[Mk2] [Turbo] Rev2 to Rev3 Head Conversion *NOW MAPPED*

[Whippett]

We are soon to be completing our first rev2 to rev3 head conversion so thought I'd tell you all about it.

Firstly... in hindsight, I should have just got an entire rev3 engine a year ago and forged that when I had mine built, seen as I got a new rev2 block anyway!

Now, I am no mechanic, I just deal with the business side of things, but I have a fair knowledge and thought aside from a few differences the conversion would be pretty simple... how wrong I was!

I firstly obtained a rev3 head, throttle body and inlet manifold. I didn't even give the exhaust manifold a thought at the time.

I have had to purchase the following to make it fit:

Rev3 exhaust manifold
various rev3 gaskets
Various brackets and pipes
New injector seals (the rev3 ones are much bigger than the rev2)
Rev3 fuel rail as my overpriced Wolfkatz item is now redundant!
Water swirl pot

The small differences between the 2 heads are vast! The exhaust manifold is different in that the turbo now sits further towards the air-filter and my already modified Nur Spec flexi now is too short and needs modifying back to it's original state.

The screamer pipe now hits the down pipe (?!) so had been modified slightly. FYI we originally used the rev3 downpipe from the Berk GT3071r kit as it was a better fit than the rev2 item.

There is also an extra oil breather from the rocker cover to the inlet manifold which the rev2 does not have. The oil breather port for the stock rev3 catch can is a lot bigger than my catch can so I am modifying the catch can port to suit.

There is a bracket which secures some water pipes to the inlet manifold which is different. All the points where the hard water pipes secure to the head are different. We had to cut one off and modify another.

The base of the large water swirl pot is also different. We had to drill out a hole to fit a water temp sensor also.

The engine hanger over the cam-belt is also totally different.

All these little fiddly bits you just cannot prepare for, a rev3 donor engine to hand would have been great, but GTS Chris has been most helpful and had in stock EVERYTHING I have needed and the 3 orders I placed with him in the last fortnight were with me within 48 hours.

The original fuel rail he sent had a hairline crack in, Chris replaced this promptly at no extra charge.

TBH, I wouldn't want to do this again and would thoroughly recommend just changing the whole engine, even though the Rev2 block is rumoured to be stronger. (my last one cracked!)

Any thoughts are welcome

[bolton]

i thought bout doing this but is there much gain over the rev2 head?? im after 400bhp!!

[greeny]

Why the change?

[Whippett]

I just wanted to maximise airflow. I know there are plenty of guys making big power on rev2 heads, but I had the opportunity to buy the set-up cheap so went for it.

I wanted to uprate the cams so might as well change the head at the same time.

Thankfully we think we've found some tiny boost leaks, so this may be the cause of my lack of power over 1.4 bar, this way when I get it back it'll probably go like a rocket, not that it was slow before! We've also got a Smoke-Pro tester now so will be able to ensure there are no leaks.

i thought bout doing this but is there much gain over the rev2 head?? im after 400bhp!!

I'll let you know when it's running!

[chron]

thought about doing this, but it seems it isnt as straighforward as i thought! ah well

[Whippett]

I now just need 3 parts to finish the job

The breather pipe from the rocker cover to the inlet manifold WITH the rocker cover fitting (marked on the left of the photo)

The coupling from the throttle body to the induction pipe WITH the bracket for the throttle cable (marked in the centre of the photo)

A mounting bracket that is found underneath the throttle body; 2 bolts pass through it to mount the TB to the cylinder head. It looks like a small pair of binoculars!



Unfortunately Chris hasn't got these that he can split from a Rev3 lump, so if anyone has them please let me know!

[Whippett]

Chaps, will I be Ok just putting a breather filter on the breather port and blocking off the pipe on the manifold?

I believe the pipe that should be there has a check valve in it. Why is this extra breather on the rev3 and not the rev2?

The breather that goes to the stock catch can i've got going to my aftermarket catch can.

[Whippett]

Got the car running today

My god does it sound mean

Spent most of the day trying to find out why the starter motor continually turned over when you put the key to accessory 2 poisition, after spending hours pulling the dash apart, some internet searching revealed it to be an earth not connected to the inlet manifold!! lol

Anyways, other little things that were not compatible:

Neither the rev2 or the rev3 throttle cable bracket off the throttle trumpet worked well, so we had to modify the way the rev3 item was mounted to get the cable to sit at the right length.

Slighty downsizing the throttle trumpet by about 3mm to fit the silicone hose on - we decided this was the easiest and cheapest route.

The car now will not idle unaided (no suprise there though!) so got to get my laptop plugged into the G3 and adjust the master fuelling and idle, ready for remapping by Ryan.

[lockys96]

what happened to the wolfkatz rail mate?

[Whippett]

Nothing mate, I'm going to put it up for sale soon along with all the other bits I no longer need.

Are you interested in it?

[Benmoore999]

Hi Paul,

Hope you are well.

you finally got the Nur spec on you car then...

The breather you spoke about on the cam cover. I ended up running a pipe between that and my aftermarket catch tank seemed to work ok. I blocked up the inlet manifold end.

HTH

Ben

[Whippett]

Hi Ben

How's it going? Did you make it to the Nurburgring?

Yeah the Nur Spec went on last year, problem is I haven't really used the car much, it's always seems to be broken or having something done to it!

Once it's ready next week I fully intend to get full use out of it this summer.

I'm going to run both breathers to my catch can and block of the oil drain on the head and the inlet manifold pipe, I just wanted to get it to standard spec first so I don't do a rush job on making it look pretty!

[Benmoore999]

I sure did was a very enjoyable week. Not going this year but will be back next year. I ended up selling my MR2 to some guy from Holland. It sounds like you have had your hands full with your project... My new car is in bits across the garage floor lol. I think they spend more time in bits than they do being driven

[Whippett]

I would like anyone's suggestions on how I can best tackle high air charge temps. My car was mapped today by Ryan down at Surrey Rolling Road and the intercooler suffered heat-sink. We quite quickly were seeing temps of 50'degrees, the mapping was then aborted at 1.4 bar as they were climbing to 80'degrees Now the IC design relies on movement but on the dyno it suffered, however I would like to make it a lot more efficient for the road too.

However... the good news was... that at just 1.3 bar, my car made 427.8bhp, which I am chuffed with!

This is the current IC set-up:




The obvious thing is to fit a pair of fans on the other side of the core to blow air through, although one concern is that it will obstruct natural airflow... or do I really not need to worry about this?

FACT: I am not changing the intercooler set-up, it looks awesome and I love it and want to try every avenue before I even contemplate this.

Ryan suggested wrapping the exhaust as you can see the bend on the Nur-Spec is VERY close to the IC, now on the dyno heat-soak caused by this was evident as the left-hand side of the core was a lot hotter than the right-hand side. However I think this would look naff (as much as I agree it would be effective) I don't really want to ruin the aesthetic look of the Nur.

I 'may' consider changing the exhaust but I do love the look of it as it is.

Also to humour me, does anyone know where I can get a cheap CO2 spray bar set-up from? (by cheap I mean £400 or less)

Please discuss and any ideas or comments are welcome.

[lockys96]

your exhaust is practically on the intercooler and you have a hole in the boot, that is like a grean house.

the bottom of the intercooler must be seeing 500c radient heat.

you need a sheet of heat reflective metal at least and top spal fans

[Dale_V]

it does look very tasty, how about changing the exhaust so then it just exits straight out of the left hand side? that way you wont have exahsut pipes doubling back on itself around the intercooler

[Century Motorsport]

Why the change?

Because the rev 3 head is better

[greeny]

Why the change?

Because the rev 3 head is better

We'l see

Old school rev1

[Chris]

As said, that exhaust is nearly touching the IC. It does look good, but fooking useless in practice.

How thick is the core of the IC? I reckon you will have to replace the exhaust, and possibly find a much better IC core.

Can't have it both way Look good, or go fast

[tarmac terrorist]

dont know where your air flow comes from could do with more pics ,but as an idea cut part of the boot floor out put an angled box behind it 2 fans on the inside blowing air through to the outside which will also draw air from side vents into intercooler & rap exhaust will try to come up with a drawing if you want