Grimlock

you know that a/r mumbo jumbo. exhaust side and intake?

any of you guys know????

if i remember correctly i read somewhere that the stock 88TII has a .88 exhaust side but whats the intake side?

also the i read that the exhaust side of the 89 and up TII is 1.00, is this right guys? did the intake side increase as well? and what size is it?

thanks for respsonses in advance....

Grimlock

anyone......some here has to know.

darkwaveboi

i hear ya..i just dont know either...

Henrik

I believe you're correct on the exhaust housings. The compressor is the same for both turbos.

Henrik
87TII

Scott 89t2

I doubt the exhaust is 1.00 considering a full T04 is .96

lets just say they are too small for anything but stock boost levels

Henrik

Excerpt from "http://www.hitman.hm/13BHints.htm"

The Series 5 received lighter rotors with a higher compression ratio , and hence different counter-balance weights. The Series 5 also runs a larger turbo with dual wastegate flaps. It has a 1.0 A/R exhaust housing where-as the Series 4 has a 0.88 A/R. Compressors are very similar. Physically if you put the two next to each other the Series 4 has a flat-ish look to the exhaust housing , the Series 5 has a more bulbous look.

Henrik
87TII

Chris Ng

Here's what Jack k. Yamaguchi has to say about the series 4 turbo:

"The twin scroll turbocharger concept was developed jointly by Mazda's Department Five and Hitachi, and is manufactured by Hitachi having been designated HT18S-2S. It's turbine-side bearing area is now water-cooled, and the main body is further protected from high temperatures by a dual-skinheat shield. The 1 blade turbine, of impact design, is 64 mm (2.52 inch) in diameter. It's scroll area, the nry path for exhaust gas, is divided into two passages seperated by an integrally cas wall;one, called the secondary scroll, has a trap-door-like gate operated by intake vacum.
The turbine thus has two cross sectional area (a) factors, A being the scroll's smallest area as used in calculating turbocharger performance characteristics: 6.00 sq. cm (0.93 sq. in) forthe primary path and 9.48 sq cm (1.47 sq. in) for the secondary. The other factor is R, the distance between the turbine-shaft center and the center of area A: 59.4mm (2.34 in.) for the primary path, 60.4 mm (2.38 in.) for the secondary. Thus the twin-scroll turbocharger has two A/R ratios: 0.4 for the primary path and 1.0 for the primary and secondary combined."

as for the compressor side, "It's 12-blade compressor is 63 mm (2.48 in) in diameter"

so there you have it.. the turbine for all purposes has a 1.0 A/R .. .Note, jsut because a turbine housing is larger doesn't mean it's going to have a higher A/R (ie: TO4)

HWO

a/r ratio numbers can only be compared from one exhuast housing family to the other. ie: a T04 0.96A/R exhuast housing is a lot larger and therefore flows more than a T3 0.96A/R exhuast housing would (if there is such a thing)

A/R ratio is just the ratio you get when you divided the area of in the intake over the area of the turbine wheel, or something like that, as explain by the guy just above me

Grimlock

thanks bro, thats some good info....i have the stock 88 turbo on now and i am about to switch to a 90 gtx turbo. i guess i should check to see if that vacumm activated door is working on my turbo. what are the symptoms of it not working????

do you get low end boost and no high end or vise versa

RETed

I hope you're swapping turbo exhaust manifold also, because it's going to take a lot of mods to make the turbo fit.

The turbos are, for all intent and purposes, identical in size.&nbsp The advantage of the Kouki turbo is that it runs a true divided system from turbo exhaust manifold to turbine housing - this gives you a much broader (earlier) powerband versus the older Zenki turbos.



-Ted

Chris Ng

The series 5 turbos don't have the flapper door on them..
If you are going to purchase a series 5 turbo, you're also going to have to purchase the manifold for it.. it won't bolt diretly up to the stock series 4 manifold without some work (like Ted mentioned) and you won't notie any benifit if you don't switch manifolds either..