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^This, the POR15 degreaser product (used to be called "Marine Clean") is my go-to stuff for all the tough cleaning & degreasing jobs, always have a gallon of the stuff handy in the shop. In addition to a pressure washer, one of those portable steam cleaners like this basic Harbor Freight one also works wonders - https://www.harborfreight.com/1500-w...kit-63042.html
Project FD RX-7 Restomod: Part 6 - Antigravity and Mele Design Battery Relocation
We just made one of the best battery relocation kits for the FD RX-7 with Antigravity, Mele Design Firm, and Battery Cables USA!
There are many reasons why relocating the battery should be one of the first modifications done to an RX-7. First off, electronics hate heat and there aren’t many engine bays that get hotter than one with a rotary engine. Batteries will last longer and the car will start more reliably if it is not heat soaked in the engine bay. Secondly, moving a heavy battery from the front of the car to the middle or rear will improve the car’s weight distribution, steering response, handling, and grip. It also removes a bottleneck behind the radiator to improve airflow as well as allow for more room in the engine bay for cooling upgrades like a bigger intercooler.
In the article:
-Antigravity & Mele Design Battery Relocation Mounting
-Battery Cables USA FD RX-7 specific Relocation Wiring Kit - Cable Routing
-Battery Cable Size Information -Battery & Tray Removal -Gutting Battery Power Harness -Replacement of Engine Bay Cables and Ground Wire
Nice install, I appreciate that you upgraded the alternator wire and re-wrapped the original harness. It would be cheap insurance to add a few boots/covers on the 12V wires near the battery, breaker, and starter: https://www.prowireusa.com/c-208-battery-boots.html
I disagree that rotary engines are hard to start. My car had a PC680 battery in the stock location years ago when I used it as a daily driver, and it served well for about 3 years. It has a Miata AGM battery now, and planning to relocate to the spare tire area someday because I'm not willing to give up space in the storage bins. ECU logs showing cranking RPM would be a good way to test or demonstrate how well the old vs new setups are working.
I'm curious why too, but there's nothing inherently unsafe about it. The wire is sized to handle over 200A so having a 200A breaker at the source isn't dangerous in any way for the run from the battery to the starter. The starter itself is wired directly to the battery in stock configuration, so this is equivalent and safe (even if not necessary). The 2AWG from the starter to the fuse box is also sufficiently sized for 200A. From there the 120A fuse protects downstream. Purely from a circuit protection perspective, it's fine. But I'm also curious why the 200A.
Something I just noticed however, the fuel pump wired directly to the circuit breaker is concerning. You've got some length of very thin wire unrated for 200A effectively in a circuit that could see up to 200A. I'd do a circuit breaker as close to the battery terminal as possible and that connected to a fuse block in the bin with appropriately sized outputs for those two (or more, maybe future additional circuits) branches to fully protect everything.
they ran the wire from the starter to the fuse box because they dont have a power wire at the fuse box at all. they did it battery---->starter----->fuse box. normally people go fuse box-----> battery----->starter or run the starter wire directly to the fuse box. i ran my alternator and starter wire to the fuse box and then the main power wire from the battery to the fuse box. battery------>fuse box----->starter/alternator.
so the starter is now in series with the entirety of the electrical system. seems like not a good idea. i cant think of a reason why but it just doesnt make any sense to do it that way. the real issue here is that 200A breaker will not pop. the fuse at the box will pop before that one will. its acting as nothing more than a kill switch with an unreachable amp load. my rule of thumb is to match the breaker with the alternator. using the factory breaker size makes sense as well and is typically the same size as the alternator already
Thanks for the questions, I hope this helps to clarify a few things:
The decision for the 200A circuit breaker was for the unlikely event that the 7' power cable to the starter motor is cut and grounded to the chassis. It's actually unnecessary since there is no circuit breaker or fuse box between the factory battery and the factory fuse box or starter motor. The location of the circuit breaker in this battery relocation system makes for an easy way to disconnect the power to the entire car when working on it and for long periods where the car is not driven.
In the factory layout, the starter motor is always directly connected to the battery (both are on the same side of the factory fuse box). Therefore, running the (relocated) "00" battery cable directly to the starter, and then the 2AWG cable from the starter to the fuse box will be no different from stock from an electrical standpoint. It also makes the layout a little simpler and cleaner than running a cable from the battery to the fuse box and then a cable in parallel back to the starter motor. You can, and it's only a couple feet of overlap, but why do it when it's electrically no different and less cables...
If there happens to be a significant amp draw on the system, the factory 120A fuse will work as intended and blow. If there is a significant amp draw from say the starter motor failing, that amp draw will not draw current from the 14awg fuel pump wire (which is no different from running the wire directly to the battery), and that circuit is protected by a 40A fuse so there is no risk of an issue there either way.
The electrical load of the car will likely be higher than stock with the new igniters, fuel pump, radiator fans, and stereo system. A 180A alternator will be installed in the car, so having a circuit breaker lower than this at 120-150A will likely trip all the time when the increased demands of sources directly connected to the battery (fuel pump, fans, stereo) will be higher than the current draw through the 120A main fuse. This also gives some headroom if I decide to go to an electric water pump in the future.
dont want to spiral into an electrical conversation but............... i think my understanding will only benefit from doing so.
there is no fuse box BETWEEN the factory battery and fuse box because the battery terminal IS the fuse box. starter circuits in general arent fused. running the wire from the starter to the fuse box is not the same electrically as stock. its series vs parallel. power has to go through the starter to get to the fuse box where as in stock form, this is not the case..... series vs parallel. like i said though, i cant think of a reason why this wouldnt be a good idea but something about it seems off.
with everything running full song you better not see anywhere near 100A during operation otherwise you have a problem lol. you may be grossly overestimating the electrical demand of the car even with aftermarket parts. even accounting for an audio system youre not going to be pulling so many amps that youll need the headway of a 180a alternator. sound systems run in parallel anyway and have a breaker of their own so the stock main fuse in addition to the one at the battery arent affected by whats going on there. even if there was a large draw, the breaker for the sound system will trip and kill it.
obviously the way its set up works but the logic going into it seems to be misshapen. also not saying this simply because ive never seen it done this way before... its just from a technical stand point, it doesnt seem to make sense with the given logic as to why it was done
I also ran power directly from the battery to the starter.
However, I never ran another power line from the starter to the fuse box thingy up front. Seems unnecessary.
Why do the alternator to fuse box?
I replaced and upgraded the factory power line from the starter to the fuse box with 2AWG cable. I also replaced and upgraded the factory alternator (to fuse box) wire with a 4AWG cable. I apologize if that wasn't clear in the article.
Originally Posted by cr-rex
there is no fuse box BETWEEN the factory battery and fuse box because the battery terminal IS the fuse box..
Correct, the positive terminal of the factory battery is directly connected to a plate that connects to a cable going to the starter motor and another cable going to the alternator. This factory layout means the starter and the alternator ALWAYS are directly connected to the battery.
Originally Posted by cr-rex
running the wire from the starter to the fuse box is not the same electrically as stock. its series vs parallel. power has to go through the starter to get to the fuse box where as in stock form, this is not the case..... series vs parallel. like i said though, i cant think of a reason why this wouldnt be a good idea but something about it seems off.
Running the battery positive cable to the positive post on the starter and then another cable from the positive post on the starter to the fuse box IS in parallel (and not series) -and electrically the same as stock. In order for something to be in series, the positive wire needs to connect to the negative side of the electrical device.
Originally Posted by cr-rex
with everything running full song you better not see anywhere near 100A during operation otherwise you have a problem lol. you may be grossly overestimating the electrical demand of the car even with aftermarket parts. even accounting for an audio system youre not going to be pulling so many amps that youll need the headway of a 180a alternator.
Have you built many 600whp+ track cars? A 700whp EVO with EPAS that I tested was pulling well over 100A continuously.
Running through some numbers:
ECU & Injectors - 10A
Ignition coils - 30-40A
Fuel pump - 20-30A
1-2 High-output Radiator Fans - 20-50A
Electric water pump - 8A
Stereo?
Conservatively 80A and upward of 120A+ is possible at redline. A 180A alternator ensures there will always be enough current for anything I throw at it although any of the 120-140A upgraded alternators might be more than enough.
Originally Posted by cr-rex
sound systems run in parallel anyway and have a breaker of their own so the stock main fuse in addition to the one at the battery arent affected by whats going on there. even if there was a large draw, the breaker for the sound system will trip and kill it.
If the car is drawing more amperage than the stock 90A alternator is putting out, there will not be enough power for the fuel pump to maintain the pressure and AFRs that are required. It's important to have enough headroom where the current does not drop under heavy use.
Originally Posted by cr-rex
obviously the way its set up works but the logic going into it seems to be misshapen. also not saying this simply because ive never seen it done this way before... its just from a technical stand point, it doesnt seem to make sense with the given logic as to why it was done
It's been done countless times before for over 15 years now. Unfortunately most of the photos are no longer hosted.
I like what Howard Coleman has done for the community and hope my project becomes another great source for the community and for those modifying their cars.
running the wire from the starter to the fuse box is not the same electrically as stock. its series vs parallel. power has to go through the starter to get to the fuse box where as in stock form, this is not the case..... series vs parallel. like i said though, i cant think of a reason why this wouldnt be a good idea but something about it seems off.
Running the battery positive cable to the positive post on the starter and then another cable from the positive post on the starter to the fuse box IS in parallel (and not series) -and electrically the same as stock. In order for something to be in series, the positive wire needs to connect to the negative side of the electrical device.
Yup. Running the positive battery cable directly to the starter is 100% electrically equivalent to running it directly to the side of the fuse box.
The metal bracket on the side of the fuse box is a single piece so the power (from the positive cable on the right below) will go directly to the starter via the factory harness (on the left).
I ran the power cable directly to the fuse box because it was easy to route it along existing factory wiring.
The breaker is definitely required since you do not want an unfused cable, particularly one that can dump a massive amount of current. As mentioned, the factory layout does not need one because the battery positive terminal is directly attached to the fuse box bracket. (That said, the factory line from the fuse box to the starter is effectively unfused, though it runs for a short length inside the engine bay - not through the cabin.)
FYI, the original battery relocation post has been updated with a PDF so the write-up should be easier to find. (Thanks, Alberto!)
Looking back, I am not so fond of the involved in-cabin routing of the power cable. I think running the cable along the driver door sill would be a little nicer.
BMWs (which usually have trunk-mounted batteries) route the power cable that way.
Also worth noting that modern BMWs with trunk-mounted batteries have a battery disconnect mechanism that activates in a crash:
When I did my battery relocation on my RHD, I ran the cable through the LH wiring in the engine bay. It was connected to the fuse block as above. I then ran the cable through the fender, into the grommet on the LH side. I ran the cable along the LH door sill, using welding 0 AWG wiring. I wrapped the wiring again in protective sheathing. From there ran it into the bins. It was super clean. You can't see one bit of wire. It also felt to be the safest way since the door sill has some framing that allows you to pass it easily under the carpet.
Driveshaft failures are extremely uncommon, and if it happens, it's still unlikely to cut the battery cable the way I routed it in the tunnel.
A fender bender that shifts the fender could cut the line routing it that way, but that's also unlikely. Overall, I think the tunnel is the safest place for the battery cable, it's also the shortest, which is why I chose that. But the fender routing isn't practically much different.
Project FD RX-7 Restomod: Part 7 -McLeod RST, the Ultimate Streetable Twin Disc?
We are installing a much-needed clutch to the RX-7 community that has 800hp of holding capacity and organic discs for chatter-free, OEM-feel and effort.
For Project Restomod RX-7 we are taking a somewhat different approach to modding a car. We are striving to refine and elevate the FD RX-7 in every way to better than OEM levels by using modern technology, materials, and my experience as a development driver for major OEMs. A good example of this would be in our clutch choice. Since we are planning on making more than double the stock power output, a significant upgrade in clutch holding power is going to be needed. Of course, a stiff and heavy clutch with a light switch engagement isn’t going to be acceptable. We reached out to our friends at McLeod Racing for a clutch solution that will be able to handle the power while keeping things drivable with smooth engagement and a light pedal.
Very cool, Billy. Have been away for a while and hadn't seen your thread. I scanned it a few times and gone to your website. I'm a big fan of OEM-Plus builds and look forward to following it. Could you share your overall concept of the "Plus" in the OEM-plus? Great stuff.
MotoIQ and Coleman are legends in the tuning-geekery game! While I havent read this thread or motoiqs build, I just thought itd be fun to troll back over here on the boards to drop a post for ol times sake
Very cool, Billy. Have been away for a while and hadn't seen your thread. I scanned it a few times and gone to your website. I'm a big fan of OEM-Plus builds and look forward to following it. Could you share your overall concept of the "Plus" in the OEM-plus? Great stuff.
Hey! Give the intro article (#1) a read, but to quickly answer your question, I've worked on the development team for the new Ford GT and Shelby GT350 & GT500 road cars. I'm taking my OEM and racing experience and resources to carefully select components, develop new products, and test them in order to modify the FD to a level better than OEM (hence "plus") while retaining the driveability and refinement qualities that would be acceptable from an OEM standpoint today, unlike most tuner builds that use whatever is free or the norm to create a "racecar for the street" which rides harsh and beats you up over time.
Originally Posted by s1mpsons
MotoIQ and Coleman are legends in the tuning-geekery game! While I havent read this thread or motoiqs build, I just thought itd be fun to troll back over here on the boards to drop a post for ol times sake
🤙
Originally Posted by MWillzz
I did the battery relocation as well and turned out pretty good! I will be installing the LRB rear bin delete kit to clean up things a bit.
Have you driven the Exedy twin disc clutch?
I have that in my car and it is really nice. I did also add the FEED slave cylinder however which helped quite a bit too, the engagement is smoother and more consistent now.
how would you compare the Exedy and the McLeod clutch?
06-14-22, 05:48 PM
