are some very good turbo cams with lots of R&D behind them and yes larger NA cams can make more power when used with boost. The problem can lay with the NA cam overlap. Having a turbo creates high exhaust back pressure between the head and turbo and this back pressure can be pulled back into the combustion chamber while the cam profiles are overlapping. This basically can cause a lose in power because the exhaust gases are taking up room that air and fuel could be using to make a better burn thus more power. A stock cam will have less overlap, stock includes ITR/CTR cams as they are OE cams. A stage 1 cam has been seen to gain some power but I personally would put the money elsewhere. If going NA with the setup I would use S2T2 cams. These cams rip and with good tune are very streetable.

when I said Enyne I meant ring gap & p:w gap recommendations. I run cast replica 81.5mm ITR pistons.

Alright, thanks guys, the replies are awesome and exactly what im looking for!