Non-turbo 428rwhp FD build up and history
Here are some updates that have been done over the months--
Removed the windshield and fabricated some a-pillar plates

Had some rotor hats cnc machined to adapt the nextel cup/alms braking system to the Rx-7. These are monoblock, radial mount, titanium insert staggered piston calipers. And Performance Fiction dimpled rotors with full floating mounting.


Remade the rear exhaust system, to shed weight and possibly free up some more horsepower. This system was 60lbs lighter once complete!


Went to some new wheels, enkei Rp-f1 18x10.5 on all four corners. Then wrapped in hoosier R6's. 285 up front and 315 in the rear. These dropped over 34lbs off the car total.

Fabricated the fuel cell and drysump enclosures to meet the SCCA and NASA rules, and finally mounted the ATL drybreak system. Also made the drysump tank vent tubes with built in catch can.



Removed the windshield and fabricated some a-pillar plates

Had some rotor hats cnc machined to adapt the nextel cup/alms braking system to the Rx-7. These are monoblock, radial mount, titanium insert staggered piston calipers. And Performance Fiction dimpled rotors with full floating mounting.


Remade the rear exhaust system, to shed weight and possibly free up some more horsepower. This system was 60lbs lighter once complete!


Went to some new wheels, enkei Rp-f1 18x10.5 on all four corners. Then wrapped in hoosier R6's. 285 up front and 315 in the rear. These dropped over 34lbs off the car total.

Fabricated the fuel cell and drysump enclosures to meet the SCCA and NASA rules, and finally mounted the ATL drybreak system. Also made the drysump tank vent tubes with built in catch can.



You shaved 60lbs from the exhaust system?? what in the name of buddha did you make out of in the first place, iron ore?? LOL.
all joking aside, have you made the new exhaust from titanium?
all joking aside, have you made the new exhaust from titanium?
Thank you! The answer to that is yes and no. It is producing higher numbers than the majority of full race 20b p-port engines. I know of at least one race 20b full p-port that is making about 30hp over mine. Its a $55k mazda backed lemans project though. But I am not finished getting more power yet 

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20B Three rotor rotary engine (1,950cc)
Max Power 425HP @ 8500RPM
Max Torque 285 ft-lbs. @ 7600
Max RPM 8800
Dry Sump Lubrication
Bosch 4.3 ECU
(http://www.speedsourceinc.com/index...._profile_id=59)
Everytime I take a peak into this thread.. It makes me want to make a new post in the "FD for sale section"... and start over again.. LOL
Also we met at gordons Dyno Day a month or so back.... I was the Black FD from NY, we hung out at that pizza spot after. Anyway Here are some Pics I took of the headers you did for gordon. Feel free to use them on your site.


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20B Three rotor rotary engine (1,950cc)
Max Power 425HP @ 8500RPM
Max Torque 285 ft-lbs. @ 7600
Max RPM 8800
Dry Sump Lubrication
Bosch 4.3 ECU
(http://www.speedsourceinc.com/index...._profile_id=59)
Everytime I take a peak into this thread.. It makes me want to make a new post in the "FD for sale section"... and start over again.. LOL
Also we met at gordons Dyno Day a month or so back.... I was the Black FD from NY, we hung out at that pizza spot after. Anyway Here are some Pics I took of the headers you did for gordon. Feel free to use them on your site.


Logan... how much power are the Speedsource cars making? Have you spoken with or had a chance to compare notes with their engine builder? He's a young guy.... can't remember his name. Anyway, if you attend Sevenstock there's a good chance you could meet up with him to chat and compare technical info (if you haven't already). Looking forward to seeing you, Gordon, and hopefully Rich this Fall in Irvine!
Close
^
20B Three rotor rotary engine (1,950cc)
Max Power 425HP @ 8500RPM
Max Torque 285 ft-lbs. @ 7600
Max RPM 8800
Dry Sump Lubrication
Bosch 4.3 ECU
(http://www.speedsourceinc.com/index...._profile_id=59)
Everytime I take a peak into this thread.. It makes me want to make a new post in the "FD for sale section"... and start over again.. LOL
Also we met at gordons Dyno Day a month or so back.... I was the Black FD from NY, we hung out at that pizza spot after. Anyway Here are some Pics I took of the headers you did for gordon. Feel free to use them on your site.
^
20B Three rotor rotary engine (1,950cc)
Max Power 425HP @ 8500RPM
Max Torque 285 ft-lbs. @ 7600
Max RPM 8800
Dry Sump Lubrication
Bosch 4.3 ECU
(http://www.speedsourceinc.com/index...._profile_id=59)
Everytime I take a peak into this thread.. It makes me want to make a new post in the "FD for sale section"... and start over again.. LOL
Also we met at gordons Dyno Day a month or so back.... I was the Black FD from NY, we hung out at that pizza spot after. Anyway Here are some Pics I took of the headers you did for gordon. Feel free to use them on your site.
Yep those are the speedsource specs at the flywheel. Too bad they have such hard restrictions to deal with now. Thanks for offering us to use the photos, they look great! We definitely will put them on the site. Haha thanks! It scares me a little on the racetrack too, lol. Trying to order that driving skills package so I can keep up with it!
So friday I finally did get a chance to visit the dyno. Had a strange feeling it wasnt going to go well for some reason. Keep in mind the only thing that changed is the header back exhaust system. First pull was 390rwhp...... ouch. New exhaust lost some power and was richer than before. After a re-tune it was up to 405rwhp, which is still 30hp down. Figured I would post this to show that its not all fun and games going for more power n/a. They are very sensitive engines and all the details count. No big deal, the new exhaust needs some tweaking and the power will be back soon. So here is the chart to show the stellar losses 

Bit off a bummer that. I'm sure you will squeeze those numbers back. Have you ever tried running the exhaust off on the dyno? Just the headerssticking out of the behind the front wheel?
Or is just full pp engines that benefit from that? As when I emailed racing beat, with some questions about running a 13B pp in my rx4 (sadly now I'm going full bridge BW turbo) jim mederer said to run a short exhaust as possible with a pp straight out behind the front wheel.
This couldn't be an option as it has to driven on the road.
Or is just full pp engines that benefit from that? As when I emailed racing beat, with some questions about running a 13B pp in my rx4 (sadly now I'm going full bridge BW turbo) jim mederer said to run a short exhaust as possible with a pp straight out behind the front wheel.
This couldn't be an option as it has to driven on the road.
I think that the short exhaust would mainly benefit a full pp, due to reducing the back pressure and in turn reducing the overlap that a pp engine has.
Tuned length exhausts may be better for the setup we are looking at here as we have a blend of different ports and scalloped rotors? I think?
Tuned length exhausts may be better for the setup we are looking at here as we have a blend of different ports and scalloped rotors? I think?
Bit off a bummer that. I'm sure you will squeeze those numbers back. Have you ever tried running the exhaust off on the dyno? Just the headerssticking out of the behind the front wheel?
Or is just full pp engines that benefit from that? As when I emailed racing beat, with some questions about running a 13B pp in my rx4 (sadly now I'm going full bridge BW turbo) jim mederer said to run a short exhaust as possible with a pp straight out behind the front wheel.
This couldn't be an option as it has to driven on the road.
Or is just full pp engines that benefit from that? As when I emailed racing beat, with some questions about running a 13B pp in my rx4 (sadly now I'm going full bridge BW turbo) jim mederer said to run a short exhaust as possible with a pp straight out behind the front wheel.
This couldn't be an option as it has to driven on the road.
Seeing as impractical open headers really are even in a track setting, I probably wont do much testing in that area for a while. Optimized correctly, it could make a bit more power though.
On a side note, it seems that if the setup is not optimal and not seeing ram effect, then a change will only effect one area of the powerband. This effect is still much less than optimized exhaust system.
I think that the short exhaust would mainly benefit a full pp, due to reducing the back pressure and in turn reducing the overlap that a pp engine has.
Tuned length exhausts may be better for the setup we are looking at here as we have a blend of different ports and scalloped rotors? I think?
Tuned length exhausts may be better for the setup we are looking at here as we have a blend of different ports and scalloped rotors? I think?
Just looked at your dyno read out. It is probably the first time I have looked at one and understood what I'm looking at if I'm honest.
Am I right in saying that you HP peaks around 9,600 rpm and appears to level out flat? Do you think your engine could produce power above and beyond 10,000 rpm?
Or would you say that to make more power beyond 10,000 rpm to say 12,000 rpm a full pp would be better to achieve that?
Are you in the process of building individual throttle bodies for each individual port? Or did I read that somewhere else?!
Would individual TBs yield better throttle response?
Am I right in saying that you HP peaks around 9,600 rpm and appears to level out flat? Do you think your engine could produce power above and beyond 10,000 rpm?
Or would you say that to make more power beyond 10,000 rpm to say 12,000 rpm a full pp would be better to achieve that?
Are you in the process of building individual throttle bodies for each individual port? Or did I read that somewhere else?!
Would individual TBs yield better throttle response?
Just looked at your dyno read out. It is probably the first time I have looked at one and understood what I'm looking at if I'm honest.
Am I right in saying that you HP peaks around 9,600 rpm and appears to level out flat? Do you think your engine could produce power above and beyond 10,000 rpm?
Or would you say that to make more power beyond 10,000 rpm to say 12,000 rpm a full pp would be better to achieve that?
Are you in the process of building individual throttle bodies for each individual port? Or did I read that somewhere else?!
Would individual TBs yield better throttle response?
Am I right in saying that you HP peaks around 9,600 rpm and appears to level out flat? Do you think your engine could produce power above and beyond 10,000 rpm?
Or would you say that to make more power beyond 10,000 rpm to say 12,000 rpm a full pp would be better to achieve that?
Are you in the process of building individual throttle bodies for each individual port? Or did I read that somewhere else?!
Would individual TBs yield better throttle response?
Yes the ITB system is almost done, and then testing will start.Yep, should have even faster throttle response which is already extremely fast. Here is a teaser pic of the semi p-port slide throttles
When you say slide tb, do you mean a flat slide? Like on a carb'd air-cooled 2stroke?
As opposed to a butterfly style tb.
What arethe advantages to a slide tb? Increased flow due to the restrictor (only word I can think to describe it) being moved out of the airflows path versus a butterfly which still is in the way?
As opposed to a butterfly style tb.
What arethe advantages to a slide tb? Increased flow due to the restrictor (only word I can think to describe it) being moved out of the airflows path versus a butterfly which still is in the way?
Joined: May 2005
Posts: 2,745
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From: North Bay, Ontario
When you say slide tb, do you mean a flat slide? Like on a carb'd air-cooled 2stroke?
As opposed to a butterfly style tb.
What arethe advantages to a slide tb? Increased flow due to the restrictor (only word I can think to describe it) being moved out of the airflows path versus a butterfly which still is in the way?
As opposed to a butterfly style tb.
What arethe advantages to a slide tb? Increased flow due to the restrictor (only word I can think to describe it) being moved out of the airflows path versus a butterfly which still is in the way?
But, I think the biggest advantage is being able to position the throttlebody as close to the port face as possible, reducing the distance between the closed throttlebody and the intake chamber, which should let it idle and run smoother in low-loads due to less intake contamination. You wouldn't be able to get other types of TB's to seal that close to the block. Plus I'm sure he'll be keeping those runners nice and short too to boost power in the upper RPM
Logan, how do you seal the flat slides anyways?









