Iain im running 412bhp on a 20g on newage wrx heads. Unless your thinking of higher figures in the future and have funds for the heads now, i dont think its worth it

agreed..

did a car running 420bhp on 99uk heads, redid it last week with the only change was sti 5 heads and it made 470bhp.. the engine just felt so much less restricted and sounded so much better and was happy to push it further.

Simon

50bhp from new heads .. wow! that would destroy my engine for sure then ... lol

Looking for 380ish then until I can go forged. thanks for the help guys :thumb:

lol

I wouldn't pull a wrx engine and fit sti heads if you are aiming for 380bhp.

do it when you forge it.

Simon

Buying the heads, taking the engine in and out, cylinder head gaskets, even if you do it yourself it is a full days work and a fair bit of expense for the heads by the time you have them ready to go on the car, having checked compression ratios etc.
As Simon says, if you are happy to stop with the maximum you can get out of a WRX set of heads before you go forged internals just stick with the WRX heads.
Can I also point out that there are so many different turbos out there that you need to be very careful and stick to turbos that are known to perform well. There are TD05 20G, TD05-06 20G which is what Stuart has, and TD06 20G. These three turbos from the same manufacturer / assmebler etc. will vary in spool and ultimate power output so if you are buying one of these turbos take extreme care and it can be a bit like a pig in a poke if you buy a second hand one unless you clearly know what it is .

http://i45.tinypic.com/2v85w7l.jpg

http://i46.tinypic.com/2ykal5f.jpg

http://i50.tinypic.com/21nponp.jpg

These graphs are from a TTS rolling road day with Steve Simpson at TEG Sport. The car is Darren's P1 in 2.5 litre format with TD05-06 20G. Fuel is V-Power plus 1ml per litre NF mapped by Bob Rawle on a Simtek. The car was previously in 2 litre format but we didn't get a rolling road graph prior to the 2.5 engine build (brought on by a failed bottom end). The car was quite laggy as a 2 litre but an absolute stunner as a 2.5 litre. As most of you will realise the boost graph on the rollers does not represent the early and ferocious spool available on the open road.

Now adding on from that, typically another one of my turbos, TD05 20G will do 380 bhp perhaps 390 bhp and I never claim any more but a guy in Ireland has recently e-mailed to say 407 bhp on their road fuel plus NF.
Similarly I say my 18Gs are 360 bhp but there are quite a few close to 380 bhp.
Choose carefully because if you are chasing numbers you could be very disappointed when you do not hit the figure you are expecting. Get something that is tried, tested and consistently cuts the mustard but also remember that figures on one dyno may have little bearing on the figures from another dyno.

Is there any way of spotting the difference externally between each type?
If a s/hand turbo was offered as one of the variants, how would you ever know?

You can only identify by experience from looking at them and may need to check out dimensionally unless they are stamped etc.

:thumb: As I was suspecting.
So can I generalise that a TD05-20g is 7cm2, a TD05-06/20g is 8cm2 and the TD06-20g is 8cm2 but with a larger compressor housing?

Absolutely not at all. We build TD05 variants with 7 and 8cm housings.
The art is matching the turbo spec to the application or settling on a spec that will deal with a wide range of requirements.

hi the car in question above which is a classic made 406.9bhp / 370lbft @1-6 bar boost on one of harveys td05 20g turbos. Engine is a fully forged 2.ltr with all supporting mods. cheers harvey :thumb:. I still have that smile on my face when i drive it that i told you about in email . :D

Your feedback was much appreciated, especially after the "local" difficulties and the result is a credit to you and those involed.

Understand the concept of housings, impellers, ball bearings intake dia etc,still trying to understand how rally cars turn out 300hp/450ftlb torque on restricted intake

Rally cars and how much they can get so much torque.......AFAIK it's all down to how much you can compress the charge and ignite it ......!

Take a small amount of charge and compress it at 3 bar and over and that's a lot of fuel and air ready to burn in a 2 litre engine :)

you just need to build a bullet proof engine and have a very sophisticated ECU to manage each cylinder :)

Shaun

Exactly.

In a word..............boost.

So the bottom line is the touque can be improved by pumping air and fuel in until the charge temp becomes to hot then detonates,so most aftermath turbos are a compromise?

So supercharging its volume/pressure from low rpm,turbos use pressure/volume from higher rpm.So effectively you could put larger compressor impeller and housing but would be laggy until engine produces enough exhaust flow to spin up?

but the fueling has to be at the right and varying ratio across the operating range.
Certainly a compromise between compressor size and spool and optimum exhaust size, and wheel size etc etc.

Can anyone advise me on the correct actuator to use or buy on a td06 20g on a 02 newage wrx?

I have a friend who has just put a td06 20g on and it couldn't be mapped as the old actuator off the td04 couldn't handle the boost. The only problem now though is that the actuator he got hold of is over-rated(30psi). The car could be mapped with this actuator on but it had to be adjusted manually to be fully open so that the wastegate is pulled open before the turbo even kicks in. This is to stop it over boosting when it does kick in. The turbo is now really laggy and coming in real late.

The turbo has its best pull at 5000rpm and before you know it your hitting the red line. It's also only running about 290bhp with front mount,600 or 650cc inj(not sure but are bigger) and de-cat. But to be honest, my wrx is running 280bhp and his feels brutal at 5000rpm compared to mine.

So what actuator would need to be bought to get everything set up right?? Also is there anything else that could make it a better like a 3 port boost selenoid to get the over all balance right?

Cheers

Mark

Prob a Forge TD05 replacement actuator (I don't think they do "TD06" ones, as such?)... But with something like a 17-22psi spring in (maybe even a higher rated one, if running 30psi(!) target boost?)?

Check out Forge's website and eBay...

He doesn't want to run 30psi LOL. He said the actuator currently on the car was rated at 30psi or something, and this was too high to get the boost set up right via the remap. We can't find a actuator that is listed for the tdo6 20g. Like you say, it seems there isn't one made for it.

So running this turbo at a 'normal boost setting' would require a td05 actuator with a 17-22psi spring?

Ignore that 17-22 rating - I just plucked that (wrongly) out of the air. Sorry.


I intend to fit a TD05H 20g, prob running <=1.5bar (22psi) - I assume so, anyway! - and API Dave suggested an act. spring rated at 15-18psi.

So by that rationale, if you get a spring rated at between c.7 to 4psi lower than the intended target boost, you'll be in the right sort of area.

I get you mate. So ideally we need to go to the mapper and ask him what sort of boost he intends to map it to, taking into consideration what mods have been done. Then get a td05 actuator that is rated a bit below the intended boost level.

Cheers for the help

Mark

Yes. You won't go wrong if you tell your mapper the mods.

Then he'll know the amount of boost he'll want to run and can advise accordingly on act. spring rating (and actuator itself, if actually needed). :)

FAO JGM, so to be clear simon, i have pmd you before over this and i am swung between overall cost and visible performance gains. ( not meant as a discredit to any info sent btw). if i have a 06 sti VF43 as i believe, a md321t on standard internals would underperform, as it would not be able to "stretch its legs", the md321h would be more suited on standard internals compared to the 321t, but what about compared to the vf43? i would be prepared to sacrifice top end over improved accelaration btw. just want to be scared of my cars potential again. many thanks, sorry to be a indecisive pain in the arse. lol.

Mark : For your application a 1 bar actuator will be about right for your setup. If I was fitting this I would use a Mitivac to adjust the setting to get it right.
Greg : The advantage of a Supercharger is low down boost as it is usually engine belt driven and geared to provide boost as low as 1000 rpm if you wish. However, it only has about 50% efficiency whereas a Turbo Charger may not have a boost threshold until 2000 or 2500 rpm but it is something like 75% efficient. The only Superchargers I have experience with are for low pressure applications ie. 6 - 14 psi as opposed to Turbo Chargers up to 28 psi.