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It’s been a while since I’ve been on here, been too busy running my shop and whatnot to really focus on my FC build. I’ve spent the last six months or so gathering parts and prepping for this build, and just about have the motor pulled. I have some time now that things are slowing down for the winter, so I’d like to buckle down and hammer the motor rebuild out!
The car is a 1988 Vert with a bad NA motor. I actually have managed to scrounge up two other good motors and housings, a couple trannys, and a full rebuild kit from people in town who were junking their FCs. My thought process was, while I have the motor out, I might as well do a full build on it.
The motor base getting used will be the 6 port NA motor (I have three lying around), and my goal is to do a 10 second car. The original plan was to go with a full bridge, plus nitrous build, but something has had me taking a second look at that. I’m not concerned about the nitrous, or prepping for that, in fact, I’d almost prefer a nitrous build over a turbo.
My real question lies in the porting. Is a Bridgeport more suitable to this build than a semi-p intake? Or would it be better to go with a semi-p intake and a custom intake manifold?
I know most people don’t build the six port blocks, but I’m looking to do something new and work with what I’ve got around the shop. Anyone have any tips and tricks for optimizing the six port actuators? Seems like I can’t find the factory exhaust-actuated system anywhere.
Verts are heavy bro... not sure if your gonna get into the 10's without boost
Any idea how heavy they are without the top? This one is going to get a bunch of the interior stripped, and the top is going to get switched for a custom canopy built over the roll cage. Thinking it should weigh in at less than the coupe, but I know there’s a good amount of frame reinforcements too, which should be good for the power level I’m thinking of throwing down.
You’d be better off with a semi pp. nitrous comes out of the nozzle at -127 degrees Fahrenheit. This can lead to thermal shock fractures to thin bridges, depending heavily on nozzle placement and shot size
no matter what you’ll need a different manifold. The stock intake is far too long to be useful on either a full bridge or a semi-pp.
You’d be better off with a semi pp. nitrous comes out of the nozzle at -127 degrees Fahrenheit. This can lead to thermal shock fractures to thin bridges, depending heavily on nozzle placement and shot size
no matter what you’ll need a different manifold. The stock intake is far too long to be useful on either a full bridge or a semi-pp.
that’s what I was thinking. The real question, with a semi-pp, what sort of manifold is the best way to go? With the nitrous you generally want to stay EFI in my experience. I’ve got all sorts of intake manifolds and things I can use to fab with, just curious how everyone else works it. The stock throttle body is probably worthless for high HP builds?
10 seconds needs about 400HP, slicks, and a good launch.
Full peripheral port with the appropriate amount of nitrous.
This will be a dedicated drag car if kept NA.
holy cats! It’s Aaron Cake himself! I’ve followed your builds and advice for a long time on my rotaries, I appreciate your input!
Definitely going to be a dedicated track car. I’m ready to pull the motor and definitely leaning towards a Peripheral Port. What’s the advantage of going full vs semi PP?
Updates! Easy week at the shop, got one of my spare motors broken down, got a machine shop on board with the porting, and now I’m just waiting to pull the motor that’s inside the car.
got this bad boy coming in this weekend, so not sure how much more I’ll get done.
holy cats! It’s Aaron Cake himself! I’ve followed your builds and advice for a long time on my rotaries, I appreciate your input!
Definitely going to be a dedicated track car. I’m ready to pull the motor and definitely leaning towards a Peripheral Port. What’s the advantage of going full vs semi PP?
More airflow basically. Above 300HP is possible NA with a full peripheral port and good tune. And in the scheme of labour, it's not much more work to go full peripheral vs. semi-PP anyway from a housing machining standpoint. It means going to a custom intake vs. modifying a stock intake but that custom intake boils down to 2 tubes w/injector bungs and throttle bodies.
I got the Mustang all finished, and tackled a G35 as well this week:
After that, I got the motor that was in the car pulled and into the shop, I also sorted parts for the disassembled engine, and began disassembling the third engine. As of right now, I know I have at least one set of usable housings and four more that I haven't gotten far enough to see yet. I have three complete motors worth of all the other parts as well, plenty for some experimentation!
As of right now, I'm leaving town for the holidays, so I won't make a ton of progress until the new year. That said, since I'll be at the in-laws, I'll have plenty of time to get a solidified game plan down for the rest of the build.
Originally Posted by Aaron Cake
More airflow basically. Above 300HP is possible NA with a full peripheral port and good tune. And in the scheme of labour, it's not much more work to go full peripheral vs. semi-PP anyway from a housing machining standpoint. It means going to a custom intake vs. modifying a stock intake but that custom intake boils down to 2 tubes w/injector bungs and throttle bodies.
Aaron, I see what you're going with here, and it makes a lot of sense. The machine shop already agreed that regardless of diameter, they can do the port work for a pretty reasonable price. I think I can do the sleeve install, because it's basically the same as the doing the semi-peripheral port. I've got a few questions as far as the execution goes. First off, what's the best way to have them drill the port as far as timing goes? I know with the semi-peripheral ports, usually they just get drilled planar to this spot on the casting.
Is that still the best way to drill the port? Or is it better to drill it at an angle to adjust the timing? And then once it's drilled, should the hole be countersunk and threaded for the sleeve? Or is it better to just insert the sleeve all the way into the housing, smooth it down to match the inside, and then devcon the whole slot?
Also, I suppose it's time to do some research on intake manifolds. For the semi-peripheral port, the plan would be to utilize a cheap LIM and mount it to the upper intake manifold, and use 800cc primary and 1600cc secondary injectors. But, with a peripheral port, would it be better to stay EFI or switch to individual carbs? And, there's really no point to keeping the other ports open, so I would have to devcon those shut as well. Mocking up a manifold should be pretty simple, really with the Peripheral ports, the difficult part will be figuring out a relatively inexpensive throttle body and injector setup.
Alright, so not a ton of progress, but I’ve definitely settled on the peripheral port, it’s going to be better suited for the build goals. This car won’t be driven on the streets much, so I’m not too worried about noise and driveability.
Still haven’t decided anything as far as timing goes, but I’ve been digging through Mazda’s old PP build SAE papers and there’s tons of good information there. Probably going to stick with a O shaped port, for ease of use, and I’ll have the machine shop thread the hole in the housing. This should allow me to thread the aluminum sleeve through the housings, and then Devon Aluminum in place for Sealing. Combining the two should make this a lot easier than trying to machine a press fit, but we shall see.
Intake and control is another area I’ll have to make some decisions on. Because this is a nitrous build, I’ll probably stick with EFI instead of carb, so it’s easier to pull timing and watch A/F ratios. I’m leaning towards the Speeduino system, as I’m more familiar with it than mega squirt and it has built in nitrous support. With that, I’ll probably switch to ITBs and a custom manifold. 2x 48 or 50mm ITBs should be more than plenty, if my reading is correct, since I will only have the peripheral ports and will not maintain the primary and secondary ports.
Yes, was about to say, check out Mazda's timing for the MFR peripheral ports. I think Mazdatrix has this info as well. Off hand I don't recall what the timings are.
Normally the sleeves are press it. Machine the sleeve slightly large, then freeze it and press into place. Secure with epoxy.
EFI for sure. No sense messing with fiddly mechanical parts when an EMS can control everything.
I'm back from vacation and finally have a plan all put together!
Biggest physical update: I got the old motor pulled, so that makes a total of 3 6-port motors sitting in my shop. The first was purchased disassembled, and has good housings. The second, was given to me because the old owner didn't know what it was worth and it wouldn't turn over. This one was disassembled, and it turns out its a good motor! Absolutely beautiful inside, minus the mouse nest. Heck, even most of the seals and springs appear to be good, I haven't had a chance to check clearances and whatnot, but most look reusable, despite the fact that I won't be using them as I have a full Atkins master rebuild. The third motor is awaiting disassembly.
Alright, now the plan moving forward...
Intake: We're going to run a super simple trumpet intake for now. Straight out the hood, and optimized for whatever RPM we're hoping to launch at. Eventually I want to do a sliding intake like the 787b. It doesn't seem unfeasible, and I have the parts on hand to design something like that.
Throttle: Since this will be a dedicated track car, I'm planning at running at WOT more often than not. I'm going to design a slide throttle based off of plans found at (Join). Should be incredibly simple, just aluminum and teflon, plus it won't lead to any blockages in the intake stream.
Engine: Full peripheral port! I have an Atkins Master rebuild kit with all new bearings, seals, springs, and the like. Right now, the biggest debate is going to be deciding what timing to use. I found the MFR timing, but I also have heard that doing the peripheral ports at 80/80 intake/exhaust is a better option. I'd like to make peak power as early as possible, but need the free flowing peripheral port to maximize output with the nitrous. I would prefer not to have to do any sort of internal machining other than the ports, but I may have the rotors clearanced and the internals balanced while it's all apart.
Transmission: I have 2 good NA transmissions I'm willing to blow up trying, otherwise I am picking up a turbo 2 trans with bad 3rd gear synchros to throw in. I'm not concerned about the synchros, but while it's out of the car I may just rebuild it. And, it'll swap the t2 flywheel, clutch, slave cylinder, and run the auto driveshaft.
Exhaust: Custom headers that should dump as quickly as possible out the side or out the hood.
ECU/fuel control: We're going to run either a megasquirt or a speeduino setup, it just doesn't make sense to me to spend $1000+ on an ECU when there are good options for less than half the price that do everything we need. Plan will be to run 2x 1000cc injectors, unless we find we need more. They'll be mounted like the 787b with the peripheral injection.
Nitrous: Nitrous control will be build in from the beginning. Goal is to run as much nitrous as physicaly possible, to make up for the extra weight of the convertible chassis. Using some online 1/4 mile ET by weight and HP calculators, for a 3000lb vehicle to break into the 10 second area, I'll need at least 450 whp. And if a peripheral port can realistically put down almost 300, that's a 150 shot of nitrous, minimum. There is of course going to need to be some weight reduction, and there will be lost time due to personal driving ability and the fact that we're working with a manual transmission. I'm not against the automatic, just simply prefer driving a manual. So, extra nitrous it is.
Engine: Full peripheral port! ...I found the MFR timing, but I also have heard that doing the peripheral ports at 80/80 intake/exhaust is a better option.
Transmission: I have 2 good NA transmissions I'm willing to blow up trying, otherwise I am picking up a turbo 2 trans with bad 3rd gear synchros to throw in. I'm not concerned about the synchros, but while it's out of the car I may just rebuild it. And, it'll swap the t2 flywheel, clutch, slave cylinder, and run the auto driveshaft.
Mazda used at least 3 different MFR ports, the early port is the Rx3 style, its round. the early Rx7 has the same port timing as the Rx3 port but its D shaped. this is what you're finding as the MFR timing. for the R26 engines they revised the port timing, and this is where the 80/80 port comes from. its wider too and will make more power. they also played with the intake lengths and diameters to optimize things. its all in SAE 900032.
for the trans you might want to start with the NA stuff, a healthy PP will destroy the turbo trans, plus the turbo trans takes 80hp to spin, and the gearing is just wrong for a PP
Mazda used at least 3 different MFR ports, the early port is the Rx3 style, its round. the early Rx7 has the same port timing as the Rx3 port but its D shaped. this is what you're finding as the MFR timing. for the R26 engines they revised the port timing, and this is where the 80/80 port comes from. its wider too and will make more power. they also played with the intake lengths and diameters to optimize things. its all in SAE 900032.
for the trans you might want to start with the NA stuff, a healthy PP will destroy the turbo trans, plus the turbo trans takes 80hp to spin, and the gearing is just wrong for a PP
I appreciate the input! That was part of my thought process, maybe it's better to run the NA transmissions into the ground, it's not like they're worth money and it's good practice while I get the rest of the drivetrain sorted. I took a look at that SAE paper, and that's the port we're shooting for! Hopefully will have the housings drilled soon, is there an easy way to mark the timing on these motors? A template or something?
I appreciate the input! That was part of my thought process, maybe it's better to run the NA transmissions into the ground, it's not like they're worth money and it's good practice while I get the rest of the drivetrain sorted. I took a look at that SAE paper, and that's the port we're shooting for! Hopefully will have the housings drilled soon, is there an easy way to mark the timing on these motors? A template or something?
12-08-19, 10:30 AM
