41 replies to this topic

[Mr Apex]

My SC project is reassembled (but running base map atm) and, predictably, there are a few head scratchers to sort - any pointers appreciated!

• Idle speed is high - 1500rpm - but every now and then settles down to 900rpm and stays there
• Transition from idle to low throttle opening is jerky and unpredictable
• There is a flat spot at around 2750rpm, just before it sets off like a cat with a banger up its bum
• On a run, the charge cooler water returns to the tank cold. I'm running the dual pass conversion and I haven't been caning it, just constant motorway speeds. Should the coolant only get warm when using the whine?
• I had the rear clam off and it was refitted by the paint shop after a respray, but the rear boot lit sits about half a centimeter too high now. Is that clam alignment and how do I fix it?
• I've fitted a Tullett 2.5" full system and it is unbelievably loud....is that normal? I had an S1 Elise with an Exige manifold and piper back box before and that was nowhere near as loud
• I've blanked off the larger bore vacuum pipe on the SC unit and connected the smaller bore pipe to the vacuum on the brake system. It looks untidy - is there a different solution out there?

Cheers....

[Phear]

• Idle speed is high - 1500rpm - but every now and then settles down to 900rpm and stays there

Mine has a tendancy to do this when cold, if I leave it for a while it settles down and then doesn't do it again.

• Transition from idle to low throttle opening is jerky and unpredictable

TADTS, improves when the engine is warm.

• There is a flat spot at around 2750rpm, just before it sets off like a cat with a banger up its bum

TADTS, although a remap will probably improve things.

• On a run, the charge cooler water returns to the tank cold. I'm running the dual pass conversion and I haven't been caning it, just constant motorway speeds. Should the coolant only get warm when using the whine?

Depends how cool but charge coolant won't get warm until you start to give it sustained thrashing (or it starts to soak up engine heat).

• I've fitted a Tullett 2.5" full system and it is unbelievably loud....is that normal? I had an S1 Elise with an Exige manifold and piper back box before and that was nowhere near as loud

My 3" tullet was phenominally loud, I replaced the CAT with a second silencer and its better. That said I thought the 2.5" was supposed to be a good deal quieter. Tullets aren't renouned for their quietness though.

[Mr Apex]

Thanks Phear, sounds as though it is all doing what it should. Will be interesting to find out how much difference the remap makes... I'm guessing that it smooths things out a bit? I don't know how much power it makes with the base map, but it is already hard to get the power down in the wet. Doesn't feel like it needs more go, but I'm sure I'll get bored with it soon and want more. On a different note, my old Lotus had lighter, more alert steering - the VX feels as though it has resistance on return to centre and feels as though it loads more than it should as lock is applied. I've got Nitrons and had a full geo, so everything should be in line. There is no slack in the steering, but concerned that a bearing may be seized in the steering column - has anyone experienced that?

[CocoPops]

What size tyres do you have on the front? That will affect steering. Re the vacuum pipes, can you take a pic?

[Goosenka]

Whose base map is it? Base maps do have a slight flat spot IIRC. When driving from cold the car does drive odd. As I understand it, it switches from a 'cold map' to a ' warm map' (?) which makes it feel under powered until warm. Mine still has the double rev on start up and then settles down. Maybe try driving it so the ECU can adjust?

[JG]

• Idle speed is high - 1500rpm - but every now and then settles down to 900rpm and stays there
• Should be at 900 all the time - could be your base map, but most probably one of the sensors
• Transition from idle to low throttle opening is jerky and unpredictable
• Can happen when cold - should be perfectly smooth once warm
• There is a flat spot at around 2750rpm, just before it sets off like a cat with a banger up its bum
• Thats the base map
• On a run, the charge cooler water returns to the tank cold. I'm running the dual pass conversion and I haven't been caning it, just constant motorway speeds. Should the coolant only get warm when using the whine?
• This is normal, even on track it never goes much above tepid.
• I had the rear clam off and it was refitted by the paint shop after a respray, but the rear boot lit sits about half a centimeter too high now. Is that clam alignment and how do I fix it?
• Suspect the catch is upside down, or incorrectly fitted
• I've fitted a Tullett 2.5" full system and it is unbelievably loud....is that normal? I had an S1 Elise with an Exige manifold and piper back box before and that was nowhere near as loud
• Thats a Tullet for you...
• I've blanked off the larger bore vacuum pipe on the SC unit and connected the smaller bore pipe to the vacuum on the brake system. It looks untidy - is there a different solution out there?
• Yep there is an OEM fitting which is virtually imposible to find. You need a corsa B vaccum connector

• 
  

Cheers....

[NickB787]

on the clam did you remove any spacers from under the boot where it bolts down onto the chassis

[Mr Apex]

Thanks for feedback Re the sensors on idle speed - any idea which ones to check first? Re the wheels size - 16" TDs with correct tyre size Re the clam - I don't know - the clam was removed and refitted by the paint shop - how many spacers should there be? re the Corsa B vacuum connector - does this adapt from the smaller diameter brake vacuum hose to the larger dimater required for the larger vacuum pipe on the SC? If so, that would be perfect...

[FLD]

One more thing on the 2750 flat spot. Mine had this on base map and remap. Turned out to be a poor connection to the fuel pump which gave low current to the pump and consequently low fuel pressure. No idea why it was an issue at 2750 but it was. Sorted the connection and it has improved no end. Back to back testing on a 2.5" tullet and 3" tullet gave the same results based on 4500 rpm, 0.5M and 45 deg up. Boot lid latch has spacer washers which space it down from the clam. I'll bet the body shop have fitted the spacers in the wrong place. You want both of them abover the latch.

[JG]

temp sensor is a good one to check (basicly just put a new one in)

it won't be a clam spacing problem, it will be a bootlid issue, 99% its a catch position (but could be a hinge mistake too)

Corsa B vaccum hose is large diameter, you also need a new one way valve which is large dia entry and large dia exit.

see it here:


here


here


and here

[vocky]

high idle speed - usually an air leak on the inlet manifold or the pcv is still connected between the inlet manifold and cylinder head

[smiley]

I had the rear clam off and it was refitted by the paint shop after a respray, but the rear boot lit sits about half a centimeter too high now. Is that clam alignment and how do I fix it?

In my case the boot rubber was not pressed on hard enough after replacement. Could be worth checking.

[Rosssco]

As per comments above really. Nothing there seems that abnormal for a SC with base map. I had a full 2.5" Tullet, and it was too loud for me. Replaced the rear silencer with a equivalent size Milltek which improved things a bit, but still not ideal if you don't like loud exhausts... I wear earphones alot Different conversions seem to have slightly different results. For example, even after remap, and when warm, the transition between idle / cruise and boost is still a bit jerky and the car still stutters on part throttle between 1800-2000rpm. Pretty bad when cold, not too bad when warm. This is where the limitations of the type of mapping them can do is exposed (although its still drivable, its very clearly modified IMO), and one of the main reasons I'm looking at converting to an improved or standalone ECU..

[techieboy]

For example, even after remap, and when warm, the transition between idle / cruise and boost is still a bit jerky and the car still stutters on part throttle between 1800-2000rpm. Pretty bad when cold, not too bad when warm. This is where the limitations of the type of mapping them can do is exposed (although its still drivable, its very clearly modified IMO), and one of the main reasons I'm looking at converting to an improved or standalone ECU..

I don't get any of those symptoms but have had many hours of part throttle mapping done. Still changing ECU and engine though.

[Bargi]

For example, even after remap, and when warm, the transition between idle / cruise and boost is still a bit jerky and the car still stutters on part throttle between 1800-2000rpm. Pretty bad when cold, not too bad when warm. This is where the limitations of the type of mapping them can do is exposed (although its still drivable, its very clearly modified IMO), and one of the main reasons I'm looking at converting to an improved or standalone ECU..

I don't get any of those symptoms but have had many hours of part throttle mapping done. Still changing ECU and engine though.

Same as Techie, my first map still had the flat spot a bit, second time I went in I mentioned this and CS went back and forth about 3 times with Steffan and it's very smooth now.

[Rosssco]

For example, even after remap, and when warm, the transition between idle / cruise and boost is still a bit jerky and the car still stutters on part throttle between 1800-2000rpm. Pretty bad when cold, not too bad when warm. This is where the limitations of the type of mapping them can do is exposed (although its still drivable, its very clearly modified IMO), and one of the main reasons I'm looking at converting to an improved or standalone ECU..

I don't get any of those symptoms but have had many hours of part throttle mapping done. Still changing ECU and engine though.

Mine was probably mapped as quick as they could do it, as I had to get on my way. Plus minor engine bay fire didnt help with schedule.. LSJ ECU + B207 / Z20NET is looking the easiest option for me, infact looks like my winter project...

[techieboy]

LSJ ECU + B207 / Z20NET is looking the easiest option for me, infact looks like my winter project...

T'is what I'm doing (the engine has been sat here for over a year now) the soon as Joe pulls his finger out. Going to stick with 2 litre as well and not twat about with cranks to try and restore capacity.

[Rosssco]

LSJ ECU + B207 / Z20NET is looking the easiest option for me, infact looks like my winter project...

T'is what I'm doing (the engine has been sat here for over a year now) the soon as Joe pulls his finger out. Going to stick with 2 litre as well and not twat about with cranks to try and restore capacity.

2L, lighter crank, square bore / stroke ratio, lightened flywheel, balancer delete, better mapping and more linear throttle control - should feel significantly different to my otherwise standard 2.2... Don't think I'll miss any torque deficit for road use.

[techieboy]

Don't think I'll miss any torque deficit for road use.

That's the conclusion I came to. Doesn't bother me in the slightest if I lose 20bhp/20ftlb's. The benefit of the square dimensions, the easy mapability and lack of stupid aftermarket piston clearances are what appeals.

[Rosssco]

Don't think I'll miss any torque deficit for road use.

That's the conclusion I came to. Doesn't bother me in the slightest if I lose 20bhp/20ftlb's. The benefit of the square dimensions, the easy mapability and lack of stupid aftermarket piston clearances are what appeals.

From what I've read, you won't really loose any power, just move it a bit further to the right on the chart. Perhaps some low end grunt (but then again, I'm very rarely asking for WoT, so does it matter?) . Plus I'll probably fit a slightly smaller pulley (maybe 3"?) and get it mapped to suit. Benefit for me is that I can / have fitted a bolt in engine job and some additional wiring, but can't / haven't rebuilt an engine, and as the cost for rods / pistons is about the same as a B207 engine..

Anyway, looks like the Z22SE is the gremlin..