mef

I've machined my TD05 housing ready for fitting a new inlet tube but as it's for my rally car I have to install a 34mm restrictor in this tube.

I may as well machine the tube to include the 34mm section, the thing is, does anyone know the exact details. I understand that the 34mm section has to be a maximum of 50mm from the turbine blades and that the parallel 34mm section has to be a certain minimum length (but what length is this?) I think there might be a spec + drawing in the "FIA yellow book"

Also what angle is best from the 34mm section to the 47mm diameter of the turbine aperture? ie. a steep angle then parallel at 47mm or tapered all the way from 34 to 47 where I have counterbored the housing right up to the 47mm section that was factory machined?

Any help would be appreciated,

Thanks,

Martin

[Edited by mef - 1/7/2004 10:53:00 AM]

David_Wallis

give howard at www.hdcsubaru.com a ring, tell him I suggested you ask him..

he uses them on his rallycars.. so will know..

David

mark@wrx

We got a 32mm restrictor from Townend Garage for my mates Group N Impreza. I think that the ideal length of the restrictor is 4 times the minimum diameter to reduce inlet turbulence, i.e 34mm * 4= 136mm. We had to alter the hard inlet pipe that is located under the inlet manifold to get a good fit.

mef

OK Mark, yes, I got the restrictor for my VF24 from there, it just slips on the front of the normal inlet pipe and is attached by 2 capscrews & locknuts. I fitted the Prodrive GpN silicon hose in place of the crappy OE one. I had to re-route the fuel pipes etc and turn the turbo mounting a few degrees to get it through. Now I intend to fit the TD05 and the nodification to convert to straight entry will encompass the restrictor, hence my questions regarding the dimensions.

I've since found the FIA website with the specific rules and dimensions so I know know whats required legally, it's now just the taper angles I need some info on,

Thanks,

martin

greasemonkey

Silly question, but are you running in a homologated championship, or is the car going to be running in Group B Martin?

[Edited by greasemonkey - 1/7/2004 5:02:09 PM]

mef

NO, not with a 34mm restrictor! My car is well away from GpN but by no means GpA!

It's the taper on the back of the restrictor, towards the turbine I'm concerned about, not sure if a shallow angle all the way to the turbine aperture or a steep angle into a parallel section the same diameter as the turbine aperture would work best. Possibly the latter as surely it would be best to allow the air to expand as it goes towards the turbine?

Any offers?

greasemonkey

Lol! Yeah, just realised I'd tripped myself up over the restrictor diameters there, as edited post shows!

Only thing that worried me is the possibility of someone protesting your car on the basis of it having a non-homologated turbo in it. Not an issue if you're running in an open/Group B class, but the last thing you want is getting disqualified when someone you've beaten takes a close look under your bonnet!

mef

Not a problem, for the events I do I'll be running in GpB or class B12 as it is.

greasemonkey

Cool, no problems there then. Think you'll find your car runs in B13, not B12 though!

mef

Correct, B13, sorry!

EMS

I thought the TD05 is homologated on the GC8? I also thought the regulations enable you to modify the compressor housing to fit a restrictor............

Mark.

mef

I looked at the FIA regs today and modification to the compressor housing is allowed to fit the restrictor. Wether or not the TD05 is actually homologated in GpA I don't know. I was considering doing the "24 Heurs de Ypres" rally this year and would have to enter in GpA as an homologated car, don't know if I will get away with that, can't see it being a problem, they like foreign clubmen entering these events anyway and as I'm not likely to be contesting any champoinships or even stealing any class pointsI think I might get away with it! Just want to go and do it for the crack!

Martin

EMS

Martin,

At the technical control, only the restrictor diameter and fitting of the restictor will be checked. I doubt if they will check the make and type of the turbo. This is only the case when your car is checked after the event.

The TD05 IS in the homologation of the GC8 Impreza! However, I am not sure my interpretation of the rules will be accepted..... It´s unclear to me if you can mix up the different homologated parts.

Mark.

mark@wrx

I wondered about the mixing of homologated parts as well. I wondered if there is any advantage to be gained from fitting the equal length manifold from the JDM STi8 to a an STi6.

EMS

Mark,

If you want to do that you are not mixing homologated parts, but parts that are homologated to different cars! New age and classic......

How about a Citroen WRC engine in a GC8 Impreza for group N?

Mark.

mef

Looked at may restrictors at the Autsports show today and it seems like I've found the answer to my query, the section between the 34mm bit and the turbine blades should be a long gradual taper between the two diameters. Found "Owen Developments" particularly helpful with this, they had many examples of modified turbos and restrictors and that was how there's were made so I'll do mine the same.