Technical Help Required........please

[clutdav]

Howdy Everyone,

I am at my wits-end with my car at the moment. I have invested in some stage 2 performance mods and the car won't make any proper power. I have waited until this morning to calm down as if i had come on the forum last night I would have been posting a for sale message. Just to set the stage the car already has: -

1. K&N Typhoon CAI
   
2. Prodrive Downpipe
   
3. 2.5" Exhaust System
   
4. Decat Centre Section
   
5. Walbro Fuel Pump
   
6. Remap to produce 332bhp & 320lb.ft on the standard VF35 turbo
   

I was quite happy at this performance level but had a hankering for more. So I invested in a AF TD05/6 20G turbo, decat downpipe, uppipe, ported & polished headers, breathers vented to atmosphere & remap. And I trust the people I have had work on the car both in terms of mechanical and mapping.

There have been a number of small issues that stopped the car from being mapped correctly but they have been sorted and I had high hopes for the mapping session yesterday. Nope the car is DOWN on the previous tune level. It is ONLY making 320bhp & 315lb.ft. The mapping is all fine as there is nothing wrong with timing, fuelling, boost or duty cycles. The mapper says it feels as though there is a restriction somewhere in the system. The car doesn't have any boost leaks, exhaust leaks and the uppipe and downpipes are all heat wrapped.

I am at a total loss...............if anyone has any ideas please feel free to voice them as I need help. Thsi has been a monumental disappointment and has cost a fortune to boot. I'm not chuffed.

Still thinking of looking for another car.......................

Dave

[drb5]

When does it hit 1 bar of boost and when does it hit max boost? Out of interest, what IS max boost anyway?

[clutdav]

When does it hit 1 bar of boost and when does it hit max boost? Out of interest, what IS max boost anyway?

The car has no problem with it's boost control as stated in the first post. It does however make 1bar by around 3k revs and max 1.6bar at 4-4.5k revs then tailing off to 1.4bar across the remaining rev range. The turbo is making boost and holding it - but the car doesn't make realistic power for the modifications made. There is some sort of restriction................somewhere.

And I have no clue where................

Dave

[clutdav]

Come on guys over 55 views and only one reply. Please I need some fresh ideas.........

Dave

[AlanG]

Ported std headers?

I'd reckon around 350ish though if that's the case. Fuel used will dictate as well.

Re-check duty cycle. It should be much the same if the power is the same.

Not sure if the air filter will start to become restrictive for what you're aiming for, i don't know the filter.

Also a 3" system will help for power rather than 2.5" cause it's indicating a quick spool up.

Edited September 5, 2007 by AlanG

[drb5]

I'm wondering if your intake pipe is collapsing? Could be a bad one, you never know?

You think 1.6bar with a 20g on a 2 litre, is quick spooling at 4-4.5k revs Alan? I've never had the 20G on a 2 litre, so i'm not sure at what point it should be hitting 1.6.

How does the car feel mate? Feel any faster from what you can remember?

[AlanG]

I was going by hitting 1 bar at 3000rpm Dave.

The boost control for 1.6 bar at 4-4.5k *may* be dictated by other things such as surge maybe? If there is any seen?

[drb5]

Surely that wouldn't then have anything to do with the lack of power though?

Was the turbo new Clutdav?

[AlanG]

If the exhaust is restrictive, it won't let the gasses out quick enough at the upper rev range Dave and so will strangle power.

Remember that even though the 20g may be boosting to the same level as the previous turbo, the 20g will be flowing more "volume" of air, which means there will be more volume of exhaust gas to come out.

I'm not saying that is the case here as i know nothing about the car, but is a suggestion. I believe the system is 2.5" throughout?

Edited September 5, 2007 by AlanG

[clutdav]

I have been thinking about the induction kit but it was good enough to flow at 330bhp with the standard VF35 turbo as was the exhaust system with a prodrive cat downpipe. That should have been more restrictive than the new decat downpipe. This is just really flippin strange and annoying. Please keep the ideas coming.................thanks everyone.

Dave

[clutdav]

In terms of the boost that is what we have programmed the Ecu to take as the target values. And the car is doing exactly what we have told it to do apart from make proper power. The turbo was a AF exchange 20G not brand new.

Dave

[WUZ]

Ali37's car has produced over 350bhp and 338 torq on the VF34 and with 2.5" exhaust AFAIK ( the AVCS helped! ).

The AVCS on your car should allow for better spoolup as well as better top end.

If the 20G is producing the bost hten what is the airflow readings at 4k-8k on grams per seond? readouts will reconfirm the turbo is OK?

Andy doesnt do dodgy 2nd-rate rebuilds so I can say for sure that there is not an issue with the turbo.

Russell

[RA Dunk]

just a question, but who was the mapper anyway? surely the mapper could tell you what was happening?

[Boyakasha]

just a question, but who was the mapper anyway? surely the mapper could tell you what was happening?

I'm not saying anything

[drb5]

If the exhaust is restrictive, it won't let the gasses out quick enough at the upper rev range Dave and so will strangle power.

Remember that even though the 20g may be boosting to the same level as the previous turbo, the 20g will be flowing more "volume" of air, which means there will be more volume of exhaust gas to come out.

I'm not saying that is the case here as i know nothing about the car, but is a suggestion. I believe the system is 2.5" throughout?

Didn't Andy test the 2.5 system to over 400hp?

Why not say who the mapper is? We won't take it as though he's doing something wrong. lol A number of people have problems that have nothing to do with mapping.

[AlanG]

The "key" word in my post is "if".

I'm not saying it is restrictive, it is a suggestion.

Is the back box for example straight through? Or is it like an Sti box? A bit extreme maybe, but i had a 3" system on my car, yet 2 different backboxes gave two significantly different readings and was noticeable on the road at the same boost level.

It could be something totally unrelated to any mods done so far. It could be something like a cylinder down on compression. Unlikely, but who knows? We haven't seen the car and don't have sufficient information yet, to determine what the cause is, unless someone has done similar and has better results.

I'm wondering if your intake pipe is collapsing? Could be a bad one, you never know?

I don't see where it's mentioned, the inlet pipe was replaced? (Assuming you're talking about an aftermarket one)

Edited September 6, 2007 by AlanG

[clutdav]

Ali37's car has produced over 350bhp and 338 torq on the VF34 and with 2.5" exhaust AFAIK ( the AVCS helped! ).

The AVCS on your car should allow for better spoolup as well as better top end.

If the 20G is producing the bost hten what is the airflow readings at 4k-8k on grams per seond? readouts will reconfirm the turbo is OK?

Andy doesnt do dodgy 2nd-rate rebuilds so I can say for sure that there is not an issue with the turbo.

Russell

Yeah mate i totally agree with you. The turbo appears to be working absolutely fine. It must be something else. Anyway i thought you were on holiday?

Dave

[clutdav]

The "key" word in my post is "if".

I'm not saying it is restrictive, it is a suggestion.

Is the back box for example straight through? Or is it like an Sti box? A bit extreme maybe, but i had a 3" system on my car, yet 2 different backboxes gave two significantly different readings and was noticeable on the road at the same boost level.

It could be something totally unrelated to any mods done so far. It could be something like a cylinder down on compression. Unlikely, but who knows? We haven't seen the car and don't have sufficient information yet, to determine what the cause is, unless someone has done similar and has better results.

I don't see where it's mentioned, the inlet pipe was replaced? (Assuming you're talking about an aftermarket one)

The exhaust system has not changed between the two stages of tune apart from decatting the downpipe and installing an uppipe. FOr that reason I find it difficult to see why the exhaust woulld now be restrictive when it quite happily performed at 332bhp before. With regards to the inlet pipe, the K&N typhoon CAI has a set of 60mm hard pipes that relocate the filter into the front nearside wing. Now the mapper has suggesteed that it would be a good idea to either get a bigger filter or revert the induction back to standard with a high flow filter element as it works better with the MAF. But again nothing has changed on this side between the two stages and I struggle to see what is now causing the restriction????

I am slowly running out of hair to pull out..............

Dave

[drb5]

Alan i just ment, possibly the standard inlet pipe was collapsing.

What up-pipe was fitted fella? Might be the size is unsuitable....?

[WUZ]

Yeah mate i totally agree with you. The turbo appears to be working absolutely fine. It must be something else. Anyway i thought you were on holiday?

Dave

I am (0600 here and the little one is wide awake) but I thought it would be rude of me not to reply!

Ask the mapper to remove the CAI for one run on the dyno to see if that is a restriction

Alan - agree with you on restriction isues but this is a decent system with no visible ID reductions and very litlle bends.

Russell

[ally-b]

When Andy-F mapped my classic with APS CAI he explained that the bend in the pipework causes the airflow to swirl past the MAF and it only senses approx 20% of the actual airflow . His solution was to re-scale the MAF to give corrected readings to ECU.

This may be similar to what you are experiencing and , as suggested , it may be worth removing or replacing the CAI temporarly to see if it helps your problem.

Hope that is of some help ,

Al.

[WUZ]

Alan i just ment, possibly the standard inlet pipe was collapsing.

What up-pipe was fitted fella? Might be the size is unsuitable....?

H&S Slip-jointed Uppipe. OE Inlet so collapsing isn't going to be an issue.

Russell

[fai17]

Who map it?

Might be the exhaust that is holding it back..

A similar car (V7)with headers and APS CAI and 740cc and H&S system made about 375bhp recently

[AlanG]

Alan - agree with you on restriction isues but this is a decent system with no visible ID reductions and very litlle bends.

Hi Russell

I was meaning in terms of internal silencer design than the bore or number of bends in the system.

Looking at figures alone between the two set ups can appear to be disappointing, but you would need to see the figures under the curve and the maps to see what's going on i think. Peak figures don't necessarily tell the whole story.

I'd take the air filter off and see how the car performs. It's quick and easy and you should be able to feel the difference if the filter is an issue. Only do a couple of runs though, don't leave it off, but you'll know that anyway.

[WUZ]

Who map it?

Might be the exhaust that is holding it back..

A similar car (V7)with headers and APS CAI and 740cc and H&S system made about 375bhp recently

Not even remotely similar m8, this car has Variable Valve Timing (AVCS) for a start!

Russell

ps - Nobody wants to name the mapper for their own reasons, especialy me so we'll see if there are any issues that can be raised from the mappers opinions but my honest opinion would be to let Andy, Pat or Bob look at the datalogs and maps and see what they think!

Edited September 8, 2007 by WUZ