jonno's MKII Turbo

[jonno]

Well, I started this in 2002 with a rev4 GT turbo imported directly from Japan. I sourced the car for £8k with the intention of using it as my road car for a couple of years and then converting it into a track car. I had it about 4 weeks before I wanted more power and took it to Owens for a unichip - it was a total disaster, Owens said they put more boost in but the car just wasnt responding. When I got back home I did a compression test and found that number 3 cylinder was way down on compression.

I decided that a full rebuild would be a good idea, so I took it to Noble Motorsport's in Chesterfield. I told them I was looking for about 350bhp and intended to use it on track. At this stage the spec looked like this...

Motec M4 Pro ECU
HKS 264 Cams
CP Pistons 8.8:1
Owens Stage 4 CT26
Greddy IC

She made about 330bhp at the fly for 1.7 bar, but I wasnt really happy - the torque was missing low down and it was really intermittent, sometimes I would get loads of power sometimes it would seem really weak. Mark at Owens told me it was a cooling issue and that the turbo was producing way too much hot air for the size of intercooler I was running.

I then got in touch with Patrick, who had recently set up Rogue Systems about using a ST205 chargecooler. Patrick said he was actually working on a new system with Pace - I quickly volunteered my car to be used as a guinea pig!. Pace CC made a dramatic difference, it went back to Owens, had some fuel removed and she hit 365bhp.

About this time my turbo died a sudden death on track, when the air filter pipework came loose and it sucked in a foreign object - bang!.

A few phone calls and I had myself a reconditioned GT28 from Fensports Celica!. This was fitted, but it was obvious something wasnt quite right. It felt more torquey than the CT26 but the top end was pretty weak. Almost 12 months passed, with blame going from CC to Turbo, over and over until Dino contacted me with a view to test out his new CC core, which he felt would be perfect for my use.



We fitted the new CC core which made a dramatic difference, however disaster struck on the way home, the block cracked on cylinder #3. I always knew that the later rev3 blocks were prone to cracking - now I had found out the hard way!.



Build #2 was really straightforward, same components except for JE pistons (off the shelf) - new thick walled block was used too!. The new build felt better from the start, although we had teething problems with the head gasket and valve train.



Once these were fixed the car was running really sweet - actuator at 1.2 bar and she was flying. A trip to Dave Rowe at Motec to get some more boost put through her and more problems began - the turbo just wouldnt make any more than 1.2 bar at redline. Lots of head scratching and I eventually sent the turbo back to Turbo Dynamics - they delivered the bad news - its knackered mate, aluminium stuck in the exhaust wheel which is making it out of balance. They recommended using a slightly different turbo, a GT3071 - rated at 450bhp and it was much more efficient that my old GT28, they could re-use most of my turbo except for the "middle bit".

The new turbo went on - the difference was amazing! With a 1.2 bar actuator and the Motec boost control switched off the car pulled like a train, it was easy to control, making loads of boost by 3.5k and was an absolute dream!. Another trip to Dave Rowe and we had a flat 1.7 bar boost curve, loads of ignition advance and it was making loads of power.



The head gasket issue reared its ugly head again during this mapping session, so we stripped it again and sent the head of to an expert. He said the finish put on by the previous maching shop wasnt good enough - he fixed it up and sent it back. We slapped it together, all ready to test and then the prototype CC core I fitted last summer sprung a leak and poured water everywhere!.

So, now I have the car making loads of power - HG is fixed and im just waiting for Dino's fabricators to send me the all new CC core and super new front rad. Once thats installed shes all done - honest



Current spec

Motec M4 Pro (Dave Rowe!)
HKS 264 Cams
JE Pistons (9:1 cr)
Garrett GT3071 Turbo
Dinos CC and Front Rad
TRD Rear Diff
335mm big brake upgrade (front and rear)
TRD ARB
JIC Front and Rear ARMS
JIC Lower Brace
Cusco Strut Braces
Custom Suspension
235x40x17 Front
255x40x17 Rear
Defi BF's (Fuel Press, Oil Press and Boost)

Plus loads of other stuff I have forgotten...



Neil.

[Mark Edwards]

What boost pressure are you hoping to get it up to in the end?

[jonno]

What boost pressure are you hoping to get it up to in the end?

Im really happy with it as it is right now, although I doubt it will stay that way for long!!.

There is no reason I cant run 2 bar - I just need to swap the MAP sensor and get DR to fiddle with the ECU map.

With my sensible hat on, I would like to run over the summer as it is at 1.7 bar and see what the temperatures are like on track. Its amazing what happens when the ambient temps hit 30 degrees and I really want to make sure the cooling is right before we push any harder

[jonb-]

I'm trying to get my hands on one of those cores, look rather lovely Guess i'll make do with my ST205 for now.

Love the brakes too

One question, is that much power really needed for track or do you wind back the boost? Not only would i not want to put that much strain on the engine for anything longer than 1/4 I can't imagine the car is the easiest car to control accelerating through bends.

Also if it's a track only car why didn't you go more aggressive on the cams?

[Mikejc]

I'm trying to get my hands on one of those cores, look rather lovely Guess i'll make do with my ST205 for now.

Love the brakes too

One question, is that much power really needed for track or do you wind back the boost? Not only would i not want to put that much strain on the engine for anything longer than 1/4 I can't imagine the car is the easiest car to control accelerating through bends.

Also if it's a track only car why didn't you go more aggressive on the cams?

It's not so much the headline power figure that makes or breaks a track based car but the way in which it delivers it. If for example you have a car pushing 500bhp but comes on boost with a big bang at say 5000+ rpm you'll have trouble using it's power out of the bends. On the other hand, if you are able to access this power much lower in the rev range, say at 3000 rpm, the delivery of power is much more linear and so more manageable

I know that Neil hasn't taken the car as far as it could go because he does feel that he has it at a very sweet spot in terms of power and delivery at the moment. I'm sure Neil will explain in more detail though so i'll leave the rest to him

Mikejc

[jonno]

....One question, is that much power really needed for track or do you wind back the boost? Not only would i not want to put that much strain on the engine for anything longer than 1/4 I can't imagine the car is the easiest car to control accelerating through bends.

Also if it's a track only car why didn't you go more aggressive on the cams?

Once Dave Rowe mapped the car it became much easier to control - even with the extra power. Like Mike says, its all about delivery and confidence. If you can predict exactly whats going to happen you can keep the car right on the edge all of the time. By using more mild cams and a smaller model GT30 turbo, combined with some clever mapping we managed to make the car driveable from a little over 3k all the way to redline. Obviously on circuit you spend most of your time time above 4k, but that little extra lower down really helps in some places.

The worst track session I ever had for speed was with a MBC and the car was only making about 275bhp - it was lovelly until the MBC kicked in, then I was getting another 40 odd BHP dumped through the rear wheels with virtually no warning, v.scary coming out of Coppice at Donington

I know some other guys went more agressive on the cams and its worked out really well for them, but when I brought mine everyone advised against the 272's, so I took their advice and went for the 264's - well it was a long time ago, funny how things change

Also dont forget that cams are ALL about timing (obviously!) - a properly timed up set of cams is critical, and very difficult to achieve - just ask Andy Forster!!. I was amazed at the difference when Brian at Powerhouse timed up my cams - smoother and more power across the entire rev-range.

Having said all of that, if I was doing the job again now I would almost certainly go with the Piper staggered cams that Dino sells!.

Neil.

Quote : Dave Rowe - "You can never have too much power mate..."

[jonb-]

I've had this open all day waiting for me to reply so i better do it before i go to bed!

Thanks for the information guys, i totally get where you're coming from.

I guess my original point was made because i've been doing trackdays in sub 180bhp cars for the past few years and after a day in the turbo it seemed plenty enough to play with. There weren't many corners i could just sit planted like i could on past days Also even if i had an engine happy at 1.5bar i'd much rather run it at 1.1 (random figures) on track just to give me that nice window of no det.

Not sure what my next mod will be on the engine, any advice? I've an ST205cc setup to go on and an TB downpipe, figured i'd stop at that (i've the usual apexi / departure / hks BOV) as i like power delivery to be smooooth. The only other thought i've got is some fruity cams and an ECU to control it all (apexi possibly as i can't afford motec).

Oh, and an EBC of course to tame the extra boost the CC / Downpipe will probably give me.

[EarL]

With the mods that you have and the state of tune that the car's in, what sort of power/torque is it producing at the wheels Neil?

...and, what brakes are they? They look like the HiSpec calipers, but I didn't know they did them for the rear.

[jonno]

With the mods that you have and the state of tune that the car's in, what sort of power/torque is it producing at the wheels Neil?

...and, what brakes are they? They look like the HiSpec calipers, but I didn't know they did them for the rear.

We havent dyno'd the car in with this map yet - Dave Rowe calculated it was somewhere in the region of 430bhp at the fly, based on the Lambda and fuel. It feels pretty quick though

As for the brakes, I got HiSpec to do me a 335mm rear disc kit and then I measure up for a brake mount to shift the stock rear caliper out enough to get the big rear disc in - works well enough and it obviously gets around the handbrake problems!

[EarL]

Thanks Neil,

I'll give them a bell and see what they can do for me.

EarL.

[Jimbob]

Hi Jonno,

Just wondering, How you rated the GT28, I know you liked it originally. I'm hoping for 300-350@wheels so the 3071 might be slightly too big, plus i'd probably go with slightly smaller exhaust cam.

I'm really after a quick spooling, quick, safe setup, not pushing the block too hard, any tips? As it seems to be th downfall of many

Cheers,

James

[TBDevelopments]

GT3071 WG with the t28 footprint would probably do you buddy. Quicker spool than the t3 footprinted version.

Tim
xxxx

[jonno]

Hi Jonno,

Just wondering, How you rated the GT28, I know you liked it originally. I'm hoping for 300-350@wheels so the 3071 might be slightly too big, plus i'd probably go with slightly smaller exhaust cam.

I'm really after a quick spooling, quick, safe setup, not pushing the block too hard, any tips? As it seems to be th downfall of many

Cheers,

James

I was impressed with the GT28 after running a CT26 Hybrid, but neither come close to the GT3071 - We actually had to add extra fuel under 4k since it was spooling earlier than the GT28!. I suspect this was to do with the changes we made to the actuator location as well as using the new superlight compressor wheel.

Overall my advice would be to pick your desired BHP, add 50 and then buy a turbo to match. If its internally gated, spend LOTS of time to ensure that the actuator is working as well as possible, otherwise you wont get the best out of your turbo since the wastegate wont be operating properly, giving you poor spool-up and boost holding problems.

Neil.

[matt_mr2t]

xxxx hell mate you must have spent a fortune!!
Your engines been open more times than Heather Mills leg(s)

[TBDevelopments]

why you think i'm working on a package to allow any turbo i supply to be fitted with an external wastegate

Remember us having a chat about it at nobles.

I take it your GT3071R is the one using the T3 Flange over the GT3071WG?

Tim
xxxx

[Jimbob]

Can you divulge a little more about the acuator mods and the compressor wheel?

Thanks for advice.

James

[jonno]

Can you divulge a little more about the acuator mods and the compressor wheel?

Thanks for advice.

James

The compressor was recommended by Turbo Dynamics, essentialy its slightly longer and smaller in diameter than the previous wheel design - im not sure but I would guess they are standard on the 3071 now, at the time it was pretty new.

As for the actuator, TD spent considerable time making sure that it pressed at a right angle against the wastegate, otherwise it doesent work as well and you end up with undesirable results.

[tonigmr2]

So that's on a standard manifold with adaptor is it?
T

[Jimbob]

Cool,

I guessed thats what you were eluding to on acuator. I've seen some dodgy set-ups with brackets at all sorts of angles, spose its the detail that gets the results rather than chucking on a host of bits and hoping.

Anyway looking good mate, keep us posted of any further developments. Think i've decided on my turbo now Where did you source yours from?

Would you consider welding up wastegate and running an external? I'm guna have to make an adaptor anyway so could easily add an external in the mix.

James

[TBDevelopments]

i never understood that jonno? why not just go to an external wastegate set up?

Tim
xxxx