Prawn and BigAls A3 Track Car

[<tuffty/>]

looks good, dunno if anyone mentioned it here but i've come past some thread that it's more beneficial to actually giving an oil pump pulley bolt a tack of weld as they can come loose, it did on my mates cupra couple weeks ago, so far that the bolt cracked the sump open

Thats mostly due to people not tightening them up properly after removing the sprocket to remove/replace the pump... never had a factory pump do this on an engine I have built...

You can wiggle the pump on and off with the sprocket in place especially on a new build engine like Prawns but if you find you need to remove it then make sure the bolt is tight...
http://workshop-manuals.com/audi/a3...tion_system/removing_and_installing_oil_pump/

This is much like the interneterised information about the crank trigger wheel needing welding... this is again due to people not realising that both the wheel and the bolts are onetime use... once removed for whatever reason (some engine shops have been known to do this for balancing) they are toast... refitting them inevitably leads to their demise along with some of your engine...

IE used to ship stroker cranks with the trigger wheel removed but supplied new bolts... this is probably where the myth started as reusing the original wheel would lead to its failure..

Use a new wheel and new bolts you won't have an issue..

<tuffty/>

 

[badger5]

they dont come loose when done up with loctite

 

[Stuart B]

It was around this time that Andrew appeared. Andrew is a customer of Bills, and a long time lurker on here (Hello!) . The dark colourd S3 with orange roll cage and more than a few familiar looking parts would suggest he’s read a page or two of this thread too very nice to meet you yesterday Andrew, and I hope the thread continues to be useful to you! Best of luck with the S3 and it’s winter plans

.......
Massive Post
.......

I’ve got loads of annual leave left to take before Christmas, so once I’ve got a few things sorted out I’ll be booking a few chunks of time off and hopefully it won’t be too long before it looks like a car again!

Watch this space!

Well... at least your missus isn't a golf widow I suppose.

If you had got an S3 in the first place you could have saved yourself a whole heap of trouble with all this messing around trying to keep up.

 

[Prawn]

looks good, dunno if anyone mentioned it here but i've come past some thread that it's more beneficial to actually giving an oil pump pulley bolt a tack of weld as they can come loose, it did on my mates cupra couple weeks ago, so far that the bolt cracked the sump open

As Tuffty said, So long as it's properly tight from the factory, there should be no reason it to ever come loose, much like the famous trigger wheel 'problem' Thanks for the input though

All advice and thoughts are always welcome!

Well... at least your missus isn't a golf widow I suppose.

If you had got an S3 in the first place you could have saved yourself a whole heap of trouble with all this messing around trying to keep up.

Well, almost all advice is welcome I chose not to credit @Stuart B with a response to the above

 

[Prawn]

I managed to find a little more time in the garage over the bank holiday weekend, so I decided to get the Gaz Golds fitted, removing the KW V3's to sell.

Old kit out, and brand new SilverProject top mount offered into place:

The new factory top mount bearing sits perfectly in the Gaz alloy spring seat. The KWs had a plastic upper spring seat which I was never 100% comfortable with when abusing kerbs and the like on track!

The lower part of the SilverProject bearing sleeve then fits the OE bearing perfectly too:

As I've said before, technically, these OE bearings arn't needed, but when I tried using them without I found that asking the spherical bearing to take care of impact loading, angular change, AND steering rotation, it just didn't work properly. The weight of the car stopped the bearing from being able to turn properly, and they just binded.

Fronts installed:

Onto the rears:

Adjustable spring seat into place, I quite liked these. Rather than sitting on top of the beam like most other coilover rear spring seats, these have a machined lip and actually locate inside the large hole in the spring seat, then bolt up from underneath like most others. It's a neat solution, and ensures they're perfectly positioned:

Linear rate 550lb spring shown for comparison against the KW progressive rate spring:

Spring offered into place. I was a little worried at this point that once I bolted the shocks into the arches that the springs would not be retained. Having such shorter springs this was always a worry, but Gaz had assured me that the shock length would take care of this and stop excessive droop from dislodging the spring. To test this in it's most extreme case, I set the rear perches to be as low as they possibly could, giving the highest chance of a spring unseating. Obviously the ride heights will be adjusted, but it seemed best to test the worst case scenario and see if there was an issue:

Beam lifted, shocks bolted on, and beam allowed to drop again to check the springs don't become dislodged - Success they stay put!

 

[SHUk]

Looking good mate!!! Coming together well...
Curious, you didn't fancy having independent coilovers for the rears?

 

[Prawn]

I know some racers do it, but I didn't see any actual gains from it SHuk.

Whilst some cars with separate rear springs have crazy motion ratios around 0.5-0.6, the 8l platform actually has a rear MR that's not far from 1.


The shock mounting point is actually behind the axle line too, so converting to a conventional coilover at the rear gives you a motion ratio greater than 1.

The rear arches were also never intended to be load bearing, so I'm not sure what impact it's have on the shell in terms of flex etc.

If someone can give me a good reason why it'd be better 0n a conventional coilover type setup at the rear I'd definitely consider converting them though

 

[antwan64og]

Looking forward to you expertly corner weighting it once the motor is in, lol, i'm just jealous really.

Did you find the ideal height by trial and error last time?

 

[Prawn]

Trial and error with regards what felt right. Ride heights levelled with a tape measure on a very flat known surface. Careful planning when it comes to adding weight side to side meant that the corner weights were within 5-6kg side to side at each end of the car and the cross was very close to 50% too.

If I ever reach a stage where in unlikely to make any large changes I'll have it properly corner weighted, but for now some careful Diy seems to have served me well for the last 6 years

 

[Erikn89nl]

Wow, look at those page views!

Keep it up mate.

 

[IPG]

The new factory top mount bearing sits perfectly in the Gaz alloy spring seat. The KWs had a plastic upper spring seat which I was never 100% comfortable with when abusing kerbs and the like on track!

The lower part of the SilverProject bearing sleeve then fits the OE bearing perfectly too:

As I've said before, technically, these OE bearings arn't needed, but when I tried using them without I found that asking the spherical bearing to take care of impact loading, angular change, AND steering rotation, it just didn't work properly. The weight of the car stopped the bearing from being able to turn properly, and they just binded.

Fronts installed:

So using the Silver Project top adjustables there is no use for the top strut bush??? Is there a way to still have it in there for NVH ?

 

[Rainbird]

The SP top mounts are designed to replace the stock rubber mounts, so without some serious modification you're going to struggle to find a way to fit both.

 

[Prawn]

No way of retaining the rubber bush and using the silver project mounts. They're a performance item designed to tighten everything up and give maximum adjustability.

If you want to get some geometry gains and retain some level of comfort, have a look at eibach offset rubber top mounts. I had a set before I moved TO silver Project and they were a good road option retaining some compliance.

 

[antwan64og]

Any thoughts if you'll be moving enough air to warrant a Supersize diverter valve?

 

[desertstorm]

Great post Nick and perfectly timed. I am awaiting delivery of a Gaz Gold setup for the TT. Went 550Lb front and 850Lb rear for the springs as a starter.
There are a few people on the TT forum who track with these. I also purchased a SP top mount and I was wondering about how that rose joint was going to cope with all the steering loads and movement. I didn't realise the standard bearing would sit on top like that so will get some ordered. Part number looks to be 1J0412249 where did you get your bearings from as there are millions to choose from.

 

[Prawn]

Any thoughts if you'll be moving enough air to warrant a Supersize diverter valve?

Good question, and one I've been debating myself recently.

What is the NEED for the DV, excatly? on a mafless setup? It would be to relieve the turbo of suffering from huge compressor stall is my belief.

I get that on a MAF based setup it's also needed to vent the measured air back into the system so the ECU knows what it's taken in and what it's got to fuel for.

On my car, there is obviously no MAF. the 007 will vent SOME gas at least, I'd assume most of it, even if it's not capable of venting it all.

If it vents say 80%, and the remaining 20% is left in the system as low residual pressure, that'll cause some very mild compressor stall. An issue on kkk based turbo's certainly, but much less of an issue on a GTX.

Plenty of known 1.8T race cars running GTX turbo's run NO form of DV at all, be that a BOV or Recirc, so surely if I'm venting 80% of the air (assumed figure), that's better than venting none of it. Even if venting none isn't actually a problem anyway?

I'd be keen to hear thoughts from either side of that argument. My plan for the minute is certainly to start off with the trusty 007p, and take it from there if I do find a reason I need to opt for a larger DV. I'd probably go for a Tial 50mm BOV or similar, as I've not recirculated air for several years now.

Great post Nick and perfectly timed. I am awaiting delivery of a Gaz Gold setup for the TT. Went 550Lb front and 850Lb rear for the springs as a starter.
There are a few people on the TT forum who track with these. I also purchased a SP top mount and I was wondering about how that rose joint was going to cope with all the steering loads and movement. I didn't realise the standard bearing would sit on top like that so will get some ordered. Part number looks to be 1J0412249 where did you get your bearings from as there are millions to choose from.

Glad to be of help Carl!

With the 0.63 rear MR of the TT platform, that'll give you a rate at the wheel of around 535lbft. The A3 MR is somewhere around 0.9-0.95, so our setups should end up incredibly similar in terms of spring rates at the wheel. Fingers crossed we'll both get on well with them!

Top mount bearing wise, there should only be one option. It's the same part across all the chassis I believe, from A3 to S3, Leon to TT, I've certainly never seen any that are different. If you need any help when fitting at all just give me a shout!

 

[desertstorm]

Thanks for that Nick. I am debating what kind of camber/ caster settings to aim at and also pondering the rear set up. Bought a second hand set of the cookbot adjustable arms cheap enough so able to adjust the camber. Need to get some rear swing arm bushes as well but not sure whether to go for the ones that let you add some more toe or get another set of arms and then I would be able to adjust camber and toe to what ever I want.

 

[IPG]

Good question, and one I've been debating myself recently.

What is the NEED for the DV, excatly? on a mafless setup? It would be to relieve the turbo of suffering from huge compressor stall is my belief.

I get that on a MAF based setup it's also needed to vent the measured air back into the system so the ECU knows what it's taken in and what it's got to fuel for.

On my car, there is obviously no MAF. the 007 will vent SOME gas at least, I'd assume most of it, even if it's not capable of venting it all.

If it vents say 80%, and the remaining 20% is left in the system as low residual pressure, that'll cause some very mild compressor stall. An issue on kkk based turbo's certainly, but much less of an issue on a GTX.

Plenty of known 1.8T race cars running GTX turbo's run NO form of DV at all, be that a BOV or Recirc, so surely if I'm venting 80% of the air (assumed figure), that's better than venting none of it. Even if venting none isn't actually a problem anyway?

I'd be keen to hear thoughts from either side of that argument. My plan for the minute is certainly to start off with the trusty 007p, and take it from there if I do find a reason I need to opt for a larger DV. I'd probably go for a Tial 50mm BOV or similar, as I've not recirculated air for several years now.

See I had heard of this too when recently looking st what kind of intake, DV/BOV setup to go for! Goes against OEM setup... but apparently is ok???

 

[desertstorm]

Personally I would always tend towards a solution thats more mechanically sympathetic. All the components in the engine are working very hard and if you can make life easier for the turbo without affecting performance why not. You are less likely to pop off a boost hose or split one if you haven't got big pressure pulses being built up in the system. The rapid slow down of the turbine in the turbo when it stalls must put very large forces on the shaft bearings etc, In the short term maybe not so much of an issue.

 

[antwan64og]

Good question, and one I've been debating myself recently.

What is the NEED for the DV, excatly? on a mafless setup? It would be to relieve the turbo of suffering from huge compressor stall is my belief.

I get that on a MAF based setup it's also needed to vent the measured air back into the system so the ECU knows what it's taken in and what it's got to fuel for.

On my car, there is obviously no MAF. the 007 will vent SOME gas at least, I'd assume most of it, even if it's not capable of venting it all.

If it vents say 80%, and the remaining 20% is left in the system as low residual pressure, that'll cause some very mild compressor stall. An issue on kkk based turbo's certainly, but much less of an issue on a GTX.

Plenty of known 1.8T race cars running GTX turbo's run NO form of DV at all, be that a BOV or Recirc, so surely if I'm venting 80% of the air (assumed figure), that's better than venting none of it. Even if venting none isn't actually a problem anyway?

I'd be keen to hear thoughts from either side of that argument. My plan for the minute is certainly to start off with the trusty 007p, and take it from there if I do find a reason I need to opt for a larger DV. I'd probably go for a Tial 50mm BOV or similar, as I've not recirculated air for several years now.

In theory transient throttle response is better with recirc in fast on/off throttle situations, will be interesting to see how you "feel" the big turbo performs on this 1.9 track car.

Did you see Bill selling those fancy inlet manifolds on FB the other day..... Just saying

 

[Prawn]

In theory transient throttle response is better with recirc in fast on/off throttle situations, will be interesting to see how you "feel" the big turbo performs on this 1.9 track car.

Did you see Bill selling those fancy inlet manifolds on FB the other day..... Just saying

I did! And as tempted as I was, I think cams would be a far more worth while investment at the level I'm at.

Plenty of cars have made big figures with cams and a stock inlet manifold.

Very few have made big figures with a fancy inlet manifold and stock cams though! The money has to stop somewhere, so for now, stock large port manifold and NA cams should be plenty to see 450bhp. That could well be all I'll ever want!

Nobody could be more keen than me to see how it drives and feels! It's a bit of a leap of faith based on the known path trodden by those with far more experience than me, Bill races on a very similar setup, the front running CCSC TT (Tuned by Bill also) runs the same again. Many 1.8T race cars competing in other series around the country have chosen the 1.9 / 3076 combo. It just seems to be really ideally suited to the engine. I've been very used to super spooling hybrids and similar for so long, but in reality, I never really use the power before 4k at all, and on track it's usually above 5k, so I really don't think it'll be an issue.

I'm sure it'll take quite a bit of getting used to, and coming to terms with boost thresholds, and then the increased speed I'll be arriving at corners, I wouldn't be surprised if initially at least I'm actually a little slower before, but once it's all dialled in, and sat on some rubber more fitting of it's new power, I think it'll be very very fast indeed!

 

[antwan64og]

The money has to stop somewhere,

Lol

Exciting times ahead!

 

[Prawn]

Lol

Exciting times ahead!

I ****** hope so! Just a case of when it'll actually get done!

I've got 90% of the parts now, and most of the money has been spent, but it's just finding the time.

We're in holiday season at work, people off every week and nobody to cover me if I tried to take leave, so that's not an option. Weekend time is mainly family time now, so that's not going to progress at any great rate.

Diary is looking empty for October though, so I think I'll make sure I've got ALL the bits sorted and ready in September, then book some time off in October to get this complete, much like I did last year. a few 2-3 day blocks, with gaps in between for emergency parts ordering if required!

Max power to start with will be determined by my 630cc injectors. I'm going to fire it up and run it in on them definitely because I've already got the fuel maps for an AGU with 630's from my original engine on Emerald. With very little boost in it they will fuel just fine to get it run in. Then when I start tuning I'll very soon know if I'm going to run out of injector! I'll likely switch to Deka 875s afterwards if needed.

 

[Rainbird]

Happy to head across for the odd weekend or two if it helps. Even if it's just 24hrs that you can get a temporary family pass for, a couple of sets of hands might help things progress a little and relieve the frustration

 

[<tuffty/>]

a couple of sets of hands might help things progress a little and relieve the frustration

Fnarrr... What goes on in race car garage stays in race car garage!!!

<tuffty/>

 

[desertstorm]

Hi Nick, Gaz Gold stuff landed on the mat yesterday. I thought the front shocks would have helper springs on them as they are essentially the same as the ones you have. Did you specify helper springs on yours or have Gaz failed to provide them on my shocks.
All the pictures I can find of the kit I have are generic ones so not the actual shock and springs supplied.

 

[Rainbird]

Adjustable spring seat into place, I quite liked these. Rather than sitting on top of the beam like most other coilover rear spring seats, these have a machined lip and actually locate inside the large hole in the spring seat, then bolt up from underneath like most others. It's a neat solution, and ensures they're perfectly positioned:

Big fan of this. Relatively minor difference in principle, but very logical. Also interested to see how you get on with the linear springs vs progressive - provided you're in the right ballpark for rates you should do fairly well with them I'd imagine.

 

[Prawn]

Hi Nick, Gaz Gold stuff landed on the mat yesterday. I thought the front shocks would have helper springs on them as they are essentially the same as the ones you have. Did you specify helper springs on yours or have Gaz failed to provide them on my shocks.
All the pictures I can find of the kit I have are generic ones so not the actual shock and springs supplied.

That's a strange one Carl. I'd contact Gaz and ask about them. Mine certainly have helper springs, and I'll be keeping them.

Post a picture of your kit, it'd be interesting to see what the rear springs are like for the 4wd chassis too

 

[Prawn]

So, Oliver had an extrodinarily long nap on Sunday afternoon, so my lovely wife suggested I go to the garage for a few hours shes awesome!

Not wanting to get too involved with mechanical stuff, I decided to turn my attention to the inlet track.

First up, I offered my large port phenolic gasket spacer up to the AGU head, to see what I was dealing with:

I'm sure you'll agree, that step is probably not going to be doing the flow much good at all!

It turns out, my phenolic is an exact copy of the gasket profile, which is about 1mm oversize all round.

Easy from a manufacturing point of view, but far from ideal for flow.

I first thought about porting the head and manifold out to suit the phenolic, but soon decided this was a bad idea. I didn't want to increase port size any further than I needed to, as gas speed drops, and it's generally not something you want to do.

The second, and favoured option, was to port out a small port phenolic gasket to match the existing head and inlet.

Luckily, from my failed endeavors earlier this year with a small port engine, I had a small port phenolic sat around!

I used the gasket to roughly mark the port shape, and roughed that out with the dremel first, before bolting it up, then using a very fine sanding wheel I flushed the phenolic into the head first:

Then repeated on all 4 ports:

Offered up with the gasket, although uncompressed. You can see the gap where the gasket sits. When tightened down it's still a lovely smooth flow through:

Next up I bolted the phenolic to the inlet manifold, and used the dremel to ensure there were no steps in the wrong direction coming through the transition to the phenolic:

At this stage, I've left a small reversion lip around as it exits the inlet manifold into the head.

Speaking to Bill yesterday though, I've now ordered some dowels, and I'll be dowelling the head / phenolic / manifold to ensure there is zero movement, and porting the step out to make the inlet path 100% smooth.

I know it's only a small job, but I think it's the little things like this that will make the engine as efficient as it can possibly be.

It's all about the flow! (yes, I definitely stole that from somewhere )

 

[antwan64og]

When you're pushing 2 bar i'm not sure a hogged out inlet would reduce velocity much!

Looking back at my logs I gained a whole 7g/s at 6000rpm with a hogged out inlet manifold that tailed off to 2g/s gain at 6750rpm.

Not much I know but if you scale up a 200bhp ko3 to 500hp thats an extra 20hp..... For free in the meat of the powerband, at less boost.

Disclaimer: I don't know if you can scale up like that but it sounds good

 

[badger5]

Personally I would always tend towards a solution thats more mechanically sympathetic. All the components in the engine are working very hard and if you can make life easier for the turbo without affecting performance why not. You are less likely to pop off a boost hose or split one if you haven't got big pressure pulses being built up in the system. The rapid slow down of the turbine in the turbo when it stalls must put very large forces on the shaft bearings etc, In the short term maybe not so much of an issue.

slower response.. respool... fill and pressurise the pipe system again and again

 

[Prawn]

Cheers for the input Bill

For the sake of ease I'll just do without one at all to start with. Can always run one in my throttle body pipe if needed

 

[desertstorm]

Dropped an E-mail to GAZ they are posting some helper springs. Here is a picture of the kit I received.
The rear springs are 5.5 inches high.

 

[Prawn]

Funny little fat springs on the back of a quattro arn't they!

Glad to hear you've got the issues sorted so quickly. I've helped sort out supply of kits for a few people recently and a couple have had one or two tiny complications. Gaz have been remarkably keen and quick to help out on each occasion, which fills me with confidence when it comes to using mine and any after sales care I may need

 

[desertstorm]

Helper springs arrived, posted next day delivery.

 

[Prawn]

Good stuff Carl.

It's nice to know that the after sales service is decent

I've just ordered 24 new AP bolts, and 12 Reyland anti rattle shims so I can get my front discs assembled with the performance friction discs next week Just another job to get ticked off the list!

 

[Prawn]

Well, I'm a rare change to our usual circumstances I found myself alone this evening with some free time in the garage!

I started by finishing off what I started on the Inlet then other day.

First up was drilling for the dowels.

I measured up the total depth I wanted to get the dowels sitting flush in the manifold, and marked the drill bit to show where to stop

I drilled the head to 3mm, then the phenolic spacer to 3.3mm to allow the dowel pins to pass through a little easier. They are still a mega tight fit and need pressing on with some force.

I tapped the stainless roll pins into the head, and pushed the phenolic spacer on:

I then spent a little more time with the dremel matching the phenolic spacer and head exactly together:

I then bolted the phenolic to the manifold, and tranfered the dowel holes across, before test fitting it all.

As I'd hoped, zero movement at all.

I then bolted the phenolic to the inlet manifold, using some spare dowels to align it perfectly, and continued to remove the reversion lip I'd previously left and port match it to be completely smooth:

With them all done, I test fitted the manifold one more time, and confirmed everything seems as smooth as it can possibly be. I marked up and drilled the 2 gaskets for the dowls, and that's all now ready to go together when the time eventually comes!

Next task, was wrapping the tubular exhaust manifold. NOT a task I'd been looking forward to!

Not too many pictures, because this was a hateful task.
I'd dropped the wrap in a bucket of water as soon as I'd got home to soak, then removed it a few hours later. This seemed to help manipulate it whilst wet, although some people say it's not needed. I guess I'll know more tomorrow when it's all dried out!

Mid way through:

And done! As easy as that!

If I never have to do that again I won't be too upset!

I don't think either of tonights tasks were the most important jobs in the world, but I'm of the impression that every little helps, and it's all these little details that'll add up eventually!

Still, progress is progress. No matter how small these jobs are, they're now jobs done, and a few less things to do!

This isn't the fastest build on the planet at the moment, but slowly slowly, we're getting there!

 

[<tuffty/>]

Well, I'm a rare change to our usual circumstances I found myself alone this evening with some free time in the garage!

I started by finishing off what I started on the Inlet then other day.

First up was drilling for the dowels.

I measured up the total depth I wanted to get the dowels sitting flush in the manifold, and marked the drill bit to show where to stop

I assume you have stop mid update as Tori arrived home?

Feels very much like our chats on facebook with the extended satellite delay

<tuffty/>

 

[Prawn]

Thanks PTPK.
On this occasion I was having issues th the imgur mobile app. So transferred to a PC midway through my post!

 

[Prawn]

I'd like this finished now please. Anyone volunteering to sort it for me? It feels good to be making progess again at last. I've got this month to source all the parts I need, then October will be annual leave month, and I'm determined to get it back on the road!

Once this is done we need to do something about poor @Erikn89nl too. The poor bloke has been incredibly patient waiting for me to get this sorted so I can help him with his too!