Twin GT35r turbo kit for fd
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the mazda zoom zoom store
Joined: Feb 2001
Posts: 749
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From: Columbus, Oh
Twin GT35r turbo kit for fd
Hi! This is zavier from rx7 store, I'm thinking about building a twin 35r tubo kit. I would like to know if their is anyone interested in this kit being made.
ive bought multiple items from the store, this just might be yet another investement in the never ending money we all have in our 7's.
price is an important factor. let us know
price is an important factor. let us know
Joined: Oct 2001
Posts: 6,279
Likes: 728
From: Florence, Alabama
a single GT42 '02 makes 102 lbs/min of air... around 800 rwhp on a 13b
a single GT42 '94 makes 84 lbs/min of air... around 650 rwhp on a 13b
a single GT35R makes 63 lbs/min of air... around 500 rwhp on a 13b
two GT35Rs make 126 lbs/min of air... around 1000 rwhp on a 13b.
the penalty for increased airflow is lack of hp in the normal rpm band, 2000-7000.
a typical GT35R makes 200 rwhp at 4000 rpm while a GT42 makes 200 around 4750 on a 13b.
if you are only interested in hp from 7000 to 11,000 twin GT35Rs might be your ticket.
having run a twin Garrett turbo system of my own design and build for the last 5 years and 17,000 miles, and having tested 5 iterations of turbo sizing i suggest you consider turbos w deliverability (each) in the low 40 pounds per minute range.
advantages i have found to date versus a GT42 are quicker spool (200 rwhp at 4150 rpm) and more ponies at lower boost. i will be on the dyno w a new motor with much better porting in a week and expect to make 630 rwhp (80 lbs/min) at 27 psi.
further as to packaging... you really don't want external wastegates as the space for two turbos w all the plumbing is challenging enough. you want internal wastegates, 5 bolt rears w ATP's fabulous "Ultimate Wastegate."
here's what i run and how it compares w various options:
..............................average cold side area..................................avg hotside area
GT35R.........................6.35 sq inches............................................ ........7.07
2 GT35Rs.....................12.70.................. ..............................................14.1 4
GT42 102......................8.39..................... .............................................7.54
GT42 94........................8.17.................... ..............................................7.54
HC Twins......................10..................... ................................................10 .8
as you can see, twin GT35Rs are almost 50% larger in compressor area than the gigantic GT42 102! unless you only care about north of 7000 rpm you will not be a happy camper.
one major advantage of twins is the huge increase in hotside turbine area. this is very important for the rotary. my exhaust backpressure (pre-turbine) is 21 psi at 20 psi boost! this is literally F1 territory when they ran turbos. it also explains why my EGTs (1550 preturbo) do not march higher w RPM. it further supports the fact that when i recently took my motor apart for inspection there was almost no measureable wear on the apex seals and side seal clearances in 4 years.
i like twins and would do them again. i am not knocking the RX7store here but do suggest they give additional thought to sizing twins.
my setup is:
TO4E 46 trim compressors (42 lbs/min)
journal bearing water cooled 360 thrust CHRA
T3 .82 A/R rears w Stage 5 turbines
5 bolt rears
ATP Ultimate Wastegates w 3 inch V band
AGP Billet 15 pound spring modular actuators
two 3 inch downpipes
Burns Stainless 2 into one slip fit/3 inch Vee band rear
love it.
howard coleman
a single GT42 '94 makes 84 lbs/min of air... around 650 rwhp on a 13b
a single GT35R makes 63 lbs/min of air... around 500 rwhp on a 13b
two GT35Rs make 126 lbs/min of air... around 1000 rwhp on a 13b.
the penalty for increased airflow is lack of hp in the normal rpm band, 2000-7000.
a typical GT35R makes 200 rwhp at 4000 rpm while a GT42 makes 200 around 4750 on a 13b.
if you are only interested in hp from 7000 to 11,000 twin GT35Rs might be your ticket.
having run a twin Garrett turbo system of my own design and build for the last 5 years and 17,000 miles, and having tested 5 iterations of turbo sizing i suggest you consider turbos w deliverability (each) in the low 40 pounds per minute range.
advantages i have found to date versus a GT42 are quicker spool (200 rwhp at 4150 rpm) and more ponies at lower boost. i will be on the dyno w a new motor with much better porting in a week and expect to make 630 rwhp (80 lbs/min) at 27 psi.
further as to packaging... you really don't want external wastegates as the space for two turbos w all the plumbing is challenging enough. you want internal wastegates, 5 bolt rears w ATP's fabulous "Ultimate Wastegate."
here's what i run and how it compares w various options:
..............................average cold side area..................................avg hotside area
GT35R.........................6.35 sq inches............................................ ........7.07
2 GT35Rs.....................12.70.................. ..............................................14.1 4
GT42 102......................8.39..................... .............................................7.54
GT42 94........................8.17.................... ..............................................7.54
HC Twins......................10..................... ................................................10 .8
as you can see, twin GT35Rs are almost 50% larger in compressor area than the gigantic GT42 102! unless you only care about north of 7000 rpm you will not be a happy camper.
one major advantage of twins is the huge increase in hotside turbine area. this is very important for the rotary. my exhaust backpressure (pre-turbine) is 21 psi at 20 psi boost! this is literally F1 territory when they ran turbos. it also explains why my EGTs (1550 preturbo) do not march higher w RPM. it further supports the fact that when i recently took my motor apart for inspection there was almost no measureable wear on the apex seals and side seal clearances in 4 years.
i like twins and would do them again. i am not knocking the RX7store here but do suggest they give additional thought to sizing twins.
my setup is:
TO4E 46 trim compressors (42 lbs/min)
journal bearing water cooled 360 thrust CHRA
T3 .82 A/R rears w Stage 5 turbines
5 bolt rears
ATP Ultimate Wastegates w 3 inch V band
AGP Billet 15 pound spring modular actuators
two 3 inch downpipes
Burns Stainless 2 into one slip fit/3 inch Vee band rear
love it.
howard coleman
Mmmmm.... Howard always up with the research and good info.
Was thinking that with the GT35, hey would be small enough and with its quick spool, would give good low-mid power and peak power ofc.
I'm not a expert in any way on turbo specs and etcs (actually, im a newb regarding turbo setups), but I would really like to have a option for Twin Turbos over the single.
Quick spool with good torque/hp from the bottom rpm is what I want.
Was thinking that with the GT35, hey would be small enough and with its quick spool, would give good low-mid power and peak power ofc.
I'm not a expert in any way on turbo specs and etcs (actually, im a newb regarding turbo setups), but I would really like to have a option for Twin Turbos over the single.
Quick spool with good torque/hp from the bottom rpm is what I want.
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Will be waiting to see how this goes.
Just waiting on my engine to come back to me from rx7store.
After I get my car running again, get AI and a few other supporting mods, i'll be looking at the turbo options... this is one.
Just waiting on my engine to come back to me from rx7store.
After I get my car running again, get AI and a few other supporting mods, i'll be looking at the turbo options... this is one.
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