What turbo shall I get

[skiddusmarkus]

Quote: Originally posted by Essex_Lad on 23 May 2004


on a T3 wont a rollerbearing one help it speed up quicker meanin less lag? and then u can run more boost?

Al

Yes but will also double the price of it.Think around the £1k+ mark,A smaller turbo doesnt need the RB core to get quicker spoolup but if it has it then all the better.An S14A T28 would be good for a 2l conversion as they have a relatively small A/R(0.64 I think) and RB vore as standard.Theyre not too expensive new-around £750.

Its not just a case of slapping on any old turbo and hoping for the best,you have to give it a lot of consideration and the cams play a big part in turbo choice too.

 

[Mike@Rentech]

So is my one no good?

 

[skiddusmarkus]

I cant tell from that picture-whats it off and what model is it?The A/R seems ok to me for a low boosting car with good driveability but for higher boost would be useless-the turbine would be very restrictive and cause a lot of backpressure,robbing you of power and not holding boost.

A good way to reduce backpressure and get good gains in power and spoolup is when you have your turbo elbow/downpipe fabricated,get a twin dump off the turbo ie a small pipe-say 1" for the wastegate and a larger one-say 1.5-2" for the turbine,with them joining back up around 12-18"(less is ok if space is an issue)further down the downpipe.This lets the gases flow out better from the turbo.You can even have the wasteagte pipe venting underneath the car with a longer pipe(screamer)if you want to scare the neighbours.

 

[R1916V]

Looks like a GT-17
Ive got at GT-22BB for sale (but its rather expensive). It was for my Valver project, but im going for a GT28BB when the time comes...

In my eyes the turbo is to little. What AR is inlet/outlet? If you should get best spoolup youd need a ballbearing turbo with rather large AR outlet... og midsize inlet. Would give highflow even at low revs. And the ballbearing ones would hold preassure up to 7000-8000 rev.

 

[MaLicE]

if u want a custom turbo i know people on rtoc that can get them made to your specs, quiete a few people on there are running some t25s with cutback blades and 360degree bearing, can get that spec for 350 quid i think it is!

also if u had gone and used a gtt fitment u could of then looked at skyline turbos as they are the same fitment, can get t3s in the us or jap for a r33 for about 300 quid ...

skid surely u cant fit a screamer pipe without an external wastgate ??

 

[Master Chief]

Hi all.

I am also starting a turbo project on my 172.

Basicly i bought a while back , from mailto:M@thew">M@thew, all the parts that are used on the Megane 225.

The intake and outlet manifolds and the turbo.

Although i am not sore what size is it exaclty , it is designated a Mitshubishi TD04-10.

From my reseach this equals to about the Geretts T28s.

Although Renault are using this on the Megan and other 2.0L Turbo engiens who have lower CR , i think it would work fine on the standart 172 1:11 CR.

I dont think though , that anything ove 5-7 PSI of boost, on the original CR would be safe, even with an intercooler.



Anyway, what are you going to do reguarding engine managment ?

 

[Fred@BTM]

You mean this turbo Master Chief???

http://erc.qmuc.ac.uk/cliosport/gallery/full/1085365000__turbo1.jpg

BTW if the parts you bought off mailto:M@thew">M@thew originally came from Captain Slarty, then im afraid theyre not Megane RS parts, similar, but different!!! They are infact Vel Satis parts. The Manifolds are both larger bore on the megane (i think) and the turbo is defo larger on the RS compared to the one i have (above in pic)

BTW i now have Captains ENTIRE collection of parts, if you need anything, let me know, i have turbo pistons, cams etc etc!!!! (about £5Ks worth of parts!!!)

 

[viceroy]

I wouldnt have thought it possible to turbo a 172 without dropping the compression???

 

[stan*]

11:1 is 2 high 2 run any usable boost

 

[viceroy]

So what you guys gonna do to lower the compression? build up the head? get different lower CR pistons, if so what pistons would you use?, or grind down the std 172 pistons to the required CR?

 

[stan*]

drill a hole in the pistons !!

it all depends how much boost and therefore power u want (also how much cash u have!!)

thicker head gasket--low boost--moderate power gains--cheap..ish

skimmed pistons--bit more boost--bit more power--bit more money

forged pistons+internal work--high boost--lots of power--lots of money

 

[Fred@BTM]

The engines im using are already low comp, i think theyre 8.6:1 IIRC

plus my engines have much stronger cranks and blocks, different head (no VVT)

youd be surprised by the difference in crank between the 172 and turbo!!!

 

[Fred@BTM]

Quote: Originally posted by haitch on 22 May 2004

hey fred is ur conversion finished? u doin it urself? booked in at GDI for head n cams etc then its prob tbs for me but not fully decided so any info on conversions apart from k-tec is helpful

na mate, just getting started!! i think im gonna have a crack at doing it, but if not, mr GDI will be getting a phone call!! i have SO many parts you wouldnt believe!!!!

 

[skiddusmarkus]

I didnt realsie the CR was 11:1.Im raising mine to 8.7:1 and getting funny looks from other GTiR owners.You definitely dont want to run much boost without at least a very good intercooler and a decent ECU controlling it all.

If you want to lower the CR then the easiest way is to use a thicker headgasket.

 

[Fred@BTM]

christ your raising the CR to 8.7:1, what is the std CR on the Pulsar??

 

[turbo man]

I have a T25 on my Clio 16v turbo. It runs 7.5:1 cr with uprated everything. It wont hold 1 bar of boost. It tails off at 5000 rpm. I would go for a T28.

 

[skiddusmarkus]

Quote: Originally posted by Fred2001Dynamic on 24 May 2004


christ your raising the CR to 8.7:1, what is the std CR on the Pulsar??

8.5:1-not a big increase but enough to reduce lag a couple of hundred rpm.Rest of engine is being well modified to take up to 2bar.

 

[skiddusmarkus]

Quote: Originally posted by turbo man on 24 May 2004

I have a T25 on my Clio 16v turbo. It runs 7.5:1 cr with uprated everything. It wont hold 1 bar of boost. It tails off at 5000 rpm. I would go for a T28.

His CR is way higher than 7.5:1 though.Running 1 bar on 11:1 would lunch the engine as it would detonate badly unless run on proper race fuel with a fully mappable ECU.

Benefit of higher CR though will be more torque off boost,less need to rev to get power and better mpg than a low CR engine.Downside is it doesnt have the same power potential and reliability.

 

[haitch]

ta for the reply fred , keep us posted