24v Turbo advice

[DazzaVR6 2]

Right Gents and ladies,

Im after some advice on what people reccomend as I am starting to compile a list of information for when I start my project.

My question is what are your views on what to use. in reality I want to be hitting the 400bhp mark so I want to know what is best to use in regards to turbo, injectors, management etc etc.

This will be a long term project as funds will be as and when so I want to keep costs down to a minimum. This car will not be a daily so will be purely for enjoyment, shows and events.

All the build will be done by myself and I will be making what ever I can as I have a full machine shop at my disposal along with the fact that I work within tubing manufacturing so will be making my own manifolds and exhaust bits and bobs.

Any information will be greatly appreciated.

Thanks

[Gefstar 1]

What you need is one of these.....!!

[Gefstar 1]

And none of this....!!

[legvw 0]

Get a 630cc map from united motorsport, 4" maf, 630cc injectors, gt35 or hx35 or maybe bigger! A 2mm spacer plate from UM too, along with the largest intercooler you can fit up front should see you good. At least a Bosch 044 pump, possibly fed from a swirl pot, fed by your standard pump.

[Gefstar 1]

That rolled off your tongue a little too easily Paul!! - Been there, done that??!!

[legvw 0]

You could say that, but I'm sure others will agree.

P.s unless I win the lottery tonight I'll have most of the parts you need...

[craggsy 91]

As Paul says really. Everyone will say gt35 tho.

But 24v turbos are shit......oh hang on lol

[michael5556 247]

Paul covered it. Gt35 for the win.

[DazzaVR6 2]

Cheers Paul. To be fair I should of just sent you a message to be honest lol. Which 630cc injectors would you recommend bearing in mind cost?

[legvw 0]

Try not to scrimp on things, it will pay in the long run, but I've got Siemens deka I think?

[DazzaVR6 2]

No I don't want to scrimp as I want to get it right but I won't have the money for all top end kit unfortunately!

[craggsy 91]

I have genesis 550cc in mine

[matty.vrt 120]

i have Bosch 044 and 2L swirl pot for sale £100 if you require?

[RBPE 198]

HD Rod bolts and head studs if going the FI route, you can also get spacers from 7.8:1 to 9.5:1 so need to clarify (don't really need lower than 9:1 up to 2bar or so).

I'd go billet extended tip GT35 R, similar price to the GT35R if you know what you are doing!

Good budget options, I'd say:

http://www.ebay.co.uk/itm/Precision-6031-Entry-Level-Turbo-Charger-590-BHP-/300874888078?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item460d8a738e

http://www.ebay.co.uk/itm/Precision-Turbo-6262-CEA-Turbocharger-PT6262-AKA-850R-/120811338187?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item1c20eab9cb

May want to take a look at five-o's BDF 24V 1000cc EV14 injectors, still cheap even with duty/vat or try and get an answer out of Bosch UK.

[DazzaVR6 2]

Cheers for the input guys and please keep it coming! What's everyone's views on what compression to run with?

[MaidenVR6 26]

If goal is around 400wheel hp, go 9:1 cr. If you will have room for more power in the future, go with 8,5:1

You will not feel any diffrent in power. Turbo choise if on budget would be journal bearing Precision 6266 T4 0.68 or even 0.81. Or maybe a Bullseye S362 T4.

With a better budget it would be the same Precision, but ball bearing. Or 6262 or even the bigger 6466 Garrett GTX35R T4 0.82,

Sofrware and injectors i would go UM, and be done with it. Bosch 044 pump and a beefy clutch that will hold the torque you will get!

[DazzaVR6 2]

What's everyone's views on pistons? What sort of power should you really be looking to change?

[RBPE 198]

It's not really a question of power to be honest!

A spacer (9.0:1) will see you past 2 bar and 600hp if you do it properly. It's a question of piston speed, so don't go crazy with the rev limit and the VR6 is an undersquare design anyway so 500/500 is quite a good figure to go for with peak torque about the 5252rpm mark (about 1.2/1.3bar on fairly standard engine). It's also a question of pressure, the head lifting is something to take precautions over so why most will say go ARP or Raceware for the studs, much higher tensile strength and in design they have taken into account the extra height of a spacer. Other aspects too such as detonation and timing, sure you can pull more timing and run lower compression but your goals are fairly low, 400whp easily done let alone 400 brake with a VRT, so the old adage is true "it's all in the tune!".

As you are not adding extra height with low comp pistons this will naturally help but they are not strictly necessary, certainly not at such a low level. To maximise the FI rev limits will generally be higher and peak torque shifted to 5000-5500rpm so it's therefore this higher piston speed you need to take into account. Valve float is possible on higher revs with older springs that have had a lot of stress on them so HD springs are good if going over about 7k rpm. Rods can be known as the weak point but remember the bearings and bolts are rarely changed when people go FI so it's the old Von Mises stresses and torsional loads on the rods' bearings that are normally the killer.

So, to keep it simple; all you really need for 400hp on a VRT is:

Spacer (9.0:1 easily fine). ARP/Raceware head studs AND rod bolts, perhaps new rod bearings and main bearings if you are stripping the engine. O34 do coated ones if you can afford it but it's actually about the alignment & tolerances being correct on an older engine at those levels rather than overkill parts. Full gasket set, chains and tensioner etc and you'd be good to go.

After this it's rods and then valve springs if your piston speeds get higher THEN onto the pistons.

By the way, at about the 450hp mark you will get about 50hp more changing from a 2.5" downpipe to a 3" DP/system. Here's some orifice limits I did with some CFD software I am training on:

65mm = 576cfm/384hp

70mm = 669cfm/446hp

80mm = 873cfm/582hp

90mm = 1105cfm/737hp

105mm = 1504cfm/1003hp

Hope that helps.

[RBPE 198]

Meant flow restriction points, sorry (laminar to turbulent).

[DazzaVR6 2]

Cheers for all the info! Just what I'm after! Anybody have a rough estimate on prices for UM's software?

[FishWick 21]

And none of this....!!

Wow, that is erm, some beautiful welding :-) My first attempt at welding was a bit like that. I would certainly brush up my skills before taking a MIG to a manifold though!

OK, couple of things with 24V turbos. Don't take it as gospel. It's just my thoughts :-)

Engine model needs to be considered. AUE and BDE are 10.5:1 compression and R32 can be 11.3 or 10.8 compression, depending on MK4 (BFH) or MK5 (BUB), so spacer plate size needs to be considered. If going R32, the thickness of the spacer can affect the cam timing. HPA use a longer cam chain to get round this.

Or you can go forged pistons and get the compression and cam timing exactly right, but for the cost involved and the associated negatives, it's not worth it for mild boost applications.

If going 2.8 24V, personally I would go BDE/BDF as tuning parts are plentiful in the states. AUE has virtually zero aftermarket parts and it has the flimsiest intake manifold of all the 24Vs. It's a decent, strong and simple engine though.

BDE is also nice if you want to pop an R32 head on top for extra flow.

Turbo manifold. Personally I would use HPA's. It's expensive, but is by far the best I've seen, by a long, long way. It's properly partitioned to avoid expansion cracks and warping. The two banks are seperated upstream of the turbo inlet to allow correct lambda operation. i.e. 1 lambda monitor for each bank to ensure both banks receive the same fuel. Some manifolds dump all 6 ports into one collector, which kind of renders twin lambda pointless. Or another option is to build a short tubular manifold that bolts onto the stock cast/steel manifolds.

Intake manifold. Try and stick to standard and keep the boost sensible. You can use a short runner but the 24V suffers even more than the 12V for bottom end torque loss if you do that. Not so bad in a FWD application, but you'd miss it in a 4WD car :-) R32s have the strongest intakes and can hold a reasonable amount of boost. The ones that break apart are usually as a result of excessive boost or bad tuning / timing causing a backfire.

Injectors. If 400hp is the aim, is silly using massive 630 and 1000cc injectors. They're simply not needed. OEMs fuel for the job and no more and there's good reason for it. To keep the injector flow linear across the entire duty cycle. Nearly all injectors lose linearity below 2ms (where the flow becomes unpredictable), and curiously enough, 2ms is the injector duty VW use to achieve a smooth idle @ 680rpm on a stock R32. To get a 680rpm idle with 1000cc, you'll need to go waaaaay lower than 2ms and that's when things get messy and causes the lambda control no end of headaches. To get round that, people increase the idle speed instead, since more air needs more fuel.

Personally I'd go no bigger than 500cc and I'd also use the injectors the engine came with, so EV6 on all but the very last R32s, where they switched to an EV14. EV14 is a better injector but 95% of them are modified short bodies. I would get 500cc long body ones direct from Bosch personally. That'll be good for 500hp.

Turbo choice. Well that's an age old debate and it purely comes down to torque curve preference and how long you want the gearbox to last. The GT35 is a good turbo, but it's kinda old now. Plenty of newer, younger, shinier models are around now and the Borg Warner EFR series is making waves in the aftermarket. Again, it's not a cheap turbo but then the good stuff never is ;-)

That's it really. It's always the little things that seperate a very good turbo conversion from a poor one. I always keep the power to below the point where ridiculously harsh clutches and engine mounts are needed. 400hp is a very good number to aim for personally speaking. Cheaper to achieve and will last longer. OK, you won't win any internet top trumps but you will have a very, very fast car that'll put (most) of it's power down, can be daily used, sat in traffic for hours over 1000s of miles.

If you like your VWs served up OEM style, then you'll know where I'm coming from. If you just want hp and to hell with refinement. There's plenty of parts out there to help you do it.

And one last thing. Don't believe the hype. Very few people running big power will tell you the negatives. I've had more issues than I can remember running modest power and 90% of it was down to schitty quality aftermarket parts. Build once, build right. All these guys who rebuild gearboxes 3 or 4 times a year, honestly, where's the need?

And thereth end the lecture :-)

[craggsy 91]

That is the very reasons I love my car. It's a good reliable 450ish bhp, still got original inlet and I've had no mechanical problems. Ruined a clutch tho thro my own stupid fault!

I know a few other R32t and they have bigger injectors than I do, mine are 550cc genesis, andcthryvtun bigger power but most are not dailies like mine was up until October last year.

Mine does drive very well, but I would say that but tony has drove it back from the ring and says the same thing.

My only downside is money side if things. As everything costs more when it breaks, but I knew that before I bought it.

[Daverse 175]

And that kids, is what car tuning is all about

[VIW28 29]

I run UM Promaf software with my BDE with 870cc injectors, Promaf (obviously), Precision JB 6766 0.96AR with a Pagparts exhaust manifold and standard inlet. Haven't had it dyno'd yet but my guess is somewhere in the 400's bhp at 12.5psi, runs like a dream and has more than enough to completely annihilate my mate's C5 RS6

[DazzaVR6 2]

Cheers guy's. Would you say the US is the best place to source a turbo?