camshaft selection

[BluntyR5GTT]

hi guys im at some point going to be upgrading the cam in my engine and am wondering what will be the best combo for the following set up

hybrid t2/t25 with .63 housing running 16-18psi
all carb sorted and fuelling set up
full downpipe back exhaust system and bored out turbo elbow

i will also be getting the head fully ported etc if i uprate the cam

im wanting the most drivable cam to suit really and not after peak figures as am not someone who goes figure chasing tbh lol.

the cams iv been looking at are as follows

ktec fast road cam
piper 270 cam
piper 285
cat cams 5500315

they are the 4 am looking at obviously 2 are milder than the other 2 but i dont mind milder if it goes with the set up better than a high lift cam

this is something that i hope to get done before national day this year so any help and advice would be really appreciated

[TrixNFlix]

Ever considered just running the standard head and cam?

[BluntyR5GTT]

of course but if a decent improvement can be made to compliment the turbo upgrade etc then ill be more than happy to get it done

[TrixNFlix]

Yeah but at those boost levels, I don't think it's worth it. Just my opinion though, and as always, it's your car and money.

[BluntyR5GTT]

right now thats more of an answer there as im not really going go for massive boost so i was just seeing if any of them cams are suited for 16-18psi on the stated turbo

[TrixNFlix]

The standard cam with that turbo, at that boost level will be great. :agree:

[BluntyR5GTT]

spot on then if thats the case then all is good :)

[Mart]

And it was fairly well documented in your other thread that headwork isn't a neccessity either, but aii, it's your car, your money...

[BluntyR5GTT]

nah the headwork would only of been done if i was uprating the cam tbh should of stated that in original post ill edit that now

[Mart]

Yeah, but...Ok :coffee:

[BluntyR5GTT]

cheers for the input anyway guys only reason i asked about the uprating of the camshaft is because i did it in my old rs turbo when i had the boost etc turned up in that and it worked a treat it was a piper 285t cam iirc, i know all cars are diff tho and by the looks of it the 5 gt turbo only responds to a cam upgrade when running big boost ?

[jonnyshaw49]

what would a full t25 be like on a standard cam??? would it be too laggy as it wont kick in untill 3.5k , anyone running a t25 on standard cam?

[BluntyR5GTT]

from what i can gather it will depend on your boost etc unless with running a full t25 an uprated cam works well ?

[jonnyshaw49]

what about if your running max boost your engine will take with a t25, what psi is ok with full t25 on a c1j with headwork and double intercooler and all the cooling,full silicone hoses, k and n filter, double alloy rad and oil cooler????im 90 percent sure my car has a mild cam of some sort as the car was giving out good power standardish and the valve springs were black not red, but im just wondering incase it is a standard cam, as im ordering a full t25 in the next week or two off adam l thanks

[rs250nut]

Standard cam matched mainfold and big turbo made over 210bhp. I know that set up is not ideal but I was sold the bottom end with the seller stating it had a hot cam in it. Oh well opens the window for more power:smokin:

[jonnyshaw49]

i have matched manifold and also bored out turbo elbow, two of my turbos have bidders now so just one more to go and i can order a brand spanking full t25, cant wait!!!!!!

[rs250nut]

what about if your running max boost your engine will take with a t25, what psi is ok with full t25 on a c1j with headwork and double intercooler and all the cooling,full silicone hoses, k and n filter, double alloy rad and oil cooler????im 90 percent sure my car has a mild cam of some sort as the car was giving out good power standardish and the valve springs were black not red, but im just wondering incase it is a standard cam, as im ordering a full t25 in the next week or two off adam l thanks

Most of the crap listed above is not really needed, silicone hoses wont make you go any faster as said by mart above for the tenth time the headwork wont do a great deal standard rad is good enough so is the oil cooler maybe unless your thrashing it to 8000rpm round a track for an hour.

[jonnyshaw49]

no i know but silicone boost hoses are better for the boost and headwork helps with fueling to the engine, just as boring a venturi would, i was asking what would a full t25 be like on a standard cam? and what power would be likelyat max psi the engine will take with the mods i have??

[Mart]

no i know but silicone boost hoses are better for the boost

o.e's are more than upto the job.


headwork helps with fueling to the engine

:dearme: I give up!



i was asking what would a full t25 be like on a standard cam? and what power would be likelyat max psi the engine will take with the mods i have??

Define 'full T25' - Inducer/exducer diameters? a/r's?

[jonnyshaw49]

not sure on the a/rs yet but adam l who is going to make the turbo said If i want something for £500 he can do a T25 with a machined out T2 exhaust housing for around 500 delivered. That will do over 200bhp but not sure if he means with a bigger cam or standard. im not too clued up on turbos so just asking

[Mart]

A cam isn't going to make that much difference in the grand scheme of things, not at the level of tune you're at at the moment.

You only need to start tickling with cams when you want the powerband shifted upwards; ie, to work hand in hand with a larger turbo whose spool-up characteristics will be naturally higher in the rev-range.

It's pointless fitting a hot cam with an o.e or similar sized turbo, as why would you want a higher powerband with a turbo that's spooling up low down the rev-range/running out of puff as you're nearing the redline?

And regarding power output, given an o.e T2 can squeeze 170/180hp, I'm guessing one of Adam's 'T25' conversion turbos should net you 200hp easily.

[jonnyshaw49]

thanks for the reply that explains alot, ive just heard so many people on here go on about t25's with the 285, so at that rpm does a t25 run out of puff, i may aswell stick with what i got for the time being at get a nice 200 bhp

[Markey Mark (BD)]

headwork helps with fueling to the engine, just as boring a venturi would,

Totally disagree with you there on the venturi bit mate, large venturi carbs are worse thats standard ones

[BluntyR5GTT]

this is something iv heard alot since signing up on here all these group a carbs are no good and its best to mod the 2nd stage is that right ?

[Markey Mark (BD)]

this is something iv heard alot since signing up on here all these group a carbs are no good and its best to mod the 2nd stage is that right ?

Yep! :agree:

The so called 'grp A' carbs tuners sold are all mainly large venturied carbs with larger main jets, smaller air correcter and some had larger 1st stage, i:e overgueled like hell always unless you put yor foot down then it run lean high up the revs at high boost

[BluntyR5GTT]

Yep! :agree:

The so called 'grp A' carbs tuners sold are all mainly large venturied carbs with larger main jets, smaller air correcter and some had larger 1st stage, i:e overgueled like hell always unless you put yor foot down then it run lean high up the revs at high boost

this is what iv started to learn since coming on here makes you wonder how they would still sell them as they obviously dont work right. iv got a 130 main on mine running 16psi i understand that when i upgrade to the hybrid t2/t25 with .63 housing this should still be fine as ill be running it at 16 maybe 18psi max

[Markey Mark (BD)]

this is what iv started to learn since coming on here makes you wonder how they would still sell them as they obviously dont work right. iv got a 130 main on mine running 16psi i understand that when i upgrade to the hybrid t2/t25 with .63 housing this should still be fine as ill be running it at 16 maybe 18psi max

I thought with the set up you got now a 1.2mm main jet would have been enough.

It's not really the main jet you souly need to worry about, its the 2nd stage enrichment thats what adds the extra fuel when boost is applied.
I wouldn't be suprised if you have to adjust the carb again once you fit the new turbo, even though its the same boost is it the same amount of air going in? Remember bigger turbo's flow more air

[BluntyR5GTT]

i actually thought that it may need tweaking and maybe the 130 main may suit the bigger turbo better ? i understand adding the 0.90 air corrector wont do it any good as well.

[TrixNFlix]

I thought with the set up you got now a 1.2mm main jet would have been enough.

It's not really the main jet you souly need to worry about, its the 2nd stage enrichment thats what adds the extra fuel when boost is applied.
I wouldn't be suprised if you have to adjust the carb again once you fit the new turbo, even though its the same boost is it the same amount of air going in? Remember bigger turbo's flow more air

Very well explained.:agree:

[Markey Mark (BD)]

i actually thought that it may need tweaking and maybe the 130 main may suit the bigger turbo better ? i understand adding the 0.90 air corrector wont do it any good as well.

Bigger turbo's don't neccessarely mean bigger main jets, also fitting a smaller acc isn't a bad thing but you only do it if its needed thats why its so important to stick an AFR on the car to see whats its doing and then adjusted prpoerly.

[BluntyR5GTT]

cheers pal it will have a wideband on there to see whats going on then get it adjusted accordingly :)

[Markey Mark (BD)]

cheers pal it will have a wideband on there to see whats going on then get it adjusted accordingly :)

Ok cool mate;)

[BluntyR5GTT]

appreciate the help as im new to the gt turbo tuning scene

[Markey Mark (BD)]

appreciate the help as im new to the gt turbo tuning scene

You sticking your car on the rollers on this rolling road day?

[BluntyR5GTT]

bloody defo mate that was how the day idea started lol i was going take mine so i thought why not organise a rr day :)

[BluntyR5GTT]

want get this oil leak fixed 1st tho have renewed the sump, seals and gaskets along with new sandwich plate still no joy checked the sensors it was none of them they were spot on

[Markey Mark (BD)]

bloody defo mate that was how the day idea started lol i was going take mine so i thought why not organise a rr day :)

Cool cool, what could do is see what the AFR's are like and advise what you may need to do when you upgrade later on.

[BluntyR5GTT]

sounds like a plan fella :agree:

[jonnyshaw49]

are uprated springs needed with the piper 270??? what is the highest lift cam without replacing springs?????

[Markey Mark (BD)]

are uprated springs needed with the piper 270??? what is the highest lift cam without replacing springs?????

The stronger springs aren't needed for the 270 but personally i'd would fit them.

[jonnyshaw49]

what is the highest lift cam without them?? can you refit springs without takin head off??

[car.crash]

what is the highest lift cam without them?? can you refit springs without takin head off??

it is possible to fit springs with the head on, but i remember it being a ball ache.

[Markey Mark (BD)]

what is the highest lift cam without them?? can you refit springs without takin head off??

I can't remember how much the valve spring will go down untill the coils touch each other.
Also the reason for fitting stronger valve springs is not just about the lift, its about how harsh the valve is moved so by fitting stronger ones you control the movement of the valve more hoping to eliminate valve bounce. Depending on the design of the cam it will determine weather you'll need sronger valve springs or not.

If you got the tool to pressurise the cylinder to hold the valve up while you take the spring off then yes, if not you'll have to have head off.

[jonnyshaw49]

can one person wind the bottom end over whilst one undoes the valve?? or do you need the tool?

[Markey Mark (BD)]

can one person wind the bottom end over whilst one undoes the valve?? or do you need the tool?

No don't even try that, you'll end up bending the valve or beaking something.

You'll need a valve spring compression tool to remove the valves from the head with the head off, easiest way to do it.

[jonnyshaw49]

ok wont try that, im gonna take the rocker off sometime to repaint it as the chrome has all come off so will take a pic of the springs to put on here, but like you say might have uprated springs but standard cam, so i will try and get hold of one of them dials and plungers mto measure it. i have 2 spare blocks in my barn if i take the cams out can anyone tell by the pic what cam it is??? as i might already have an uprated cam between the 3 so wont have to buy one. thanks

[BluntyR5GTT]

after speaking to a few people am quite tempted when the time comes to go for a 270 cam at 18psi boost on the t2/t25 .63 housing

[Markey Mark (BD)]

ok wont try that, im gonna take the rocker off sometime to repaint it as the chrome has all come off so will take a pic of the springs to put on here, but like you say might have uprated springs but standard cam, so i will try and get hold of one of them dials and plungers mto measure it. i have 2 spare blocks in my barn if i take the cams out can anyone tell by the pic what cam it is??? as i might already have an uprated cam between the 3 so wont have to buy one. thanks

If you look on the end of the cam it will have some numbers or letters stamped into it, have alook at what your spare ones say and let us know

[jonnyshaw49]

nice 1 i will let you know when i route them out thanks,the 270 with t2/t25 sounds good mate, have you got headwork etc??what power will it be pushing out???

[Markey Mark (BD)]

Ok mate see what they say on them

[BluntyR5GTT]

nice 1 i will let you know when i route them out thanks,the 270 with t2/t25 sounds good mate, have you got headwork etc??what power will it be pushing out???


no not got headwork done and tbh av been put off getting it done by quite a few people on here, unsure on power really as long as its fun and good to drive i dont mind lol thnink anything over 180bhp in a gt turbo is plenty really

[jonnyshaw49]

true, why have you been put off by headwork on here??? what are the reasons??i thought it was good for turbo'd cars thanks

[BluntyR5GTT]

people say its not really worth it as the standard head flows enough for 200+bhp iirc, but iv always had the heads done on my car and been tested on a flow bench and the cfm for inlet and exhaust always been miles better.

[stevo clio]

hope you dont mind me jumping in on this thread but im just starting to look at turbo upgrade and cam upgrade also. But after reading through this thread i think i might have been thinking along the wrong lines (as in too big) Was thinking of the following give or take-
Piper 300 cam with uprated springs
min T28 or T3
obviously carb work (not a group A!) but not sure what jets i would need
also what other work would i need in the way of the block (pistons rods etc?)
lightened and ballenced flywheel?

Its ONLY to be used for 1/4 miles so as long as my power is somewhere between 4500- 7000rpm hopefully and would like to see the high side of 250bhp

like i said i think i have been looking a bit too high so i don't need the next 10 replys or so to be just slaging comments please :)

thanks

[BluntyR5GTT]

christ on a turbo and cam that big you can go way past 7k fella

[stevo clio]

i have been offered the t3 for free :) thats why i was thinking of using it

[Andrew Cooke]

i have been offered the t3 for free :) thats why i was thinking of using it

The right T3 is probably a good choice for what you want to do, but it's far from easy to fit one.

I wouldn't use a Piper 300, too much overlap for high boost

[Scoff]

yes, I can vouch for the BP300 not working with much more than 20lb of boost. BP285 with a vernier is what you want for now. It takes a lot of effort to improve on that.

[stevo clio]

thanks for the replys, but what you think about the block/ pistons. can remember some people saying just stick with the standard parts?

[BluntyR5GTT]

think i read pistons are good for 270bhp and rods 400+ this might be wrong but iv heard it a few times now

[Scoff]

think i read pistons are good for 270bhp and rods 400+ this might be wrong but iv heard it a few times now

cripes, there arn't enough people with 400hp in a C1J to validate that statement. maybe only the one person, gianni santi. I did not ask him what rods he had, most likely not standard.

but for the 200+ hp goal the standard parts will be adequate. pistons being more prone to failure than the rods, so if anything, buy some reputable pistons. ofcourse, don't buy them unless you are 100% confident of your tuning ability. there's nothing more gut wrenching then melting a brand new £600 set of pistons because you got the jetting, or timing slightly wrong ;)

[BluntyR5GTT]

lol as i said i actually dont know if thats the truth its just something id heard a couple times, personally i wouldnt trust standard rods,pistons over 220bhp tbh

[Rob@Backyardracing]

Im still convinced that you can get away with a cast piston DONE RIGHT, Ok i aint calling forged pistons as they are good... But take our honda, we run chinese copys of the vitara OE pistons, so cheap as chips £50 brand new.. They are cast and nothing fancy, just have a larger tapper, and with an increased Piston to wall to match your tune you should find it would work well.. Ive seen peeps over 500hp on casts... Why doesnt anyone try this with a renault pistons?

[Scoff]

lol as i said i actually dont know if thats the truth its just something id heard a couple times, personally i wouldnt trust standard rods,pistons over 220bhp tbh

thats probably quite sensible for the pistons atleast. the rods are pretty bullet proof, although I've seen some bannana shaped ones that came out of stuart clarkes engine. everything has it's limits :)

[Sparkie]

james willday did ages ago at a EP rolling road days. his car was rattling like a good'un until it got hot.

[Rob@Backyardracing]

james willday did ages ago at a EP rolling road days. his car was rattling like a good'un until it got hot.

Interesting.... plus if your to loose that aint good either, where will the heat go.... I thought Ian just fitted old worn pistons from what he told me years back? never said he machined them in anyway? Prob was down to the tune for the fail....:)

[Scoff]

Interesting.... plus if your to loose that aint good either, where will the heat go.... I thought Ian just fitted old worn pistons from what he told me years back? never said he machined them in anyway? Prob was down to the tune for the fail....:)

james had had those steel liners honed more times than I know, infact I remember talking to ian about it in his workshop one day.

[Sparkie]

yeah, funnily enough i asked willday about them too. he just said he had them honed again, and again and again...

but then again, he was well know for blowing his car up.

[Markey Mark (BD)]

yeah, funnily enough i asked willday about them too. he just said he had them honed again, and again and again...

but then again, he was well know for blowing his car up.

I can remember seeing his 5 being rebuilt numerous times, think in one year we counted 18 pistons!
Yep those liners got some honing

[sphinX]

yes, I can vouch for the BP300 not working with much more than 20lb of boost. BP285 with a vernier is what you want for now. It takes a lot of effort to improve on that.

Scoff, atm I only have the Cam but not the pulley.... is it a sound investment or not much gain?

[Scoff]

Scoff, atm I only have the Cam but not the pulley.... is it a sound investment or not much gain?

that depends entirely on how accurately piper gound that cam. from experience the answer is "not very" most of the time. you should check it's timing in the usual way with a DTI gauge and protractor wheel on the crank. If it times up OK then you don't need the pulley.