At a crossroads (bridge vs. street content)
02-10-10, 11:21 PM
#1
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At a crossroads (bridge vs. street content)
I yanked my engine today (yesterday) for the winter inspection/freshening.
To recap, it's 13BT housings with a healthy street port, S4 N/A rotating assembly, and a few minor life-extension things like FD corner seal springs, rotor clearancing, and higher oil pressure. Nothing exotic at all. It's seen 5 figures a couple times although that was strictly by accident.
The Atkins seals aren't terribly kind to the rotor housings, but they're still servicable. No flaking but there is some circumferential grooving, nowhere near as bad as the RA seals have been known to do. Chatter marks next to nonexistent. Side seals looking good. Coolant seal lands still holding the coolant seals.
I would LIKE more mid-range torque. The ports are already fairly huge, especially the primary ports. I don't think the primary ports can be made to open any earlier, while it looks like the opening line of the secondaries hasn't been touched at all.
I have two courses of action I've been thinking of taking:
One, open up the opening lines to within 11mm of the coolant seal, bevel the rotors to increase that even more.
I don't think there will be gained here, and beveling the rotors without rebalancing is giving me the heebie-jeebies. This engine sees stupid RPM on a fairly regular basis, I'd like it to hold together. Which leads me to...
Two, mild half-bridge. No relief, 5mm wide bridge.
I DO drive this thing on the street. I also used to drive a peripheral port on the street so I kinda know what I am getting in to
With EFI it was almost pleasant to drive even on the highway. The P-port had lots of spark plug fouling issues though which is the only thing making me not want to do half-bridge.
That, and my apex seals are two-piece, although they are Atkins two-piece so the corner piece is huge, and I don't plan on doing a rotor housing relief anyway. Given that the seals are already broken in on the housings and the housings are starting to show some grooving, I don't want to flip the rears around.
I estimate my current power at about 210-215 at the crank. I don't really want more power, I want to shift the existing power lower.
To recap, it's 13BT housings with a healthy street port, S4 N/A rotating assembly, and a few minor life-extension things like FD corner seal springs, rotor clearancing, and higher oil pressure. Nothing exotic at all. It's seen 5 figures a couple times although that was strictly by accident.
The Atkins seals aren't terribly kind to the rotor housings, but they're still servicable. No flaking but there is some circumferential grooving, nowhere near as bad as the RA seals have been known to do. Chatter marks next to nonexistent. Side seals looking good. Coolant seal lands still holding the coolant seals.
I would LIKE more mid-range torque. The ports are already fairly huge, especially the primary ports. I don't think the primary ports can be made to open any earlier, while it looks like the opening line of the secondaries hasn't been touched at all.
I have two courses of action I've been thinking of taking:
One, open up the opening lines to within 11mm of the coolant seal, bevel the rotors to increase that even more.
I don't think there will be gained here, and beveling the rotors without rebalancing is giving me the heebie-jeebies. This engine sees stupid RPM on a fairly regular basis, I'd like it to hold together. Which leads me to...
Two, mild half-bridge. No relief, 5mm wide bridge.
I DO drive this thing on the street. I also used to drive a peripheral port on the street so I kinda know what I am getting in to
With EFI it was almost pleasant to drive even on the highway. The P-port had lots of spark plug fouling issues though which is the only thing making me not want to do half-bridge.That, and my apex seals are two-piece, although they are Atkins two-piece so the corner piece is huge, and I don't plan on doing a rotor housing relief anyway. Given that the seals are already broken in on the housings and the housings are starting to show some grooving, I don't want to flip the rears around.
I estimate my current power at about 210-215 at the crank. I don't really want more power, I want to shift the existing power lower.
02-11-10, 12:58 PM
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aww... i was about to tell you again about my friends BP. he did a full bridge, BUT he made it wide so it opened and closed shorter than a normal monster bridge, think high lift short duration cam.
with a dialed in holley, it got 20+ mpg on the freeway, and was dead reliable on the street. i'd say streetable but it did have the brap brap idle, so it was kind of intense for a daily.
QUIET uncollected exhaust, tq curve was FLAT, it made 231rwhp@when the dyno stopped reading at 9600rpms...
with a dialed in holley, it got 20+ mpg on the freeway, and was dead reliable on the street. i'd say streetable but it did have the brap brap idle, so it was kind of intense for a daily.
QUIET uncollected exhaust, tq curve was FLAT, it made 231rwhp@when the dyno stopped reading at 9600rpms...
02-11-10, 01:44 PM
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lol, i know.... so sad...
oh yeah, if the housings are getting beat might wanna add more metering oil
oh yeah, if the housings are getting beat might wanna add more metering oil
02-12-10, 10:23 PM
#7
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http://www.youtube.com/watch?v=6X9zvZr2fLc
This should make the direction I went... obvious
This thing really wants a lot less fuel at idle. I poured gasoline out of the exhaust hose after only about 30 seconds of run time.
This should make the direction I went... obvious
This thing really wants a lot less fuel at idle. I poured gasoline out of the exhaust hose after only about 30 seconds of run time.
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02-13-10, 01:48 PM
#9
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I pulled the car into the shop on Wednesday around 1:30, engine was out at 3, disassembled and external parts cleaned by 5:30, hemmed and hawed about the porting on Thursday until I finally said "screw it, if I don't like the BP then I'll do another street port but rotor beveling can't be undone" and the housings were done porting by something like 2pm, engine block was assembled from 4 to 5:30, Friday had me putting the rest of it together (including tapping the rotor housings for 1/2" pipe plugs to eliminate coolant leaks, since I COULD NOT FIND 3/4 freeze plugs ANYWHERE, and cleaning up a FC water pump housing/removing broken T0stat bolts), started putting it in after lunch, and, well, that video was taken around 5:20 Friday afternoon.
I had a busy half-week
Part of why I did it that fast is because I'm always pressed for time to work on the car and every minute is precious to me. The other part is, I used to always say that a person could do a "weekend port job" where they pull the engine out on Friday after work and have it out, ported, and back together by Monday morning. I didn't do a complete port job but I did also only have 8 hour days in which to work.
I can't wait for my laptop backlight to come in (ordered an XGA, they shipped a WXGA... grr!) so I can tune the thing.
Sure beats the hell out of building a peripheral port, that is for sure. That took a seriously long time, given all of the different things that had to be accomplished.
I had a busy half-week
Part of why I did it that fast is because I'm always pressed for time to work on the car and every minute is precious to me. The other part is, I used to always say that a person could do a "weekend port job" where they pull the engine out on Friday after work and have it out, ported, and back together by Monday morning. I didn't do a complete port job but I did also only have 8 hour days in which to work.
I can't wait for my laptop backlight to come in (ordered an XGA, they shipped a WXGA... grr!) so I can tune the thing.
Sure beats the hell out of building a peripheral port, that is for sure. That took a seriously long time, given all of the different things that had to be accomplished.
02-13-10, 02:54 PM
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I pulled the car into the shop on Wednesday around 1:30, engine was out at 3, disassembled and external parts cleaned by 5:30, hemmed and hawed about the porting on Thursday until I finally said "screw it, if I don't like the BP then I'll do another street port but rotor beveling can't be undone" and the housings were done porting by something like 2pm, engine block was assembled from 4 to 5:30, Friday had me putting the rest of it together (including tapping the rotor housings for 1/2" pipe plugs to eliminate coolant leaks, since I COULD NOT FIND 3/4 freeze plugs ANYWHERE, and cleaning up a FC water pump housing/removing broken T0stat bolts), started putting it in after lunch, and, well, that video was taken around 5:20 Friday afternoon.
I had a busy half-week
Part of why I did it that fast is because I'm always pressed for time to work on the car and every minute is precious to me. The other part is, I used to always say that a person could do a "weekend port job" where they pull the engine out on Friday after work and have it out, ported, and back together by Monday morning. I didn't do a complete port job but I did also only have 8 hour days in which to work.
I can't wait for my laptop backlight to come in (ordered an XGA, they shipped a WXGA... grr!) so I can tune the thing.
Sure beats the hell out of building a peripheral port, that is for sure. That took a seriously long time, given all of the different things that had to be accomplished.
I had a busy half-week
Part of why I did it that fast is because I'm always pressed for time to work on the car and every minute is precious to me. The other part is, I used to always say that a person could do a "weekend port job" where they pull the engine out on Friday after work and have it out, ported, and back together by Monday morning. I didn't do a complete port job but I did also only have 8 hour days in which to work.
I can't wait for my laptop backlight to come in (ordered an XGA, they shipped a WXGA... grr!) so I can tune the thing.
Sure beats the hell out of building a peripheral port, that is for sure. That took a seriously long time, given all of the different things that had to be accomplished.
my best time is actually on a 99 miata, 14 hours. my friend did a 1st gen in about 10, and i think he best his time with an FD in like 8...
no porting though....
02-15-10, 01:44 PM
#12
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Thread Starter
So, I drove it today, untuned.
Oh holy geez. I might need 245s in the back.
---
Okay, so I forgot to check timing. It was at 12 degrees.
Yeah, gonna need bigger tires. Blows away the 225/50s.
Oh holy geez. I might need 245s in the back.
---
Okay, so I forgot to check timing. It was at 12 degrees.
Yeah, gonna need bigger tires. Blows away the 225/50s.
02-15-10, 06:13 PM
#14
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Thread Starter
Well, it started snowing as I was putting the oil pressure/temp gauges in, so the car is going to be immobile for a while again. It doesn't move if there is the least amount of snow on the ground.
The tire problem is something that I'm going to have to mull over for a while. The main problem is, I am having a very hard time finding wide wheels in a 4x4.5 bolt pattern, in any diameter. (I am switching to FC front suspension/GSL-SE rear axles this winter)
In 4x110, I have my 15x7 Koseis and my 15x6 something-or-others (BBS? something). Currently have gForce Sports on the Koseis and I am hoping most of my traction problems are due to the 30-odd degree temperatures. But even so, this thing pulls HARD even untuned.
For the new bolt pattern, I have a bunch of phone dials and a set of 240SX 15x6 wheels that the rally tires will be going on. For the phone dials, I can get 235/60 no problem, and I know 245/60 will fit as well since I've had a lot of customer cars with that setup, and my first car had 245/60-15 on 6" rims. They can't be had in a decent tread compound, though.
I did grab some 17x7 wheels from some guy who had them on his Accord, but the most tire I can fit on there and keep a decent tire diameter is 215/40. I am unsure if this will even be enough.
What I may end up doing is keeping the 110 on the back and running something gummy and wide on two Koseis. I'm keeping my eyes peeled for some 8" or wider wheels, though.
The tire problem is something that I'm going to have to mull over for a while. The main problem is, I am having a very hard time finding wide wheels in a 4x4.5 bolt pattern, in any diameter. (I am switching to FC front suspension/GSL-SE rear axles this winter)
In 4x110, I have my 15x7 Koseis and my 15x6 something-or-others (BBS? something). Currently have gForce Sports on the Koseis and I am hoping most of my traction problems are due to the 30-odd degree temperatures. But even so, this thing pulls HARD even untuned.
For the new bolt pattern, I have a bunch of phone dials and a set of 240SX 15x6 wheels that the rally tires will be going on. For the phone dials, I can get 235/60 no problem, and I know 245/60 will fit as well since I've had a lot of customer cars with that setup, and my first car had 245/60-15 on 6" rims. They can't be had in a decent tread compound, though.
I did grab some 17x7 wheels from some guy who had them on his Accord, but the most tire I can fit on there and keep a decent tire diameter is 215/40. I am unsure if this will even be enough.
What I may end up doing is keeping the 110 on the back and running something gummy and wide on two Koseis. I'm keeping my eyes peeled for some 8" or wider wheels, though.
02-16-10, 08:24 PM
#16
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Thread Starter
I did some checking around and you CAN get relatively cheap steel wheels in 15x8 or even wider.
The next problem becomes, I remember you used to be able to get 245, 255, 265, and even 275/50 tires in 15". Not anymore. AUGH
I'm just going to go back to my original plan of gummy 215/40 Falkens on these 17" wheels. Not drag-launch tires but I don't really drag race, so that's okay.
The next problem becomes, I remember you used to be able to get 245, 255, 265, and even 275/50 tires in 15". Not anymore. AUGH
I'm just going to go back to my original plan of gummy 215/40 Falkens on these 17" wheels. Not drag-launch tires but I don't really drag race, so that's okay.
02-18-10, 07:01 PM
#17
I know, you mention it about every other time we talk
http://www.ohiorotaries.com/smf/inde...31816#msg31816
http://www.ohiorotaries.com/smf/inde...31816#msg31816
B2600R 4wd trans?
02-18-10, 07:32 PM
#18
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Thread Starter
No...
If Paul shows up at the rallycross this weekend with his wagon (forgot if he's pre-reg) then look under his hood, you'll see an identical trans.
THAT little project is a project looking for a home. I'm currently thinking of finding a 25 year old 323 and doing a complete Subaru drivetrain in it, with the rotary. Mazda has rallycross contingency now, but you need a Mazda car and a Mazda engine. I don't honestly think the RX-7 is at all competitive in rallycross. Fun, though.
If Paul shows up at the rallycross this weekend with his wagon (forgot if he's pre-reg) then look under his hood, you'll see an identical trans.
THAT little project is a project looking for a home. I'm currently thinking of finding a 25 year old 323 and doing a complete Subaru drivetrain in it, with the rotary. Mazda has rallycross contingency now, but you need a Mazda car and a Mazda engine. I don't honestly think the RX-7 is at all competitive in rallycross. Fun, though.
02-18-10, 09:07 PM
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You can get 15X8 Rota RB's in 4X110 for about $500/set shipped from 18racing.com. Don't know if the style is to your liking but that would let you put a wider tire on.
02-19-10, 10:51 AM
#20
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I already have a ton of 110mm wheels. I'm switching to 4.5" because I'm using FC suspension in the front for the larger wheel bearings. FB spindles are pretty weak, the spindles bent and then wheel bearing wear out rapidly and/or can not be adjusted.
If I was staying 110mm, then it'd be no issue. Have a ton of those wheels.
If I was staying 110mm, then it'd be no issue. Have a ton of those wheels.
02-19-10, 04:08 PM
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I already have a ton of 110mm wheels. I'm switching to 4.5" because I'm using FC suspension in the front for the larger wheel bearings. FB spindles are pretty weak, the spindles bent and then wheel bearing wear out rapidly and/or can not be adjusted.
If I was staying 110mm, then it'd be no issue. Have a ton of those wheels.
If I was staying 110mm, then it'd be no issue. Have a ton of those wheels.
they have 4x114, but i dunno about those offsets...
if you find a rota wheel you like lemme know, they sponsor us, so we get a deal
02-19-10, 07:04 PM
#24
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I have an eventual Plan where, if I'm making enough power that traction becomes a major issue, I figure that I'll start breaking rearends more comprehensively. When that happens, I'll sling an Explorer rearend under the car, put 5 lug hubs on the front, and use any of the multitude of cheap wheels available there.
My price point for wheels is under $100/set used, or $50-60 new. I'd rather spend my money on fuel and entrance fees rather than bling.
My price point for wheels is under $100/set used, or $50-60 new. I'd rather spend my money on fuel and entrance fees rather than bling.