94RHDFD

iTrader: (3)

I'm about to start on my swap and I'm trying to decide if a T72 is enough turbo the 20b, I know that a T66 will run out of UMPH in the higher rpm range and I'm not sure about the T72,and I don't want to go with a T88. What do you guys think?

Looking to make 600 to 650 RWHP @ 12-15 psi on pump gas.

Greg

T72 or 76 would be a great choice, Exhaust sizing is Key with a 20b

87GTR

iTrader: (61)

the 20B car I saw at Amemiya's shop had a T88 on it and made 600 hp on stock ports @ 1bar.
so i can see a T76 at 18psi doing 650HP on a ported motor.

Kurgan

Bigger = Better on a 20B

Kurgan

and turbonetics doesn't have an undived 1.32 housing, neither does Garret.... BLARG!!!!!!!!!!!!!!!

94RHDFD

iTrader: (3)

why do you need a 1.32 undivided exhaust housing, my T72 uses a 1.32 divided exhaust housing

peejay

How are you going to divide 3 rotors' exhaust pulses into a 2-way divided exhaust housing?

(or do you just not care about keeping the pulses divided and just shove everything in to the two divisions?)

Node

iTrader: (1)

is there such thing as a 3 way divided exhaust housing? I'm sure it could be made, but is there one made now?

crispeed

YEH!
It's called using three independent turbos! One per housing!

crispeed
87 Rx-7 TII
9.20@150mph
2600lbs

Kurgan

This may be what I'm doing next year... If I can't get a 1.32 a/r undivided by SOMEONE in a huge turbo... I'm gonna 3 turbo the SOB.... I wonder what would be a good size turbo for that? They would have to be relatively small, I'm thinking something less than a 60-1... can you imagine the Manifold design nightmare under my FC's hood if I do that?

j9fd3s

iTrader: (3)

i was thinking of 2 60-1's it would make the dual exhaust easy, there are 2 oil drains in the block....
of course the stock ones fit the "budget" right now

mike

Kurgan

I was ready to go single turbo, but I can't find the right one... so I'm gonna run the stock twins this year... Why can't they just make a 1.32 undivided!!!!!!!!!!!!

Evil Aviator

Why don' t you just slap the divided housing onto an undivided manifold? Oh well, I think it's better to first get the engine running with the stock turbos anyway.

j9fd3s

iTrader: (3)

its also one less thing to mess with (and spend money on)

mike

4SFED

Myself and a mate are wacking a 20B into a gen 3 and we are using one of the new Garrett dual ballbearing turbos.. the GT42/45. It arrived on our doorstep last week and OMG, it is an absolute monster. it is a .7 front and a 1.5 EX housing, but it is split pulse as well. We couldnt find anything big enouhg that wasnt split pulse. We are just going to round the dividing piece (in the ex housing) off and just pump the 3 pipes into 1 big pipe, then straight into the split ex housing.

We are jst about to start making the ex manifold... which will need a stack of bracing etc as the turbo is around the 13KG mark! Should make some stupid amount of grunt..

Bitchn7

While on the topic of turbos for a 20B. We may have sold our supercharger that we were going to use but isn't suitable for a car that will be used often so are going turbo now.
We are after 5-550HP at around 12-15psi and maybe around 6-650Hp at 18-20psi if possible. These are flywheel figures. This will be in our little 323 hatch.
What do we use?? suggestions.

94RHDFD

iTrader: (3)

For the 5-550 use a T66, for the 6-650 use a T72 or bigger. The T66 and T72 should give you more HP than the numbers you want.

BTW, those are RWHP I listed

peejay

throw three Super 60 T3's (with the biggest exhaust housings possible, I think it's only .82 A/R) on there, one per rotor.

Hey, it might actually work, too. Plumbing nightmare, tho!

Evil Aviator

You should be able to get 550bhp with stock parallel twins running around 15psi and a street port.

Bitchn7

Don't want touse factory twins,pain in the *** and harder to fit in 323. And the ones that are with out engine are poked anyway.
Cheers guys.

1000HP20B

I have used a T72 on two 20Bs we've done and both have worked great, one I have recently changed to a T76 as it had maxed out. I ran a .96 single entry exhaust on one and a rare 1.14 single entry on the other. It's worth noting two things, the T72 compressor wheel is the same as a Cummins diesel 550hp diesel comp wheel, in theory a diesel engine ingests nearly twice the amount of air to make the same power as a petrol engine, so in theory a T72 comp wheel should make near 1000HP, but in reality it will scrape it in at 880HP. Single entry exhaust housings flow considerably more than a divided housing with the same A/R ratio. I'd try to find a .96 for a street car and it will spool up great. Both cars I put these on are drag cars that run powerglide transmissions with trans brake, and when staged with the trans brake on, they reach full boost in 1-1.5 second at wide open throttle before the launch.
Garret GT42 ball bearing 900hp unit would be a great choice too I would think.

94RHDFD

iTrader: (3)

Thanks for the info 1000hp20b, I was really hoping someone who has used the combination before posted

Kurgan

1000hp20b:

So, are you saying that running a GT42 with an undivided housing around .96 would be better than a 1.32 divided housing? Most people tend to think that running a divided housing with an undivided manifold doesn't make THAT much or a difference... but I am stretching for the HP numbers that you are talking about... this is a street car... I am insane.

1000HP20B

Kurgan,
We use 1.32 divided exhaust housings on 13b's and first tried a T72 with .96 single entry exhaust housing on a 20B 2 years ago. Its worth noting that both the T72's Ive fitted have Q trim shafts in them. We ran the engine on an engine dyno as its out of our dragster, then tried a 1.14 single entry exhaust housing, it made only a little more top end power with the change and at that stage we were making near 700hp.
I now have a different combo' but the T72 was great.
I think the 1.32 housing will certainly make boost come on real quick but the exhaust manifold back pressures may go a bit high for some serious power making. Try it and see, I mean second hand exhaust housings are cheap and easy to change.

Greg

If anyone is interested I have a Innovative Turbo Systems GT76 Turbo that I need to get rid of. Its a GT76 (76mm comp wheel) With Qtrim 1.32 Tang Housing. 3.5" Vband flange and exhaust adapter clamp, polished Compressor Housing. Price: $1950


https://www.rx7club.com/forum/showth...threadid=67360