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I just finished installing the Sun Auto Hypervoltage system and the Hyper Ground system. I believe the RX7 version is no longer made or at least not available anywhere in the US or Europe. I was able to find new old stock versions of both systems for a Nissan 350Z. I just modified the connectors by drilling them larger if needed. I made new ground connections between the battery, the Hypervoltage block, the stock frame ground, the alternator, and the lower engine block stock location with one loop. Another loop from the battery box (mine is aluminum), the Hypervoltage block, the throttle body and the UIM stock location. Another from the UIM to the firewall, another from the Hypervoltage block to the frame on the opposite quarter panel, and another from the UIM to the starter. Before starting I checked my resistance to all of these locations and at the Power FC grounds with the battery terminal as the base reference point and it ranged from 90 to 180 mOhms. After, 20 to 60 mOhms, a big difference. The most important thing was my Power FC voltage was 11.4 volts with the car off and the voltage at the battery of 12.6 volts. After the grounding, Power FC voltage was 12.45 with the battery again at 12.6 volts. What a difference!! Over 1 volt more. I don't really care if this affects HP at all, all I know is that every sensor and system in the car has to be performing better and more accurately especially with the addition of more stable voltage too from the caps in the Hypervoltage system and a buffering cap at the Power FC positive at the kickpanel.Mike
I remember someone on the PFC mailing list figured out that good grounds and a capacitor type voltage stabilizer actually picked up like 10-15 HP and had the dyno results to prove it.
I think the Sun Auto box could basically be replicated with some large capacitors, it's mainly acting as a fast voltage buffer.
Dale,
I agree. You could do a DIY kit with some high quality wire and a parallel array of low ESR caps. The Sun Auto was the only commercially available kit that seemed to work well (the cheap kits are crap from my research). The Sun Auto grounding wires are high quality 99.9% copper, look cool(bright blue), and are shielded for low EMI. Both Sun Auto kits cost me $240 total. I probably could have made DIY kits for $125-$150 after getting all the wire, connectors, and caps. No brainer for me for $100 more to get the commercially available kit.
Mike
Last edited by mikejokich; 02-18-19 at 02:27 PM.
Reason: spelling
My car was purchased new by me back in 1994. I had the original stock grounds and the added ground along the UIM was added back in the 1990's from a Mazda recall, The only time the grounds were touched were from two engine swaps through the years. The car was in Chicago weather for 4 years prior to moving to Huntsville, AL in 1998 and has always been garage kept and rarely sees rain or bad weather. Despite all of this, the grounding system was poor as my pre-install and post-install numbers show. I just think the original grounding system was inadequate by more modern standards, particularly given the many mods many of us have added through the years and the added stress on the electrical system it causes. If anyone can pick up these Sun Auto Hypervoltage or Hyper Ground kits, if you can find any new old stock, I would recommend it.
Mike
Here are a few more details on the install. The Hypervoltage block has three extra grounding points. Use them if you can, The grounding points should be cleaned very well to include using contact cleaner or alcohol and use fine sandpaper or a small dremel wire brush to take off oxidized metal on the engine block and the main grounding plate at the strut tower or anywhere else. Also, I used CW silver conducting grease on all the grounding points. This is different than insulating dielectric grease. This promotes conduction and prevents corrosion and reoxidization of the metal and prevents moisture between the metals. This should not be used on higher voltage areas such as spark plugs and should not be used on multi-pin connectors since it will cause shorts if it runs to another connection. Make sure all of your grounds lines have slack to allow engine movement and won't rub on areas to eventually damage the wires. Lastly, I bought some gold plated battery terminals to allow better conduction and they look cool too. The positive fits under our stock metal positive plate from the fuse box connection next to the battery. I changed the negative terminal to a wing nut connection too. Here is the link to the battery terminals. Only $11.44 apiece. https://www.wiringproducts.com/gold-...-terminal.html
Ok, for the benefit of all the other dummies like me, what does a voltage stabilizer do?
And since it’s all about grounds, it seems like that exhaust to chassis ground cable just aft of the cat can get sketchy over time. IIRC it’s for the O2 sensor so if you’re open loop it probably isn’t a big deal. There’s also that ground bock in the hatch area worth checking.
I dunno the difference but out of curiosity i looked on croober and there are a number of the sun auto boxes for $20-$30
If they are Sun Auto boxes and look similar to mine they should be good. Many of the other don't work and supposedly use inferior high ESR caps, as per my research.
Mike
Ok, for the benefit of all the other dummies like me, what does a voltage stabilizer do?
And since it’s all about grounds, it seems like that exhaust to chassis ground cable just aft of the cat can get sketchy over time. IIRC it’s for the O2 sensor so if you’re open loop it probably isn’t a big deal. There’s also that ground bock in the hatch area worth checking.
Here are two automotive articles that review the Hyper Ground system and the Hypervoltage system. This explains the theory in both ideas. Interesting, the Hyper Ground article tested a slightly moded RX7 FD stock twin turbo that showed a gain of 15 whp at 6500rpm just from the grounding system.
This is quite interesting - I added 1 more ~6-ga ground cable a few months back and got rid of the 3K hesitation. I already had several add'l ground cables. We'll see if the effect lasts. Link: https://www.rx7club.com/3rd-generati.../#post12311488
This is quite interesting - I added 1 more ~6-ga ground cable a few months back and got rid of the 3K hesitation. I already had several add'l ground cables. We'll see if the effect lasts. Link: https://www.rx7club.com/3rd-generati.../#post12311488
Interesting! Can you elaborate on the chassis connection point that you used? Which cross member, exactly?
I just restarted the car yesterday after finishing a few other things but have yet to have it on the road due to days and days of straight rain. I have two new data points since the installation of the Hypervoltage and Hyper ground systems. My voltage readout on the commander from the Power FC shows 14.9 V at 1600 rpm and went down to 14.4 after warm up on a fully charged battery on a tender. That is much higher than my more typical 14.2-14.4 V prior to the grounding system. The starter cranked the car is a split second. It was unbelievably quick and sharp even for my old stock starter.
As for DaveW's success with his grounding cable solving the stock 3k hesitation, this makes logical sense to me, particularly after the early results I am seeing too. The old adage is "garage in, garage out". If we don't run our ECU's and the corresponding input/outputs sensors at peak performance with all the needed low resistance power they need to perform their task, how can we expect idea results. The cause of the stock 3k hesitation, to my knowledge, has never been determined, but common sense says it must be either or both of the typical two common denominators, fuel and/or spark. If the ECU, sensors, ignition, injectors,and fuel pump are allowed to achieve their design potential, they will. In this case, it may just be the pure power they all need. LOL
Mike
Last edited by mikejokich; 02-21-19 at 10:30 AM.
Reason: added one thing
Interesting. My car had some type of aftermarket grounding kit installed when I got it (just wires). One to the side of the block, one to the UIM, one around the strut tower and another I cant remember off hand. I had to move my battery during the intercooler install and the wires are now too short. I'm gonna see if I can move them around or reroute them to hook it back up. I didn't document any voltage before the change but now I can do a before ground and after. Curious to see if I get any changes.
FYI the 3000 RPM hesitation is a bug in the stock ECU with the injector staging (secondary injectors coming online). I've driven cars with BAD 3k hesitation, like throw you through the windshield when the car was cold.
Swap in a PowerFC with no other changes done and the 3k hesitation is TOTALLY gone.
The grounding does help, I don't know if doing a full ground kit on a stock ECU car would help. Again, at the end of the day it's a stock ECU bug. The 96+ ECU's don't have that problem either (but they have a whole different harness and everything).
FYI the 3000 RPM hesitation is a bug in the stock ECU with the injector staging (secondary injectors coming online). I've driven cars with BAD 3k hesitation, like throw you through the windshield when the car was cold.
Swap in a PowerFC with no other changes done and the 3k hesitation is TOTALLY gone.
The grounding does help, I don't know if doing a full ground kit on a stock ECU car would help. Again, at the end of the day it's a stock ECU bug. The 96+ ECU's don't have that problem either (but they have a whole different harness and everything).
Dale
For anyone who is also in the Yahoo RX7 tuning run by Raymond(arghx), Xavier is a very knowledgeable guy who posted some very interesting discussions on the effect of ground resistance and power fluctuations on the ECU's and in particular the injector driver chips. If he reads this post, he should chime in. He has an electrical engineering background, I believe, and to summarize he states that poor power leads to poor injector transitions at the chip level, i.e., more sine wave type response vs. more ideal pure square wave response. The injector doesn't snap on but opens a few milliseconds later with more of a sine wave. This, at least partially, can be responsible for poor injector transitions. It would again therefore make sense that supplying the stock ECU with high frequency low resistance power could help and even maybe solve the 3k hesitation. Others running the stock ECU should chime in like DaveW did, and if anyone installs the two systems I just added, let the rest of know what happens.
Mike
One more data point, a very subjective one. I had the car out last Sunday for about 15 minutes and the car runs subjectively different. The way I would explain it is much smoother. It idles tighter with less small hiccups and the acceleration is smoother or more refined feeling, kind of like a glass of fine champagne like Dom Perignon vs. a glass of average champagne. Lol. I know some will say I am crazy, but there is a noticeable difference in drivability.
Mike
Last edited by mikejokich; 02-28-19 at 10:17 AM.
Reason: grammar
Interesting. My car had some type of aftermarket grounding kit installed when I got it (just wires). One to the side of the block, one to the UIM, one around the strut tower and another I cant remember off hand. I had to move my battery during the intercooler install and the wires are now too short. I'm gonna see if I can move them around or reroute them to hook it back up. I didn't document any voltage before the change but now I can do a before ground and after. Curious to see if I get any changes.
i looked through some of my JDM Rx7 magazines, just for fun, but i did notice that Mr Fujita likes to use the grounding kits on his cars, even back in the 90's
02-18-19, 12:45 PM
