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tim1010

12v AAA turbo build

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Hi newbie here, been touring to register for months but it has only just let me for some reason. Currently building a mk2 golf syncro/haldex set up with a turbo 12v AAA. Block has gone away for rebore today and fitting wossner pistons and pec rods. Will be using the 24v head gasket to get compression back up slightly. My question is I'm looking to run 5-600 Bhp on standalone management already have emerald k6+, was looking to have head potted with 2mm oversize inlet and over size exhaust super tech valves, with shrick 268s and springs and using a gtx3582r on a tubular manifold. Is this necessary or over kill? Currently havent bought cams or valves but will need to know in the next few weeks. Only found contradicting stuff so far online. Tia Tim 

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It's contradiciting because it depends really!

 

Displacement, revs and boost pressure (aka efficiency as desired) - they're the main ingredients for hp, how you go about that usually depends on budget and reason for high goals such as this.

 

Simply put - you can get this power from a fairly stock engine with a few mods as mentioned in many threads, but generally, the more you do the better.

I usually say for people to do the basics first, which would be refreshing as much as you can afford as the parts of your car have been used and abused over the years to a degree and then uprating the parts put under stresses (i.e. the engine, clutch, gearbox etc) as best as your budget allows. Once you do that then it is on to uprating stuff further which you clearly have done for the botom end with the rods and pistons.

Once that is done then it comes down to two things, the head and the use of the vehicle. The head is the crux of power (or efficiency to be more correct) in such a build and the more flow (hp) you are aiming for, the less restrictions the better. So uprating the head (or even just refreshing parts and uprating some things like harder springs etc) is a good idea if you can afford it. With most of these conversions though they are often road based cars so unlike a drag car "the area under the curve" is an important aspect to note, basically, ensuring good driveability and plenty of low end grunt so you don't have to drive everywhere at 6000+ rpms! Cams would certainly help you in this respect as you are going from an NA set up to FI and there are variances in the lift/aggressiveness etc of such cams, hence why many uprate them, in short, dragging your peak torque down to a more acceptable level for road driving. This also relates to your turbine side of your turbo as well as the tubular manifold mentioned - you also want the exhaust manifold to pulse the air flow out, thus driving the turbine wheel efficiently in the most laminar way possible and you don't want a big turbine ar if it only gives you good flow (hp/torque) at 5000+ rpms on a road car!

 

So it's basically this -  on a road car you need to balance the mass of air flow (which can be increased with big valve heads, big turbo's, free flowing mani's etc) all of which will get you these higher hp numbers you crave, the bragging rights down the pub, but you also want to keep good flow (efficiency) at lower gas speeds so the car remains driveable, on road cars it is this balancing act you are aiming for. If you can afford aftermarket cams, big valve heads etc then yeah, go for it, if not, then a good refresh of the head is a good start, stiffer valve springs are usually a good idea to handle the increases in revs you are likely to want for such power, then cams certainly can help your area under the curve and then onto valves etc after that.

 

You probably know this if building a big project like that but others might not and it really comes down to efficency where you want it and the balancing act that is aftermarket modifications for a road car!

 

Edited by RBPE
dodgy keyboard keys!

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Thanks for the very detailed response and has answered a lot of my concerns. Regards to the stiffer valve springs you mention,  are you pointing towards double valve springs or just an uprated single? I've found a few company's that do the double valve springs but they come with titanium retainers and have been warned by two separate people that these wear dramatically and would need replacing frequently, which obviously I dont want to be doing. Are you aware of any steel retainers for double valve springs or is it a case that a single is up to the job? Thanks Tim

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I'm not sure, it's probably been nearly ten years since I did anything with an old 12v to be honest and not far off in terms of building a car or engine!

 

What I can say is that these somewhat simple upgrades in an R32 head seem pretty good for this amount of power and these high revs, so.... I'll let you make your own mind up as to how much modifications you need for high hp!

 

https://www.turboimpression.de/ueber-den-zulieferer-6?lang=en

 

 

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