MadaboutKitcars

I have been very remiss in getting involved on the forum - this is my second post and I've had a my 5exi for 7 years now :S I wanted to post as I'm embarking on a new project - clearly I didn't have enough fun building her the first time around so I thought I would have another go! My chassis had sadly started to rust - pictures before and after attached - (powder coat peeling on road accessible surfaces) so I've stripped the car, shot-blasted, hot zinc sprayed & powder coated which hopefully will future-proof it for a while! I'm also taking the opportunity to switch the engine from 125bhp (AGN) to 225bhp (BAM - written off TT Quattro @ 66k ) - I hope I haven't underestimated the amount of effort this will all take, and how much more rapid the car will be when re-assembled!

Good luck with that! :-)

Just coming to the end of a rebuild myself. Nearly 2yrs now. No engine swap though..!
I've posted mainly on the MOC site as I didn't find out about Madabout until sometime afterward.

Hi and welcome

One of the decsions you are going to need to make, going from a non turbo. What type of air induction. Chargecooler or intercooler. After market ECU or recoded VAG.

Well done re re-build, I have my fingers crossed that I'll get it up and running in the next 6 months or so although it's probably wishful thinking...

In terms of those decisions, any advice of what works will be greatly appreciated! Given it's mid-engined and I don't wish to run boost pipes all the way to the intercooler bracket in the front I was planning on using a chargecooler and piping to a second front radiator- unless there is sufficient airflow in the back to cool sufficiently (modify the bodywork to increase airflow)? For air induction I was planning on keeping my current conical K&N air fliter (unless I've misunderstood your question...)

The wiring is going to be complicated - I currently have a recoded VAG ECU but I've just discovered the new ECU from my turbo donor car is different. If I go the recode VAG route I imagine it would be more sensible to keep the ECU that is paired to the engine and swap all the connections on the car side loom to the new ECU socket, then recode the ECU. I don't know anything about aftermarket ECUs - I imagine you get more control over the software but I don't know how easy it would be to wire up.

Sorry for the lack of a response.


Yes, I went the charge cooler route. I went for the cheap mustang chargecooler from ebay which sits just behind the engine on the rear firewall. But in my experience, is not a very efficient charge cooler going by inlet temps. Not a cheap route but got most of the bits (excluding piping) from below. I would spec the chargecooler for more power than you are planning at present 300+ is quite easy to achieve on standard internals.
[url]www.chargecooler.co.uk/[/url]


5EXI VAG owners have gone all sorts of different routes. Depending on there choice. Some have completed the own complete wiring looms. I just used the original 5EXI loom (Rover) and tapped into that with the Rover dials. Only extra for conversion I needed, was a different temperature sender to work with Rover dials. Which is just a screw in to the engine.
Aftermarket ECU will be no different wiring wise to a VAG ECU. Still need to match wire for wire where to connect up.

At this stage, you have a big discussion to make. The cost and work involved in the future, will depend on it. Stay standard'ish power or breaking the 300 barrier in the future. Wiring in standard, then have to rewire for aftermarket, redo piping for turbo etc for more power.
If over 300+, I would recommend the aftermarket ECU route. Bigger injectors, turbo, etc. Have more control for mapping (Also another cost consideration). Also very easy to data log and diagnose from ECU.

Hope that helps.

It's been a long time but I thought I would give an update - have finally gotten the car back on the road! Loads of fun - especially given the hot weather

Ended up going with the original ECU (defeated immobiliser and had the EVAP/SAI/downstream lambda removed) and a chargecooler

A few things to still work out. Coolant temperature is one - does anyone run an up-rated radiator? I'm fairly sure I'm running the original rover rad. Seeing coolant temps up at 110-115C if you really push it on a hot day. I imagine this is coming close to the limit of where you want to be. Discovered, however, that if I remove the number plate from infront of the air intake and stick it to the bonnet you can get it down by 10C which is a good start!

Second issue is boost pressure, which is proving baffling. Boost is stuck on the actuator pressure (max 7psi). Logging the ECU with VCDS shows requested boost at 14psi, but the ECU doesn't control the N75 to match - the duty cycle is stuck at 0%. Engine will rev all the way to 6k, so doesn't feel like limp mode and it's not throwing any fault codes. ECU can also switch the N75 with the VCDS output test, so it doesn't appear to be wiring issue, or problem with the valve. System has also been pressure tested and no issues - it's a bit confusing!

Picture of the build:

Interesting thread, I’ve recently bought an EXI with a rover K Series in, car needs some sorting and once the body/suspension is sorted I think the VAG engine conversion could be a plan. I take it you’re fabricating all the bits yourself, would be interesting to hear any lessons learnt!

I haven't had to do much serious fabrication - apart from the odd bit here and there: having access to a lathe/milling machine is very useful. I originally built the car with a VAG engine from a Seat Leon (normally aspirated), so the only new fabrication required this time was the boost pipes/chargecooler/intercooler rad/mounting etc (engine mounts all identical).

The reason I rebuilt was because the powder coat was starting to fail (nice excuse to put a bigger engine in while you're at it!). I had mine hot zinc sprayed and then re-coated so hopefully it will last a lot longer this time. Marlin should have the jigs for the VAG engine mounts so hopefully they can weld some up for you which would make life easier. I'm not sure if you would also have to weld tabs onto the chassis itself...

In terms of lessons learned I think they are all very individual to the build, as all the builds are different! I would say it's worth getting the cooling system routing sorted out - my first iteration kept air locking as the heater matrix was the highest point and it wasn't possible to put a sensible bleed point in without serious effort. Caused all sorts of worries as it would occasionally overheat! All in all it's a great project - but it's taken about a year and a half to get up and running again (it's quite a big job...). Happy to give more advice if/when you need it.

I got a new Rover rad during the build and has never got too warm, even on hot days. Bit of an unusual size the rad. So make sure you get the right one. Fan kicks in and gives you a blast of hit air!!

Could get a manual boost valve to try.

Or check actuator rod is not too loose. Should be half a hole out from connecting pin. Then just need to pull it that half a hole to connect up.

Well done on build

Thread on radiator


http://www.madabout-kitcars.com/forum/showthread.php?t=1656&highlight=Radiator

Thanks for the radiator thread - I'm fairly sure I'm running the same one (or something very similar). Have you had any experience with the manual boost valve? Actuator rod is good (I think it it were loose I would have an overboost problem?). I'm currently bothering all of the AUDI/VAG garages near me to see if anyone has any ideas - it would be a shame to come all this way and not be able to get it working as originally intended!

Did have one, when I had the Rover T16 turbo engine in the Marlin.
Is very instant with boost once it comes in. But might be a way of troubleshooting. Get a decent one as well. Have a word with Grant at GB Enterprises.

Think your right with actuator rod. But might be worth checking adjustment just to rule it out. Simple check/fix.

Thanks for the suggestion - had a chat with Grant and it seems like an aftermarket electronic boost controller is the most straightforward route to fixing my problem. I'll be digging around in the ECU for ages otherwise...

Ended up taking the car down to Grant and got it on the dyno (replaced the ECU with an aftermarket LINK ecu in the end to solve my boost issues). One thing that's come out of it is apparently the chargecooler is extremely inefficient with 220bhp being the current limit from inlet temperatures rising to 80C. Core of the barrel is 4"x10" (cylinder) which was apparently specced to 350bhp. Did you run into similar problems with your chargecooler setup?

I got high inlet temps with mine as well. I put it down to a cheap mustang eBay special. Which one are you using? Yep me from chargecooler.co.uk?

I bought the 4"x10" kit from chargecooler.co.uk (rated there for 350bhp apparently...), David from there seems adamant that it's plenty big enough. Grant tells me it's far too small! What sort of power could you make with your setup?

I made 305 bhp with mine.

Wonder if it’s the actual water getting too hot to cool down the air.

Wonder if it’s worth plumbing in a temp sensor or a temperature gauge even temporary.

Something seems to be a little off here then: do you know what the core size of your chargecooler is? I'm told by Grant that the water isn't getting hot at all in the chargecooler - as if the internal area isn't enough to take the heat out of the air...are you still running with your mustang eBay special or have you moved on to something more heavy duty?

Not not upgraded it. Was going to be on the oist of things to do, but not priority.

I was going to go for one of yours.

Did Grant recommend one?

Grants recommendation was that you buy the biggest chargecooler that you can fit in it..and that I need mine to be at least double. David (from chargecooler.co.uk) seems adamant that my setup is sufficient and that I've likely not got it setup properly. He's yet to persuade me though with any real facts - and Grant has all the data he needs from the rolling road, so I'm inclined to believe he's correct.

Bit of a random tangent, but what wheels are you running at the moment? I'm on 195/55R16, but having trouble on one side of the car at the rear where it's rubbing on the bodywork. Not sure if it's best to try and alter the arches (which ideally I don't want to do) or try changing the wheels. Unfortunately I can't run lower profile tyres as the ride height can't go up much more to avoid potholes (I'm almost locked out on the dampers in sag at the moment). If I added 10mm of offset and brought the wheels closer to the car it might work - but I don't know if this will have a large impact on performance. Any ideas?

I'd ask David if you could borrow/try a bigger one. Even to try on the rollers to get some data.

I'm running 195/50/15's on mine. I have a spare set you could try.

I run 195/50/R15 which I calculate has a total diameter of 576mm.
195/55/16 calculates at 620.9mm.
This is a difference of 44.9mm or to put it another way, your wall height from the wheel centreline is 22.45mm more than mine which, depending on ride height/spring/damper settings could be part of why your wheel/s are rubbing.

Also note that there is a 4.4mph speedometer difference if you go to a smaller tyre (if I've worked my maths out correctly).

I can't understand why one side in particular is an issue unless there is a difference in bodywork or the rear is slightly offset (mine is...)

I think I'm running a rideheight of 120mm all round - due to the placement of the on-board suspension pickups I can't get much more height out of it without locking out on the arms (well - dampers, but I set the damper length to avoid locking on the arms!). If I move to your wheel size this will lower the car to 100mm all round which I fear will cause problems on the potholes.

There is a difference in the bodywork left to right - but not a huge amount I can do about it, it's just in the nature of the finish (deviations are small ~10mm or so, but enough to make a difference).

Not quite sure I follow about the rear being slightly offset: do you mean if you measured from the centerline of the chassis (parallel with the direction of travel of the car) that one wheel would be further away than the other?

Also - when you have your camber set up properly, do the tops of the wheels protrude from the arches? If not you may be running more offset than me.

PS. Thank you for the offer of trying out the wheels, but I fear it would lower the car too much...also, Grant unfortunately didn't have a larger chargecooler to hand - and it probably needs something custom to fit.