This week in the shop… BA8 Prelude Turbo

OriginallyPosted: October 10, 2010

Hi all,
First off I must apologise for the lack of updates but I was a little bit poorly. A chronic attack of the deadly man-flu. Oh it was terrible I was up nights looking for people to show me some sympathy, but all I got was people giving out to me for moaning.

Anyhoo back to the Prelude. The owner asked us if we could do a few bits and pieces to the car mainly a turbo conversion and in our usual Bob the Builder fashion we said “Yes we can”. It been an interesting project that’s been with us for a while and has evolved along the way and has finally reached the mock up stage.

Okay so what do you need to do to make a normally aspirated engine into a turbo one? Slap on a turbo I hear some people say, well yes obviously but if you do just that things kinda go like a bowl of rice krispies (mmm) snap, crackle and pop. So first you’ll need lower compression pistons and depending on the strenght of the standard rods, new conrods as well. Here’s where this project evolves. We need new parts already and a certain amount of work has to be done like facing the cylinders so what happens if we go a little bit further. So after a bit of discussion it was decided to get a stroker crank, bore the cylinders and sleeve the block. So what do we end up with, now instead of a 2.2l NA engine we have a 2.5l with 8.5:1 compression using Darton sleeves, Brian Crower rods and CP pistons.

Now for the fun part this 4th gen Prelude is the BA8 with the F22B non V-tec engine which was only ever sold in Japan and as such there are no off the shelf aftermarket parts available for a turbo conversion. What do you do? In our case we have a special box kept secretly in the dark recesses of the workshop which holds (when exposed to moonlight) our welding midget. So if you catch him just right by the ankles he’ll make up a custom manifold for the HKS GT2835 turbo and a full WCP 3 inch stainless exhaust system (ooh shiney).

So now we have a turbo and larger displacement which equals more power, more torques (as Clarkson says), more air and the down side more heat. This is where the supporting mods come in. For the power and torque increase we’ve installed an OS Giken twin plate clutch and a Quaife ATB diff to transfer the power to the ground. To look after the air we’ve fitted a Forge Motorsport intercooler with more custom piping from the welding midget. For the heat we’ve got a 50mm alloy rad and a made to order Mocal oil cooler which is suitably sized to look after the extra heat from the added turbo oil feed which has been tapped in.

All in all a good fun project with a customer whose was willing and insistent on going just that little bit better than the norm. Looking forward to seeing this project completed and will fire up a quick update when it’s done.

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