how much boost is the stock turbo good for 88 t2

 

around 10psi effieciantly... S5 turbo is a nice upgrade oyu should look into.. I am glad i made the swap..
Dave

 

what parts do you need for the s5 turbo conversion
turbo, manifold, ecu.
any thing else like injectors or sensors etc?

 

just a S5 turbo and manifold(exhaust manifold that is) you can pick one up for areound $200 shipped... Great bolt on improvement..

 

from ebay or some where else?

 

I think the only thing that increases with the S5 turbo is the wastegate, someone here was saying that the compressor/turbine fins are exactly the same. Does the S5 manifold use a divided housing, or better twin scroll?

thx

 

do you beleve the twin scrole realy ads some sort of improvement. i have long since removed my twin scrole and welded the hole shut

 

so if the s4 and s5 turbos are the same and the only difference is the wast gate then a boost controler would work just as well

 

No, the boost controller adjusts when the wastegate opens. If you have a poorly sized wastegate (stock s4) and a high flow exhaust, you will experience overboost even when the wastegate is fully open.

Twin scroll is a really really neat thing by mazda. Just like the the 6port intake system of the NA, the twinscroll has a similar effect. Better low end performance.
With the twin scroll on, you get a really fast spool time becuase the exhaust gases are sort of choked off into a more powerfull stream to push the turbine. The faster spool time means more power at lower RPMs. As rpms increase the twin scroll flapper opens fully and gives you a faster spool becuase now more exhaust gases can push the turbine.
Having a functional one is the best way. Removing it will not give you much of a noticable high end HP increase, as the flapper when open doesnt restrict flow that much.

 

well if th eboost controler adjusts when the waste gate opens you could use the BC to mimmic the s5 turbos waste gate. as i understand it a boost controler will only increase the boost level past the waste gate pre determend opening point not lower it, so in theory a boost controler is all you need t produce the s5 amount of boost.???????????

 

yes and no.. a S5 turbo is more effieciant around 12-13psi and a S4 is off around 10psi.. the S5 turbo has a better waste gate design so you dont have any boost spikes(over boost the turbo).. Theoretically all the boost controller does is fake out the waste gate so to say.. this keeps it closed longer b4 it starts bleeding off exhaust gas.. like say b4 your boost controller you can only see 9psi of boost.. well with the boost controller cuts the amount of pressure(boost) sent to the waste gate hose so you can hit say 12-13psi but the waste gate still only thinks its getting 9psi(because thats all the boost controller is letting it see).. you understand what i am getting at??
Dave

 

Yea your right, I thought you meant that the boost controller controlls how far the wastegate opens, wich is totally wrong.

Just keep in mind that at 10psi with the S4 turbo (stock) and a high flow exhaust it won't stop, it'll keep going up.

 

any one have a s5 turbo and manifold for sale or know where to get one ?????
e mail me at rpmturbo1@hotmail.com

 

there is a couple here on the forum in the forsale section that arent priced to badly..
Dave

 

Reminds me of how I should have went for the S5 turbo. Hopefully I can find a machine shop that can port the hell out of mine

 

I'll have a hybrid for sale shortly for 325 bucks shipped. its an s4 turbo with a to4b wheel and stock housing. I also got the wastegate ported by a machine shop so there is virtually no boost creep or spike and the s4 flapper has been taken out and the hole plugged. This thing pulls crazy at 15psi. Pm me if your interested.