Bit of a curates egg...it's a long story: are you sitting comfortably? Then we'll begin

Ever since Simon mapped the car earlier this year it has suffered from idle problems. It seemed to be related - I thought - to the dumpvalve; or was it a sticking idle control valve; or maybe a leaking intercooler pipe; or perhaps a split in the turbo intake pipe; or blown exhaust manifold gaskets; or uppipe gaskets. In fact, all of those things have gone wrong at various times and they've been sorted, but still it idled badly, often stalling at traffic lights when the car came to a stop.

So, having fixed all those niggling faults, I booked a session with JGM at Surrey Rolling Road earlier this month to see if he could tweak the map to improve the idle.

As soon as the car was on the rollers, Charlie turned on the big fan...and I could see the two of them scratching heads and then nodding sagely. Fan off, out of the car, and they told me that it was now obvious why I had an idle issue: the airflow from the intake in the front airdam for the induction kit was changing so dramatically as the car decelerated that the MAF and ecu couldn't work out what was happening. It didn't "realise" it needed to go into idle mode. The change in air flow as the fan was turned on/off had replicated the issue!

Couple to that the huge air needs of the turbo, and it became clear that the only fix was to move away from the stock ecu or, more to the point, to go MAF-less.

That was not really a surprise as Simon had always said we were pushing the oem ecu and ecutek to the limit, so I'd always planned to go to a Simtek, but ideally not until next year. But a quick chat with the two of them and a deal was struck...and a Syvecs ecu was ordered

The Syvecs has 8 maps, and Simon agreed to do 4 main maps: 95RON/bad fuel; VPower; Vpower+10% Methanol; Vpower+20% Methanol. And then a Vpower version with antilag just for a laugh

I also decided in a "f*ck-it" moment to refit a decat centre pipe to get the absolute best out of the setup.

So,on Tuesday , I drove up to Surrey Rolling Road with high expectations

There was an initial hiccup as the JDM version of the ecu didn't work at all. Nor did a second one. A quick phone call to the manufacturer (Pat?) revealed that from '05 the JDM and UK ECUs had the same pinout unlike earlier years. Simon quickly rectified this by resoldering jumper links, refitted it and it powered up.

Then Charlie realised he had no "cal" switches (this is the switch that selects the maps), but he did have the parts...so yours truly set-to with the soldering iron and made one up

Simon then started mapping.

The Vpower-only map produced approx. 460bhp and the same torque. That's about 10bhp down, despite the decat, although the torque was much the same .

The good news is that spool is 600rpm better than before, hitting 1 bar at 3300rpm and 1.6bar at 3600rpm on the rollers (probably 3rd, but need to check) – and much better on the road where I’m seeing full boost at 3200rpm in 6th – very nice Probably the decat pipe, although the Syvecs is reputedly very good at controlling boost.

But it is still very puzzling why the power is down on that expected, and I still think the torque is low for a 2.5l.

Anyway, we then moved on to the meth map. To cut a long story short, as more advance was wound in and the cylinder pressures increased, the power graph started to show a pronounced downward blip between 6000 and 6500rpm. We then also noticed that the radiator was boiling over.

It’s possible I have a head gasket on its way out, although there’s no other evidence of it – the engine probably just got a bit hot on the rollers (it did the same at Castle Combe earlier this year with no ill effects).

The other theory was a weak valve spring…and I then remembered a comment made by Iain Litchfield when the turbo was fitted; he thought the engine sounded like it had a bent cam shim. Since it has always sounded top-end rattly, this seems like a reasonable theory.

At one point Simon saw 4 degrees of timing being pulled on number 4 cylinder…so sounds like that might be the culprit.

Bottom line is that the 10% meth map couldn’t make more than 475bhp - very very disappointing, although there is an additional 20lbft of torque.

So, as always with this build, it’s a case of one step forward and one step backwards. Without a doubt the engine is hugely smoother and more driveable on the Syvecs but it just can’t make the power it ought to.

It looks like it’ll need the heads-off for inspection and a general “refresh” in the near future…bad timing financially as I hope to get married in October, and we’re also buying a house. Oh well

But, to be positive, the improved spool makes a huge difference on the road and it's great to no longer stall whenever you stop at a junction

 

You're not having much luck mate are you!

Not to put a downer on things, what you suggest with the rad boiling I had the same problem a couple of months prior to the HG's finally saying "up yours!". I suspect that was the start of the inevitable happening.

How many miles has it done since the build?

 

About 25,000 miles, 11,000 of which was on the original VF37 before the LM480 was fitted.

 

I hasten to say.... par for the course imo on an OE block, 11mm bolts etc.

If they have gone pop I would use the Cosworth High Tensile bolts and Cosworth STOPPER Headgaskets.

 

Noted, Shaun. It's using cometic and ARP studs at the moment.

It has also been commented that the 2.0l JDM ('05 STi/Spec C) cams might not be ideal on a 2.5l. So if it is a head strip down job, might have to look at better cams perhaps

 

I have a 07 spec c , so 2.0L vf36 and now with 76mm exhaust ,air intake,map.
I'm undecided between lm 400 , lm 420 .

Now thanks you , I know the lm400 spool. But lm 420 ?Is so worse respect the lm400?

 

The Cosworth CAMS are very good bits of kit, but I was not aware that the 2ltr STI cams were not good for a 2.5ltr. I would personally save yourself some cash (the Cossie cams are circa Ł600+) and get hold a set of OE STI 2.5 cams if you can. Duncan's build using these cams has never been "short".

 

I will check with others (Iain especially of course) whether the observation on the 2.0l cams is valid...and thanks for the suggestion to use 2.5l STi cams

 

I do not know exact detail, but I do know it's obviously slower to spool than the LM400..... but spool should not be looked at in isolation. It's how much torque it makes which is important and can be gained by running more ignition, rather than boost. It's whatever the set-up is happier with.

Believe it or not I actually have slower spool on my LM400 now since the Tracktive map then I did when I ran the Litchfield basemap. HOWEVER, I have not lost anything down low in torque or power between the two maps and now run a shedload more ignition. So like I said.... don't concentrate on spool specifically.

Plenty of ignition makes it feel very bright, sharp and responsive..... that is exactly what I want from a road car set-up.

 

Is it really worth all the hassel? sounds like number chassing to me. If the car drives well and is better then before theres no point you throwing more money into as you might not get any further then it is now.
By the time you finished you would of spent enough money to build yourself a cosworth engine.

Immy

 

That's one way of looking at it!

 

Not sure if that observation is aimed at me? If so, yes I "hear" what you're saying

Had a long chat with Iain tonight (thanks Iain ) and he agrees that the symptoms really do indicate headgasket issues - or, more to the point, that at high cylinder pressures the heads can lift and/or the liners twist or bulge causing a temporary leak. This causes the boiling over. But once cooled down all is usually OK for ages.

So I may be OK for months and months, or they may go sooner; but they probably will go.

Once it happens, it's an engine out, heads off, then skimming of block and heads. Once it's all out and in pieces, it's a relatively small incremental cost to check/replace cam buckets, if that's the issue...and it*might* be worth fitting new cams.

Iain also recommended the stopper gasket and, ideally, 14mm studs or, instead, the newer 3rd generation cosworth 11mm studs. He also explained to me the machining that had been done to your block, Shaun, and suggested that was worth doing.

Final recommendation was some reworking of the LM480 as he's made improvements to the exhaust side of things that will definitely improve top end power

Bottom line - I don't need to rush in to anything, but have to expect the head gaskets to go sometime. Going on a track day in 2 weeks, so it'll probably be then

 

I'm not sure putting a step in the block AND using the stepped Cosworth STOPPER gaskets will be the right way to go. I had the step taken out of the block when the first rebuild was done, as the STOPPER gaskets (that were then used) are effectively doing the same thing. The additional upside to this was it meant we altered the compression ratio which REALLY IS worth doing in my opinion, if the engine is coming out. The difference it made on my build was extremely positive.

All this gas though was one of the reasons why I ditched the 2.5 and ultimately the Spec C. I can't be arsed with all the stress and just want something that runs first time, every time and I never have to worry about doing anything other than filling it up with petrol (which was exactly what I had with the OE Spec C engine). Quite frankly I can ram big BHP up my own backside unless I intend to use a car for competition use.

These types of builds have far too many compromises imo, as I want to drive my car hard.

If you need big bhp and reliability..... get a Porsche TT 996/997!

 

OK - might have misunderstood Iain regarding stoppers *and* block steps. Like the idea of increased compression - think mine's 8.5: what did you go for?

With hindsight, I wish I'd kept my 2.0l block, had it rebored and gone for a 2.1. Oh well.

 

9.?:1

My turbo flowed enough air for over 530bhp on VPower, yet it still made 1bar before 3k (although I did have the cossie cams and heads, but the heads are really not needed at this level imo) and that was on a SINGLE SCROLL turbo. At a paltry 1.4bar (low boost) it made 480bhp on Zen's rollers. More than enough power and very a conservative headgasket protecting boost level.

Regarding the 2.1..... that is EXACTLY the route I would take if I was to ever go internal again, but to be honest I don't see me doing that as you start to go down the same route again and I suspect it really is not warranted for a nice quick and reliable road car.

I must admit in ways I do miss the torque.... but I don't miss everything else that went with it! Best thing I ever did for what I finally decided I wanted out of the car.

It horses for courses and people want different things. What I want now is totally different to what I wanted a few years back and that is life.

 

Asked the question a couple pages back, but is anyone else having boost control issues? I dont know if the problem is isolated to me and my car, as I am now on a second exhaust housing and the issue is still happening. Need to find out if it is isolated to an issue with my car, or if there is a faulty batch of exhaust housings...

Videos of issues here:

http://www.youtube.com/my_videos?feature=mhum

 

Link above is only for YOUR videos via your login.... it won't work for anyone else!

Do not have any boost issues on mine.

 

No boost issues on mine either.

 

Sorry... try this:

http://www.youtube.com/watch?v=DtqSJm3oDLQ

 

I'm not sure what the problem is, as that video is purely showing the "crack" pressure for the actuator isn't it?

 

None on mine ...

Worth noting tho ... that I had started to notice the odd slip of the clutch going from 6th to 5th and booting it ... not unusual at this power and 65k miles from new .. so changed to an AP Race organic .... wow ... max boost alarms start going off on my gauges all the time ... and car is 'sprightly' to say the least ..

My gauge alarms were set just lower than what it was mapped for and what appears to have been happening is that there was undetectable clutch slip happening ie no obvious increase in rev noise or on the rev gauge .. and so the car was not hitting its target boost and was under performing.

So now that I've got some more clamping pressure .. I am a happier bunny again .. not totally happy as clutches ain't cheap, but I suppose I shouldn't complain too much as got fair wear and tear out of the original one.

And I have to say I really enjoyed myself on Sat when I attended a track day at Llundow Circuit in S Wales (excellent venue by the way) as I was overtaking all but the most powerful / tuned twin turbo MKIV Supras .. which I am lead to believe are approx 420hp ish as standard .. so not bad for a 400 odd bhp impreza .. and would have been even better if I'd have had a CAI and FMIC fitted .. maybe netx year ....

 

Yeah my bad.. put up the wrong video... this is the end result:

http://www.youtube.com/watch?v=vwHopPj0wSQ

That video was showing that it does work normally when cold, but as soon as heat is introduced something is expanding and resulting in what you see above.

 

We have not experienced any problems with sticking wastegates before on any of the turbos and we immediately sent Stephen a replacement (which was fully checked beforehand) and requested the original back for analysis. For this to happen on the second housing as well is very strange but once the original one is returned we hope to understand what is happening.
In the meantime we have sent details of some checks that can be done.

Iain

 

Was up at Litchfields today completing chassis modifications for the Hawkeye Project...... I also carried on discussion of the second generation of Litchfields LM's and progress thus far.

Snippet of public information about this second generation of LM's within the latest installment on my project thread in the Project Forum.

 

Billet

 

Dam a MK2 already. LOL

 

i putting mine on Powerstations rolling Road on Saturday 4th December. So should have a printout to post

 

can i come and watch?

 

It should make near as nuff 400bhp (as expected).... mine did on their rollers the other month!

 

Pm replied

Sorry not a billet version

Yes no problem

Yes should make it

Going to book it in next week with Iain for NPS mod/fix. As just been to busy to go before

I have had idle/low speed issues. Sometimes the is car starts up "cammy" at low revs and struggles to start Sometimes i switch it off and back on its alright

(i think) Iain said so will stand corected. Cams were sometimes fully advanced and it's was either issues with Neutral Position Switch and how it works within Megarom software . My NPS issues may not have shown a problem on my old EcuTteK software.
IIRC

Tony