my semi-peripheral project
#76
Scott Howard
![](https://www.rx7club.com/images/misc/15_year_icon.png)
if you wanted to stay in the current class, since you've already met the max HP, the trick would be to make the powerband as flat and broad as possible.
next class up, might be full PP or 3 rotor or something
these are good problems! if we put the honda in PT, we're overweight and underpowered...
next class up, might be full PP or 3 rotor or something
these are good problems! if we put the honda in PT, we're overweight and underpowered...
I'm going to focus on stiffining the chassis and aero for now. I want to fab a rear diffuser, and continue a partial undertray that will end just aft of the firewall.
There is still a chance I might do something to the porting this winter so I will be competitive in ST1.
#77
Moderator
![](/images/misc/20_year_icon.png)
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,982
Received 2,688 Likes
on
1,903 Posts
#78
Old [Sch|F]ool
![](/images/misc/20_year_icon.png)
I did my peripheral port with no sleeves... well, they are half-sleeves, there's something for the intake manifold to clamp to, but they only extend halfway into the water jacket. I did it this way because I wanted port timing that was "shorter" than the diameter of the port.
Lessons learned:
1. It took way too much more time. Like doing a street port times doing a bridge port. Reefing a hole through and fitting a sleeve would take about 1/3rd the time.
2. You can't fit very much port in a 12A so start with a 13B. Sucks but true.
3. If you don't extend the sleeves all the way through, the housing may crush from the lack of support at the intake area. I left 1/2" of aluminum on the sides, when I disassembled the engine the rotor housings were about .003 narrower in that spot and cracks were noted.
Oh and the point behind the excercise -
4. A full peripheral port is just as drivable and quiet as a large street port given the same exhaust system. Some things you just have to do for yourself...
#79
Oh and the point behind the excercise -
4. A full peripheral port is just as drivable and quiet as a large street port given the same exhaust system. Some things you just have to do for yourself...
4. A full peripheral port is just as drivable and quiet as a large street port given the same exhaust system. Some things you just have to do for yourself...
#80
Old [Sch|F]ool
![](/images/misc/20_year_icon.png)
Yeah, last spring I made an EFI intake manifold for it, fixed some of the epoxy failures, reassembled it, and threw it in the car. I always did want to try it out with EFI, but mainly it was the last engine I had available to me and the GSL-SE engine I had in there died a mysterious death.
http://viewmorepics.myspace.com/inde...albumId=784515
What happened was it had ignition issues that I could not resolve (plugs would get funky in the space of a few blocks) that made it have horrible transition no matter what I did, and it didn't make much power because my TB was too small (~85KPa at full throttle!) and HP estimates from injector pulsewidths had it at roughly 120-130hp. With a better intake setup and a more free flowing exhaust it probably would have woken right up.
I drove it around for a few thousand miles while I acquired the bits for my 13BT engine, then swapped it out. It's currently holding down part of a friend's garage floor:
http://viewmorepics.myspace.com/inde...albumId=784515
What happened was it had ignition issues that I could not resolve (plugs would get funky in the space of a few blocks) that made it have horrible transition no matter what I did, and it didn't make much power because my TB was too small (~85KPa at full throttle!) and HP estimates from injector pulsewidths had it at roughly 120-130hp. With a better intake setup and a more free flowing exhaust it probably would have woken right up.
I drove it around for a few thousand miles while I acquired the bits for my 13BT engine, then swapped it out. It's currently holding down part of a friend's garage floor:
#81
Senior Member
![](https://www.rx7club.com/images/misc/15_year_icon.png)
iTrader: (17)
Join Date: Jan 2005
Location: Jackson, Mo
Posts: 441
Likes: 0
Received 0 Likes
on
0 Posts
Hey your ports look good, that pic with the light coming through the ports looks sic! Sorry to hear about all the set-backs. Sorry i haven't posted in a while i got busy with school and work and insufficient funds. I'm so close to getting mine running. I've got it to run really crapy on just the street ports, but I'm having troubles riggin up, or I mean fabricating
up some runners for the p-ports, it sucks not having any decent tools!
![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
#83
Can Post Only in New Member Section
Join Date: Nov 2018
Location: georgetown
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
some more pics
this is my epoxy work that i finished 2 days ago. i need to machine a meniscus into it, but haven't done so yet.
Attachment 721366
Attachment 721367
this is my epoxy work that i finished 2 days ago. i need to machine a meniscus into it, but haven't done so yet.
Attachment 721366
Attachment 721367
#84
welcome to the board. ![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
sorry i didn't see this sooner. i know it's been six months, but i will respond anyway.
the epoxy's job may be twofold.
1. depending on what engine you're starting with, it blocks the water passages. they might otherwise leak.
2. i think they help to keep the sleeves in place. if they were professionally done, i would imagine this would be less of an issue, but since i did them myself, i thought of the epoxy as an extra benefit for this.
![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
sorry i didn't see this sooner. i know it's been six months, but i will respond anyway.
the epoxy's job may be twofold.
1. depending on what engine you're starting with, it blocks the water passages. they might otherwise leak.
2. i think they help to keep the sleeves in place. if they were professionally done, i would imagine this would be less of an issue, but since i did them myself, i thought of the epoxy as an extra benefit for this.
#85
11 years later ...
so, for anyone interested, this project never got to the point of a functional engine.
the side housings went to my FC and are simply a streetport engine right now. the semi-pp rotor housings are still just sitting here. in my estimation, they will probably not get used because at some point i tried to get the timing on both housings perfectly matched, and ended up making a mistake that i think it would take a machinist to fix. so they may just be paperweights now. i guess we will see.
at any rate, at some point (maybe around 2014 or so) i had a fellow club member do some housings for another engine for me, and he's a professional, so when i build that engine, i will have my first semi-pp. it's all on the back-burner now, but it's something that i plan to see all the way through. will likely not make a new thread when the time comes. i will just find this one and update it.
so, for anyone interested, this project never got to the point of a functional engine.
the side housings went to my FC and are simply a streetport engine right now. the semi-pp rotor housings are still just sitting here. in my estimation, they will probably not get used because at some point i tried to get the timing on both housings perfectly matched, and ended up making a mistake that i think it would take a machinist to fix. so they may just be paperweights now. i guess we will see.
at any rate, at some point (maybe around 2014 or so) i had a fellow club member do some housings for another engine for me, and he's a professional, so when i build that engine, i will have my first semi-pp. it's all on the back-burner now, but it's something that i plan to see all the way through. will likely not make a new thread when the time comes. i will just find this one and update it.