KahnBB6

iTrader: (5)

I have tried Optima Redtops in the past and have been let down too. At least where I am Interstate AGM batteries (the MTX models) seem to be the best bet. I'd love a better option just the same as you though.

Yes, I read your message and saw that you did the trial and error method of finding the right spring. I'm glad to hear it has held up for 2+ years! I'll follow up in PM about that further. Now that I have a good boost gauge to see my actual and accurate boost pressure I can be sure I won't adjust it to boost TOO high on that waste-gate.

A "smedium" size single does wonders for these cars! For this one SC I am sticking to the stock twins but long term I'm still planning to get into the STU Hybrid GT28's Can't right now but that's my plan. Also BNR Supercars apparently makes brand new front wastegate and rear transition actuator for them (albeit which requires a boost controller on the #1 to use). Newer parts with better flow are appealing. But for sure a modern single setup will be far cheaper and simpler and it'll use much newer technology.

gerrb

iTrader: (34)

Optima Red Tops ??? Been let down with those batteries. You can't let a car sit often with AGM technology batteries at least in my case the Red Top. Barely a year old, probably my fault since I seldom use the SC . Now it is a door stopper in my garage store room . I now use cheaper Walmart sold batteries .. hahaha , on my SCs and stays longer charged even if car isn't use.

RudysSC

Craig - good to hear my friend! I'll be super curious how it goes for you but if it goes as smoothly for you as it did for me you shouldn't have any problems!

Gerry - I'm in the same boat now my friend! Granted, my car hardly sits for more than a week... Granted - damn batteries are expensive these days!! I remember buying $100 batteries for Civics when I was a teen lol.

KahnBB6

iTrader: (5)

Gerry-- Yep. Optima Red Tops are both expensive and usually a letdown before they have aged reasonably. Hey-- at least your old Optima is still working for you in some way now! Winter time I'd expect your SC driving to drop off for sure. I keep a battery tender nearby if I ever need it for mine.

Rudy-- I will update you soon on the spring mod combination I'm using. Just hoping I can have another good afternoon or night free to fiddle with its installation before Christmas. I just barely got my new boost gauge install project squeezed in. Busy time for us all!

gerrb

iTrader: (34)

Still can get not so pricey batteries for our car at Walmart. Three of my SCs , have walmart batteries , one had been there for two years , and the other two 6 months .. no problem so far . I believe I bought them at $98 a piece. Optima Red , not even a year !

gerrb

iTrader: (34)

can't have 5 battery tenders , one for every boosted car of mine ... and winter is around the corner . Cold weather makes it worse for batteries of cars that are not used daily.

KahnBB6

iTrader: (5)

I 100% agree. It's just not feasible most of the time to keep battery tenders on them all. Maybe with a large garage but even then...

I bought the more expensive Interstate MTX model AGM chemistry battery with a lot of cranking amps because of winter cold conditions. Even in Florida we sometimes have our cold snaps and I have had regular battery chemistries treat me poorly when it really counted.

However I admit that it is hard to argue with the band for the buck value of Walmart batteries of any type: highly convenient, more affordable, easy to bring in and get replaced within the coverage period.

Here is hoping a couple of your SC's get even just a little winter driving time For what it's worth I have been far more willing to take mine out in regular rainy weather here ever since I switch to a set of really good high performance all-seasons. I NEVER thought I'd trust A/S tires but this model is excellent in the dry and wet.

I'll bet you could have some more fun in GA winters with one SC at a time if you had one set of high performance winter tires on its own set of wheels! Keep them until winter time and then swap them on to whichever SC you want to drive over the season.

Now anywhere there are road salts applied... that's a totally different risk that is never good for classic cars.

CLass of 1

I invested pretty heavily into a Braille AGM battery with my RX7, after an Odyssey battery failed on me. It worked great for about six months, then the engine lost compression haha — can’t be certain how long it would have been good for. But, I had a kill switch that disconnected the battery, really just a breaker, every time I turned the car off. So, I’m sure that helped a bit with the battery’s life.

Nick

RudysSC

Ok guys - I need a little help from y'all as I'm having some issues tracking down what's going on with my 2JZGTE VVTI swap. I started it ok this morning, and then all of the sudden it started choking on itself, missing, and idling low (all while running SUPER rich - like spitting out black smoke if I gave it any gas rich). I shut it off, re-started it, and it drove totally fine. I made a few pulls in it and no issues. Later on, it started to miss/hesitate/pop a bit while in light or full throttle as soon as boost started to come on even in the slightest. This has been intermittent and does not happen every time I drive it, however, it's basically every other time now. I have no CEL (I still am uncertain how the oem jdm supra 6-speed edu deals with diag codes and whether or not it spits back any real info when using the jumper wire diag trick). I got it into work and as I pulled into the lot it went into limp mode (No CEL, however, it did the gas pedal thing where only the last 20% or so of the pedal travel engaged the throttle).

I'm at a bit of a loss... I have some fresh plugs sitting around, and based on it missing and spitting out fuel my first thought is maybe I have a coil or two starting to fail? It may also explain the miss/hesitation under partial and full throttle as boost starts to come on (as you power through it however, it will build boost and pull hard after the hesitation).

Any input would be so greatly appreciated! The Japanese ECU makes this car quite hard to diagnose and it seems like the jumper wire trick on an OBDI car doesn't provide any accurate codes. But if I'm naïve please fill me in LOL.

Thanks guys - I always look forward to hearing your thoughts!
Rudy

joewitafro

I would get a JOBD compliant ecu scanner if you have an odb2 diag port. For some reason I keep thinking this sounds similar to the vvt-i throttle body motor failure i was dealing with, which also was intermittent but got worse over time and would throw me into limp mode at the end quite often.

VVT-I coils are also quite sensitive to cracks, inspect them thoroughly but buying a brand new denso set is pretty cheap and worth having around anyways. I also did this at one point after my swap when dealing with misfiring during load.

Rcreegan

iTrader: (2)

Rudy pull the ecu apart and look for leaky caps as well. If you don’t know what your looking for shoot me a pm and I can walk you thru it

scsexy

iTrader: (1)

^^ probably the ecu bud =\

KahnBB6

iTrader: (5)

Rudy, I'm going to add to the chorus that you should probably pull out your JDM ECU, remove the covers and inspect it for any blown or leaking capacitors. I am going to be doing the same with my own ECUs soon (sorry I haven't replied to your comments in my thread yet-- I haven't had time yet to dive back into it).

In your case it may be as simple as just needing new caps. Also joe's caution about the VVT-i coils and cracks is easy to investigate.

Here are two tutorials I am going to re-watch soon for my own learning as I inspect my spare ECUs. They may be useful to you too. On of them never had its capacitors replaced so I may consider doing it myself for once rather than sending it in to someone else. If you decide you may want to do any cap replacement service yourself... only order new exact brand and value capacitors from either Digi-Key or Mouser Electronics. They are the most trusted genuine suppliers for the real McCoy in the U.S.

You'll also need a digital control temperature-adjustable ESD safe soldering station (I recommend a Hakko FX-888D model), a twin filter N95 respirator from a hardware and home improvement store (for your health safety... there is NO reason to breathe soldering fumes directly, period. Don't skimp on this.), and some 7mil nitrile gloves (Harbor Freight)... plus the solder and flux recommended in the videos.

For desoldering you should buy a desoldering strap and also a Velleman desoldering sucker ($15 on Amazon). There are professional desoldering guns also but they are $200 or more by themselves-- overkill unless you do this often.

Pay particular attention to the plastic scraping tool this technician uses and his method of loosening the factory sealing paste. You want to avoid deforming the metal lids when removing them. Also wear an anti-static wrist strap connected to a good mental ground just for good measure to protect against electrostatic discharge once you have the ECU boards open. This really is no different once inside than working on any vintage 80's-90's personal computer motherboard... but since these are so pricey and proprietary don't take any unnecessary chances.

Some good techniques are discussed in the second video and also in the comments for it directly on youtube.

RudysSC

Wow - thank you guys for the responses and for your input! I did have a local guy replace caps in my JDM ecu a little over a year ago. I'm hoping his repair will last and will be sure to double check that! I did go ahead and order new Denso coils, NGK wires, and have a fresh set of plugs set aside as well. I'm going to start there, check the ECU, and cross my fingers my dumb VVTI throttle body (I'm on my second already....) can make it through another year!

Not sure when I'll have a chance to spend a bit of time with it but I'll post an update ASAP. Thanks again for the input guys. If I were to need another ECU repair - I know Tannin won't mess with the JDM ones. Do you guys have any other recommendations?

KahnBB6

iTrader: (5)

Tanin will not work on JDM ECUs? Hmm. In that case I would say to try SIA Electronics instead.