Custom Twin T3/TO4E Set Up
01-28-09, 06:23 PM
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Custom Twin T3/TO4E Set Up
Hey Guys, just wanted to start a post about my custom twin turbo set up and see what you think. I'm waiting for the new water pump so and block off plate so I ca have even more room to fabricate the exhaust manifold. I also ripped out the gas tank and will replace it with a 17+ gallon Fuel Safe fuel cell soon(making room for dual HKS carbon TI exhausts). Here is a pic of the turbos so far, let me know what you guys think, I'll have more pictures in a few weeks.
Last edited by spiritrmazda; 01-28-09 at 06:38 PM. Reason: Images didn't come out right and didn't make the right title.
01-28-09, 10:36 PM
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They're not as big as Howard's, I've read his posts so many times, I'm beginning to think I'm modeling mine after his with a few differences. .63 A/R, 40 trim compressors, HKS GT wastegate with 2x 2.5 or 3" piping all the way to back with HKS carbon TI mufflers on each side(think I'm the first with these so far) and a custom twin core v-mcount intercooler.
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01-29-09, 06:55 AM
#16
Racing Rotary Since 1983
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here's a little secret... internal wastegates rip.
back in the old days before ATP came out w their "Ultimate Wastegate" it was different... you had to run the dreadful Garrett "Ford" 5 bolt casting w the 2.1 inch exhaust orfice. now it is free flow 3 inch V band. i have been running ATP backends for 4 years and had the first.
i doubt i would have built my twins if i had had to run either the crummy stock internal wastegate casting or screw w all the external piping.
as to your turbos... 37 lbs per minute at 23 psi is max from each... so 74 lbs/min is 1070 CFM/1.92 equals 557 max rotary rear wheel hp.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
good luck,
howard
back in the old days before ATP came out w their "Ultimate Wastegate" it was different... you had to run the dreadful Garrett "Ford" 5 bolt casting w the 2.1 inch exhaust orfice. now it is free flow 3 inch V band. i have been running ATP backends for 4 years and had the first.
i doubt i would have built my twins if i had had to run either the crummy stock internal wastegate casting or screw w all the external piping.
as to your turbos... 37 lbs per minute at 23 psi is max from each... so 74 lbs/min is 1070 CFM/1.92 equals 557 max rotary rear wheel hp.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
good luck,
howard
01-29-09, 07:57 AM
#17
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here's a little secret... internal wastegates rip.
back in the old days before ATP came out w their "Ultimate Wastegate" it was different... you had to run the dreadful Garrett "Ford" 5 bolt casting w the 2.1 inch exhaust orfice. now it is free flow 3 inch V band. i have been running ATP backends for 4 years and had the first.
i doubt i would have built my twins if i had had to run either the crummy stock internal wastegate casting or screw w all the external piping.
as to your turbos... 37 lbs per minute at 23 psi is max from each... so 74 lbs/min is 1070 CFM/1.92 equals 557 max rotary rear wheel hp.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
good luck,
howard
back in the old days before ATP came out w their "Ultimate Wastegate" it was different... you had to run the dreadful Garrett "Ford" 5 bolt casting w the 2.1 inch exhaust orfice. now it is free flow 3 inch V band. i have been running ATP backends for 4 years and had the first.
i doubt i would have built my twins if i had had to run either the crummy stock internal wastegate casting or screw w all the external piping.
as to your turbos... 37 lbs per minute at 23 psi is max from each... so 74 lbs/min is 1070 CFM/1.92 equals 557 max rotary rear wheel hp.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
good luck,
howard
01-29-09, 12:12 PM
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Great stuff. To do the true dual exhaust I think you will need to modify or move the gas tank. I have considered this for a long time and there's no room on the driver's side for a pipe much less muffler. You could run the pipes to the back of the diff and have a tranverse muffler behind the diff. Narrow the gas tank and make it deeper.
Gordon
Gordon
01-29-09, 09:10 PM
#21
Howard,
this is the wastegate you are running?
http://www.atpturbo.com/Merchant2/me...egory_Code=BCS
and that bolts up to any 5 bolt Ford-style discharge... but it is better than an OEM-grade Ford wastegate. Correct? I have looked through ATP's wastegate offerings.
You are saying that the one you are using is superior to this one:
http://www.atpturbo.com/Merchant2/me...egory_Code=BCS
Why is that, if they were both being attached to the same hypothetical standard 5 bolt turbine housing for testing purposes? I can see the "Ultimate" one has a much more gradual radius to it. Is the flapper bigger or something? Are you porting the wastegate passageway on the turbine housings at all?
this is the wastegate you are running?
http://www.atpturbo.com/Merchant2/me...egory_Code=BCS
and that bolts up to any 5 bolt Ford-style discharge... but it is better than an OEM-grade Ford wastegate. Correct? I have looked through ATP's wastegate offerings.
You are saying that the one you are using is superior to this one:
http://www.atpturbo.com/Merchant2/me...egory_Code=BCS
Why is that, if they were both being attached to the same hypothetical standard 5 bolt turbine housing for testing purposes? I can see the "Ultimate" one has a much more gradual radius to it. Is the flapper bigger or something? Are you porting the wastegate passageway on the turbine housings at all?
01-30-09, 06:25 AM
#22
Racing Rotary Since 1983
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it is all about flow. the ATP has a really nice taper around the two orfices and the stock one has a flat surface that the wastegated flow runs into head-on. further, the stocker exhaust measures 2.1 inches and the ATP measures 3 inches. it is one slick piece.
hc
hc
01-30-09, 12:12 PM
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as to your turbos... 37 lbs per minute at 23 psi is max from each... so 74 lbs/min is 1070 CFM/1.92 equals 557 max rotary rear wheel hp.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
i have been thru 5 iterations on my turbo sizing. they are now perfect for my needs.
TO4 46 trim 44 lbs per minute... about 630 rear wheel at 26-27 psi.
the hot side is extremely important on a rotary. you need to go big. i run .82 A/R with stage 5 wheels.
.63 will be o k but not optimum. what size turbine wheel do you have? they need to be either a stage 3 or 5.
BTW, EGTs become key as you reach redline and they are partially a factor of EBP (exhaust back pressure). my EBP is 23 preturbo at 21 psi boost! that's why my EGTs are nice at 1550 preturbo at 8200. i run about 25% methanol under boost.
Stressing the importance of a high turbine A/R, a lot of hotside as you put it, I'm guessing this is to maximize the horsepower output at top end? I imagine you spend a lot of time in high revs while road racing. However, being dual purpose, how is your turbo response on the street? How do turbine housings affect response time vis-a-vis max output?
Would you consider dedicating a thread to your turbo research in the future?
01-30-09, 03:51 PM
#25
Racing Rotary Since 1983
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"Stressing the importance of a high turbine A/R, a lot of hotside as you put it, I'm guessing this is to maximize the horsepower output at top end?"
"being dual purpose, how is your turbo response on the street? How do turbine housings affect response time vis-a-vis max output?"
the primary purpose of the larger hotsides is to lower exhaust gas temperature.
the turbine wheels are lightened but still large and heavy. the housing size works fine on the street.
my fd makes 200 rwhp around 4200 rpm. a typical GT42 that puts out the same 84 lbs per minute makes 200 around 4750. check thru dyno sheets and you will see that my midrange is similar to a well tuned GT35r but my top end is similar to a GT42.
this year i am building a new motor that will have an exhaust port that will add lots of midrange. you can greatly effect spool w the exhaust port configuration. i am also adding an intake port that gives me 20 degrees more duration so i should have more top end.
(of course i want more of everything)
the large hotside is to both exploit the heat coming from the rotary to drive the turbos at all boost levels as well as to rid the engine of excess heat expressed as EGTs. my engine, due to it's larger hotsides, runs 150+ degrees cooler than your typical single turbo setup.
as an aside, there have been 6 twin setups built in the last 6 years and all but mine, i believe, are in the scrap pile. each was built differently... i have about 17,000 miles on my twins and love them.
hc
"being dual purpose, how is your turbo response on the street? How do turbine housings affect response time vis-a-vis max output?"
the primary purpose of the larger hotsides is to lower exhaust gas temperature.
the turbine wheels are lightened but still large and heavy. the housing size works fine on the street.
my fd makes 200 rwhp around 4200 rpm. a typical GT42 that puts out the same 84 lbs per minute makes 200 around 4750. check thru dyno sheets and you will see that my midrange is similar to a well tuned GT35r but my top end is similar to a GT42.
this year i am building a new motor that will have an exhaust port that will add lots of midrange. you can greatly effect spool w the exhaust port configuration. i am also adding an intake port that gives me 20 degrees more duration so i should have more top end.
(of course i want more of everything
)the large hotside is to both exploit the heat coming from the rotary to drive the turbos at all boost levels as well as to rid the engine of excess heat expressed as EGTs. my engine, due to it's larger hotsides, runs 150+ degrees cooler than your typical single turbo setup.
as an aside, there have been 6 twin setups built in the last 6 years and all but mine, i believe, are in the scrap pile. each was built differently... i have about 17,000 miles on my twins and love them.
hc