[Mk2] [Turbo] Which Cams to get?

[Andy F]

Just get a rev3 head cams and manifolds and bolt it to your rev2 block
using a stock rev3 gasket, no isuses what so ever.
i have been running 2 bar boost with a gt3076 for ages, no idea what power its running but 11.5 @ 124mph consistant is pretty good.
My car drives like a stock mr2 but mega fast and thats what we all want
when we start modding em!!!
good mapping helps too

What spec is the rest of the engine?

Nothing special, CP pistons, tilton twin carbon clutch, HKS fuel rail and FPR with 1000s Group A exhaust manifold every thing else is stock even the head bolts!
If you/Paul want a fast street car forget all the crap about buying bigger cams pullys and head work its not needed, its ok if your chasing 9 sec quarters, but 95% of us on here would be happy with 11.5 and a car that will last for years not just a few runs.......
Rant over

[^Trickster^]

Andy F: +1

[greeny]

Hks 272's + 1mm o/s valves here, no porting

Didn't Dino (mr2mania) have tests done years ago that showed that the rev1 head flowed better/more than the rev3 head in stock form iirc?

[Andy F]

I think your right Michael, BUT the cams aint as good?

[^Trickster^]

Im not sure about Dino, but the I think ChrisK did a flow test and this was also the case, I also believe that the rev1/2 are better for headwork too because of the way they are cast, you can port them larger, however im not sure on how true that is.

Graeme

[greeny]

I think your right Michael, BUT the cams aint as good?

Yeah i cant remember for sure.

[cantfindausername]

Stock 2nd gen motor: (intake and exhaust)

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

Stock 3rd gen motor INTAKE:

Advertised duration 240 degrees

4 degrees more duration, .5mm more lift than the 2nd gen

Stock 3rd gen motor EXHAUST:

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

Got plenty other cam specs here too if people want them.

[Century Motorsport]

Hi All

After some advice from you guys.

Current engine mods I have at present:

GT3071r Turbo
Link G3
Walbro 255 Fuel Pump
870cc Injectors with side feed fuel rail (Wolfkatz)
(for full mods check my garage)

Now the best time I could managed at the Pod was 13.1, which was disappointing to say the least, and then when I had it dyno'd at TDi it was only putting out around 350fwhp. I was expecting around 400fwhp. This was at 1.8bar too!! Although it did peak to 1.9bar then drop off, it's quite heavily fueling on boost, but the head just cannot flow enough air.

Now, the obvious retriction here is my head, it is totally stock. I did have it all lined up for some very extensive headwork, but then thought do I really want to be putting another £4k into this car.... the answer is now NO!

I do however want to put some cams and pulleys in RIGHT NOW! Could the pros please check out my set-up and suggest which cams would be the best to go for? I've been thinking HKS pulleys and HKS 264 low lifts to retain torque. I do not want a car that idles all horrible and lumpy like I have seen with 272s. I see that people also combine 264/272s. I'm going to bite the bullet and spend the £600 that I need to.

Cheers

264/264 is your best option. I recently built a motor for a customer with the same kind of specs with the 264 combo and the power was 430FWHP @ 1.8 bar IIRC - stock Rev 2 manifold + TB.

Trickster - The std Rev 3 manifold + TB are good for 500hp, i did it before I went with the KU unit.

Nathan

[^Trickster^]

Nathan: I am still using the stock rev 3 throttle body on the RMR, the stock manifolds do make power, but dont you find larger plenums give a much nicer curve and delivery?

Congrats on the latest results

Graeme

[Whippett]

264/264 is your best option. I recently built a motor for a customer with the same kind of specs with the 264 combo and the power was 430FWHP @ 1.8 bar IIRC - stock Rev 2 manifold + TB.

Trickster - The std Rev 3 manifold + TB are good for 500hp, i did it before I went with the KU unit.

Nathan

Cheers Nathan (and everyone else!) I think after the advice here and some from others I will go with the 264/264 option. While I'm there I may as well look at a manifold before getting it re-mapped.

[Andy F]

Paul, ...if your only making 350hp at 1.8/9 bar on a gt30, theres must be a problem mate, and its not the head or which cams your using.

i wouldnt start UPGRADING until the basics are working as they should.!
What was your terminal speed BTW

[Whippett]

Paul, ...if your only making 350hp at 1.8/9 bar on a gt30, theres must be a problem mate, and its not the head or which cams your using.

i wouldnt start UPGRADING until the basics are working as they should.!
What was your terminal speed BTW

This is what I'm thinking! Although the car drives fine and seems to have no problems. It is fuelling a lot on boost (as low as 10:1) which was a precaution and is probably causing a power loss at present, but it was starting to get compressor surge at 1.8bar during mapping.

Terminal speed was 108mph

[greeny]

Paul, ...if your only making 350hp at 1.8/9 bar on a gt30, theres must be a problem mate, and its not the head or which cams your using.

i wouldnt start UPGRADING until the basics are working as they should.!
What was your terminal speed BTW

This is what I'm thinking! Although the car drives fine and seems to have no problems. It is fuelling a lot on boost (as low as 10:1) which was a precaution and is probably causing a power loss at present, but it was starting to get compressor surge at 1.8bar during mapping.

Terminal speed was 108mph

Id say theres definately something a miss then as i was hitting 105terminals with a ct26, and my bro in his stock rev3 was hitting 107mph.

As said theres a car in america hitting 9sec quarters on the stock inlet manifold/throttle body so id say that the inlet mani def isnt your problem!

[Ryan.g]

Hi Paul

As i said when mapping chap, a set of 264, 264 cams will finish it off nicely. I could see when mapping the car on the fueling graph that the engine was not not accepting any more air flow after we got past 1.4bar and is why i suggested bringing to the dyno to prove this by lowering the boost to 1.4bar and then turning up to 1.8bar and expecting no gain maybe even a loss of power because of where the fueling will be going richer and the charge temps being higher with the added pressure.

On the current setup the engine just cant digest all the air flow from the gt3071r due to VE of the engine with those stock rev2 cams. The inlet espically.

Another setup i did about 2 month ago which nathan is talking about is exactly the same spec as yours and made over 80bhp just by letting it breathe more.

TBH i would say those figures are about right with the stock cams still installed. Doesn't matter if you fit a t88 to it... the cams will still restrict the power.

It also needs finishing of on the dyno as i think your wideband is out as the vems units do have issues if there are some ground offsets.

Ryan

[Andy F]

(4 degrees more duration, .5mm more lift than the 2nd gen )
So your saying this amount of difference is holding him back from running
18 bar + of boost??......

[Ryan.g]

(4 degrees more duration, .5mm more lift than the 2nd gen )
So your saying this amount of difference is holding him back from running
18 bar + of boost??......

Yes 18bar of boost on those profile would be hard.....

On Pauls motor and other rev1-2 with stock cams and bigger blowers i have found that anything over 18psi and the engine just requires the same amount of pulsewidth in fueling pretty much when increasing the boost. Obviously with the rising rate reg installed it does increase the pressure in the rail so that provides more fuel but still the pulse width required should increase with pressure. If it is not then you know normally you have a restriction on the intake side of things.

On rev3's it is different they seem to hope well with the added pressure and require more pulse width. On some rev3 engine with stock cams etc i have achieved 400+ but never on a rev1-2.

Even when installing a rev3 inlet into a rev1-2 they still dont seem to flow as good as the rev3 head as stock.

Ryan

[Whippett]

(4 degrees more duration, .5mm more lift than the 2nd gen )
So your saying this amount of difference is holding him back from running
18 bar + of boost??......

18bar of boost lol

A couple of people have mentioned starting off with a rev3 head but I'm pretty sure they will not fit a rev2 block?

So Ryan, should I get some low or high lifts? Also, would you recommend getting an aftermarket inlet manifold at the same time?

[Ryan.g]

(4 degrees more duration, .5mm more lift than the 2nd gen )
So your saying this amount of difference is holding him back from running
18 bar + of boost??......

18bar of boost lol

A couple of people have mentioned starting off with a rev3 head but I'm pretty sure they will not fit a rev2 block?

So Ryan, should I get some low or high lifts? Also, would you recommend getting an aftermarket inlet manifold at the same time?

I would stick the with the stock intake for time being and go with the low lift units.

Not even sure the high ones fit a rev2 head...

[Andy F]

Paul. the rev3 head drops straight on the rev1/2 block no problems.
This would be the easiest and cheapest option, you must be able to pick up a rev3 head inlet and exhaust manifold for 2/300 quid then just get a rev3 HG and away you go!
Ryan, interesting stuff about the early cams, do you find you have to start pulling ignition higher up the revs?

[Ryan.g]

Paul. the rev3 head drops straight on the rev1/2 block no problems.
This would be the easiest and cheapest option, you must be able to pick up a rev3 head inlet and exhaust manifold for 2/300 quid then just get a rev3 HG and away you go!
Ryan, interesting stuff about the early cams, do you find you have to start pulling ignition higher up the revs?

See im not sure if its just the cams as there are a few differences between the heads but even on cars that have fitted the rev3 intake manifold as well have been the same so its not the manifold either that a restriction i would say either.

As torque drops off and the power levels off you can add more timing but found it doesn't make much differences. Only a couple of HP tho

Ryan