We have moved on to the .82 housing Clive. Initial tests on a back to back basis were a little disappointing, with a 500rpm increase in lag (To be expected of course) but no noticable increase in power. Following further mapping we did liberate a further 10hp, again disappointing and possibly pointing to a restriction somewhere else.

Further testing at a lower boost level proved this to be the case. At 1.5 bar we have gained 40+hp when compared to the original 35R. But the increases seem to get lower as the boost is raised. We suspect this may be due to the stock heads and cams and are pushing ahead with CNC ported heads, Cosworth + 1mm inlet and exhaust valves, uprated springs and retainers and Cosworth 278/274 cams. This combination has worked well in the past so we look forward to releasing the results when the work is complete.

Martyn

 

Why would you expect more lag from a billet wheel - I would have thought it span up more quickly, so spool would be quicker, and boost threshold lower?

Or, to put it another way, what are the actual pros and cons of billet wheels?

 

For two reasons in this case, the comp wheel is larger even though it is lighter and the exhaust housing is larger as mentioned.

 

.82 ar vs .63

not to do with the billet wheel but larger housing. Atleast AFAIK.

 

oh..oops...guilty of not reading carefully enough

But, nevertheless, what are the pros and cons of a billet wheel?

 

Dont think there are any cons!!!

 

Hi,

read the first few pages of this thread, its all explained there, and whats more Garratt have just released their Billet range, must be plenty of positive reasons why.

Also as Garratt dealers we will be releasing back to back testing and costings, soon.

We can now also offer a billetizing service for the MD range of turbo's, if you would like to know more about this service it will be announced in the next few days on our web site.

cheers
Kev

 

hope their paying you guys royalty for all your donkey work

 

Just had a billet GT30 put on my 2.35 with standard sti 8 heads here is the result
Mapped by jolly green monster and built by mike latimer
Will be changing cams soon which should see up to 10% extra

 

Hi,

well done fellas, top result.

We have found the same as Martyn Jefferies has found and indeed your car, CJ, as in the graphs above, cams are very important, especially at the top end, look at Martyns figures, 40 bhp gain at the lower end of the rev range yet no gains at the top, in fact the more boost added the worse the figures become and its all down to the heads and cams, if the engine cannot breath at the top it wont make the power.

Look forward to seeing the result after cams on both the cars mentioned.

Cheers
Kev

 

what cams will be used?

 

Impressive results, those v-power or meth mix? 0.63 or .82 housing?

 

still thinkig about cams and results on v power & 15% meth on a .63 housing

 

what are the options?

 

Martyn, have you tried the 33 billet yet??

 

Engine for that one being built at the moment Ken.

 

Kev, got an MD321V here crying out for a billet wheel. Price and timescale for the conversion please?

 

Hi,

its £350.00 + vat, timescale 3 to 4 weeks turnaround.

Remember though we are coming to silly season regarding actual working days.

cheers
Kev

 

Yuu actually give yourself time off at Christmas Kev !

 

Nope, its the postal service that wont be working.

cheers
Kev

 

lol, for a moment I thought the earth had stop spinnng with you actually taking time off

 

Hi Clive,

got your light weight windows here, forgot to let you know,

Cheers
Kev

 

Hi been following thread with interest. Great thread. Well done kev n the lads.

What's the downside of running meth (if any)?
I've got simtek so can have a meth mix map, But internals are straight sti.
Sti V4 rods n pistons, Sti cross drilled and nitrided crank, ACL race bearings, semi closed block, FMIC, 500cc injectors with billet hi flow rails, walbro 255, full decat, cold air feed intake kit.
I have the SC36 billet with 10/15% meth in mind.
Is this safe with these internals?
What hp spool might i expect?

Car use - fast road, sprint, hillclimb.

cheers, keep it up
chas

 

Hi,

the set up you have engine wise is fine, the STI's had forged pistons as standard, with the upgrades you have got it is a fairly strong set up and will work well with the SC36 Billet.

The down side to methonol is its very corrosive and does attack certain types of fuel hose, as long as these are swapped out for better quality stuff there should be no problems so long as its kept in air tight containers and used within a certain time as it does take on water, the term being hygroscopic.

Spool will be good, BHP should be around 360 bhp on "V" power, more on a 20% meth mix but remember the limitations of the top mount intercooler and the gearbox.

Thanks for taking an interest in this thread.

cheers
Kev

 

Hi Kev
thanks for reply, I already have big FMIC which when we mapped at the Mintex test track was only showing 2.5deg C increase in intake temp no matter how hard we pushed (august mapping) so would the 500 injectors push any more than 360 on meth and if i bought the 210l drum is that air tight enough for it to keep for regular mixes?
Finally would there be any advantage of going to the SC38 billet.

I'll be buying one or the other!!!

cheers
Chas

 

Hi,

the 500 cc injectors are good for about 380 BHP max.

We did a 2.1 stroker with a meth mix and a 36 Billet, here is the result.





Its a result that shows the turbo is capable of flowing plenty of air, and again raises the argument that supporting mods, cams, inlets and exhausts are very important to the final result, this one worked well.

The SC38 Billet is also a very good unit and will do you a great job but the gearbox will need addressing.

Cheers
Kev

 

At 400lb/ft of torque you will also be pretty much on the limit of the classic rods

 

Hi Banny,

yes good point, maybe its a 36 Billet for Chash.

Cheers
Kev

 

Hi,

just had a nice result on an SC36 Billet.





Power at the wheels, AFR and boost.





Car is an STI 8 running stock ecu mapped by Pat, mods are simple, just the SC36 Billet an inlet pipe and a decent 3" stainless exhaust.

spool results from road test just in.............

1 bar of boost @ 2771 RPM

1.5 bar of boost @ 2871 RPM

Result.

Cheers
Kev