[Mk2] [Turbo] Which Cams to get?

[cantfindausername]

An engine will only flow as much as the most restrictive part. Just my 2 cents.

Twin rails for the win though, if I do say so myself



and a ram horn

[salamanzer]

You must not be reading all of the information im giving you.

I have a rear mounted RMR intake manifold, I think you under estimate the amount of air the head can flow in stock form, do you have pictures of how you ported your head?

Most people ruin the flow of the head with inaccurate and inexperienced headwork, I never said headwork was unimportant, I said it was not neccesary for power levels under 600hp, proved many times on many setups.

What are the specs of your engine, 800rwhp is alot to put through the motor reguardless of how much headwork etc you have, even the 2.2 blocks are not strong enough to handle consistant amounts of hard driving at that horsepower, block girdles, sleeving them, filling them with concrete and other stuff to stop cylinder cracking and distortion just doesnt cut the mustard when the engine is that highly strung.

I dont understand how alot of people always use the airpump terminology and then stick to a 2 litre platform with a massive turbo, if getting air "through" the engine is so important then heres some more terminology - theres no replacement for displacement.


Graeme

Graeme,

The head, rev3 onwards is ok for more power than say a rev2 head, but the head IS what makes the power on a car.

Sadly, if you send your manifold to some random machinist and expect some super head work, then well its gonna be crap! If you want trick headwork and multi-cut valve heads then you need to ask a company like puma racing to do your head work!

I don't have any pictures of my headwork.... but i can tell you know its super trick ask Nathan @ century!!! I know people with standard heads at powers around 550fly (rev2) and the problem is that the head needs work else the inlet temps just go up instead of the power, then you get knock....

LOL, i agree the power levels some of us run mean its not going to be reliable, but some of us like to push the boat out and see what these little 3SGTE engines can do, if it wasnt for people like me and people in the drag circuits getting every last HP then can, then things would not progress.... ive also seen a lot of 600bhp+ fly cars appearing on this forum over the last year, i dont think many of them have standard heads....

I agree using a small 2L engine and extracting huge power from it is well crazy and that the "theres no replacement for displacement".... i could go to a V6 setup and maybe get more power, but at this moment in time I'm interested in finding out how much power can be made from a standard unsleeved 3SGTE block!

But hey the 2L evo boys are running 7s,8s, and 9s but perhaps they should give up and put in a viper engine, then again the turbo F1 blocks of old made 1500hp on a 1.5L engine.... "theres no replacement for displacement", na doesnt cut it with me!

Jason

[salamanzer]

im running 272s aparently....(so recon ats racing)
no idle problems, sounds LOVELY to..
idle is at 1400 tho, lol.
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How does it idle at stock speed, like 950rpm or whatever? 1400rpm isnt idling really is it lol

My car idles ok, but it idles really smooth at 2000rpm lol

Graeme

LOL, im running 288's my car idles at around 1250/1500, but only because i need to keep up the oil pressure up, else u can hear the cams grinding

[salamanzer]

An engine will only flow as much as the most restrictive part. Just my 2 cents.

Twin rails for the win though, if I do say so myself



and a ram horn

Nice bit of kit you have there!!!

Are you running a standard rev2 or rev3+ head on that car, or has the head been port/polished/valve enlargement?

As you say, an engine will only flow as much as the most restrictive part, and that's the HEAD....

[cantfindausername]

Its a stock Rev2 head with custom cams. The only head "work" I've had is:
Ceramic Coating applied To Combustion Chambers, Valve Faces & Piston Crowns
Lubricating coating applied To Inlet Ports, Exhaust Ports & Valve Stems

This is the flow chart for the head if anyone is interested.

[Leakie Tbar]

I've just had fitted
Hks 264 in and out
Hks pullies
Duel sprung valve springs
and ferral valves

I have ferral valves LOL and dual sprung valves also 264 in and out cams,

those ferral valves are wild

[cantfindausername]

those ferral valves are wild

haha classic!!

[salamanzer]

But going back to the original question;

Paul @ Kent Car Craft, your rev2 head will not be helping your cause when it comes to power.

If i were you id send it off to have cams and headwork for your "couple of K"

You don't need oversize valves, but an excellent port/polish and inlet flow matching will do great along side some "slightly" wilder cams.... by a respected, well known and trusted company.

Companies worth their salt will not just port/polish an inlet but polish it then sand blast it slightly as mirror surfaces (they look nice) makes the fuel stick to the inside of the ports and you lose power.

OR just go to a REV3 head if you can get it to fit into your budget.

Jason

[oBladeo]

i always forget what there called lol

Ferrea Valves and Supertech Valve Springs Retainers

that better? lol

[^Trickster^]

to say that displacement doesnt matter is a bit contradictary to everything you have said.

1.5litre formula one engines last one race lol, put in in an endurance race with a v8, v10, v12 NA supercar and see which one lasts the longest, I know where my money would be,

I dont think the head is the most restrictive part, the most restrictive is dependant on your setup, fit a ct26 to your motor and no ammount of headwork will sort that out

I dont think there is anything left to prove with the 3sgte engine. I could go in my garage now and build a motor with block girdles, solid liners, filled block, 1 million cc injectors and a turbo so big i cant fit the engine lid on anymore, it might make a hell of a number and maybe pull some good drag times but how far do you want to take it.

I built my own car..... from a shell, the only thing I have not done is machined the block and head.

I have put a car together that i can start on a morning, and drive all the time, it has made over 400hp since its first dyno at 500miles and has now done 13k miles of hard reliable driving and now its going to make more power and still drive everyday. Now thats more important to me than a big figure.

Ants car is a awesome piece of kit, because of the attention to detail he has put into it, i have never said theres anything actually wrong with tubular manifolds or dual rails, I said I dont like them. Personal preference is what made my car what it is.

Jim: Try turning the idle down on your commander and see what it stays smooth at, anything under 1350 for me is a bit rough as I have solid mounts on the motor.

Graeme

[salamanzer]

Its a stock Rev2 head with custom cams. The only head "work" I've had is:
Ceramic Coating applied To Combustion Chambers, Valve Faces & Piston Crowns
Lubricating coating applied To Inlet Ports, Exhaust Ports & Valve Stems

This is the flow chart for the head if anyone is interested.

Nice graph, your cams (if you dont mind sharing the info), whats the duration and lift on them?

Also do you have the before and after images of the CFM against inch's lift?

Looking at that graph at max inch's lift the head flows just under 250cfm, when you base that against my turbo which pushes 1300cfm then maybe u see why to me good headwork is required

Jason

[^Trickster^]

But going back to the original question;

Paul @ Kent Car Craft, your rev2 head will not be helping your cause when it comes to power.

If i were you id send it off to have cams and headwork for your "couple of K"

You don't need oversize valves, but an excellent port/polish and inlet flow matching will do great along side some "slightly" wilder cams.... by a respected, well known and trusted company.

Companies worth their salt will not just port/polish an inlet but polish it then sand blast it slightly as mirror surfaces (they look nice) makes the fuel stick to the inside of the ports and you lose power.

OR just go to a REV3 head if you can get it to fit into your budget.

Jason

This sounds a bit off to me..... theres no way on this planet 2.5k of headwork is going to make more power than a rmr or similar manifold and a set of cams which will be half the cost.

and saying swap in a rev 3 head, id love to pull an engine apart to fit a rev 3 head, im running a rev 1 head and watch that baby flow 550hp next week!

[jimGTS]

Graeme
no real point, lol, have realised that of course higher idle speed will mean a smoother idle. doh.
so putting it less than 1300 is pointless, as it doesnt bother me where it idles crap, i like it idling at 1300-1400, lol, sounds cool.

[salamanzer]

to say that displacement doesnt matter is a bit contradictary to everything you have said.

1.5litre formula one engines last one race lol, put in in an endurance race with a v8, v10, v12 NA supercar and see which one lasts the longest, I know where my money would be,

I dont think the head is the most restrictive part, the most restrictive is dependant on your setup, fit a ct26 to your motor and no ammount of headwork will sort that out

I dont think there is anything left to prove with the 3sgte engine. I could go in my garage now and build a motor with block girdles, solid liners, filled block, 1 million cc injectors and a turbo so big i cant fit the engine lid on anymore, it might make a hell of a number and maybe pull some good drag times but how far do you want to take it.

I built my own car..... from a shell, the only thing I have not done is machined the block and head.

I have put a car together that i can start on a morning, and drive all the time, it has made over 400hp since its first dyno at 500miles and has now done 13k miles of hard reliable driving and now its going to make more power and still drive everyday. Now thats more important to me than a big figure.

Ants car is a awesome piece of kit, because of the attention to detail he has put into it, i have never said theres anything actually wrong with tubular manifolds or dual rails, I said I dont like them. Personal preference is what made my car what it is.

Jim: Try turning the idle down on your commander and see what it stays smooth at, anything under 1350 for me is a bit rough as I have solid mounts on the motor.

Graeme

I said that " i could go to a V6 setup and maybe get more power"!

An F1 car still had to do 50 laps or so, this is no 24 hour race but.... if they wanted more reliability they would de-tune it.

Hey but its horses for courses, my goals are different to you.... i want to make outright power for 1/4 mile, i don't to potter to sainsburys to get my shopping.

A CT26 is labeled at a max of 35lbs/min so thats 503cfm....

Jason

[cantfindausername]

I'm holding the exact cam specs for the time being till I get the car back. Rogue use the manufactureer (CATCAMS) in all their builds too.

The rough specs are:
Inlet 11.25mm lift/258deg
Exh. 10mm lift/236deg

They have very aggressive ramps.

The max lift was 0.45" lift, and yeah max flow was 245 CFM, but that is only 1 port no? I'm not entirely sure how these things are worked out. Just thought it be interesting for people to see some of the things people are talking about.

I'm definately a believer in head work giving results, but its horses for courses, and for low - mid power, I believe the stock head is fine.

[^Trickster^]

Salamanzer: Make sure you post results, ill be keeping my eyes open for them between driving to and from sainsburys.

[salamanzer]

Yeah that will be for 1 port.

It depends, the GT3071 is 576cfm of air flow as its a 40lbs/min wheel if i remember.

But you do have a LOT of lift there, much more than a standard off the shelf cam.... which are around the 10.5 mark.... but its good to see you haven't gone too mad on the duration

So 11.25 is .45" lift
So a 10.5 is .41" lift

Looking at the chart that's about 230cfm ish.... at peak lift, based on your head and cams

A GT3071 would struggle I would think on a standard head and cam, you have to base the maximum flow based on the area under the graph, taking into account the air has expanded when it tries to flow back out the exhaust port, and the turbo and will slow the entrance of new fresh compressed air.

There is a formula to work it out exactly, i will dig it out, this shows how much a head can flow in terms of CFM based on port size and valve lift.

Jason

[Leakie Tbar]

Grrrrr gggrgrgrgrgr


I'm Bored

[salamanzer]

LOL

[salamanzer]

Salamanzer: Make sure you post results, ill be keeping my eyes open for them between driving to and from sainsburys.

Will do mate