86 GXL

I'd like it to be streetable and reliable when finished over big HP numbers...maybe 300-350whp on a conservative tune?

I've got a 1987 turbo block with bad oil seals that I will be rebuilding. I plan on doing a large street port on it as well.

The turbo I think I've decided on is a Holset HX35 with divided exhaust housing. Not much information on this turbo, the compressor maps I have seem to be just about perfect for a 13b. I'm wondering how much boost to run as well...

Manifold is up in the air yet, I'm considering making one myself.

Wastegate--I'm thinking of using a Tial 44mm to combat boost creep from a turbo capable of nearly 4 bar...

Fuel - Walbro pump, stock fuel lines. Will I be okay running 550cc/1600cc injectors, or should I get larger primaries?

Fuel control and gauges - Megasquirt. AEM Wideband. AEM Pyrometer. AEM Boost/vacuum gauge. AEM Coolant temp gauge.

 

Holset HX35 is a good turbo, but it is designed for a diesel truck and is thus most efficient at higher boosts . It's cheap though. I have done a lot of research on this turbo, as a friend of mine is going to be running two of them on a 3000GT for an 800awhp build.

There are no compressor maps that I have seen (I have seen maps for the HY35, THEY ARE NOT THE SAME THING), but from what I can figure out it is a 56 mm inducer w/ 83 mm exducer, thus 46 trim. Generally speaking, lower trim # equals designed more for higher boost (that's excluding all the other variables that go into a turbo's flow characteristics). A really common turbo is some kind of 60-1 https://www.rx7club.com/single-turbo-faq-122/60-1-specs-210078/ , which I think would be a little better for straight pump gas. You can do 300-350 easy on a 60-1, I did 386 on mine. 44 mm wastegate sounds good, rotaries are bad with boost creep.

If you want to go Holset, try a HY35. Those are the ones that were designed for the automatic cars and would be more responsive but flow less at higher boost. This is the compressor map I managed to find a while back: http://www.mygen.com/users/dbruce/my...003_vg30et.jpg . It's on a site for 300zx 's, but if I can read the grainy image well enough it appears to put out around 35 - 38 lbs/min at one bar of boost, and doesn't even hit peak efficiency until over 15psi, which is getting out of straight pump gas territory on a rotary. I imagine the HX35 is even more geared toward higher boost levels.

I've had bad luck with AEM electronics, but to each his own. The display on my AEM wideband went bad quickly and the tech support guys gave me the run around for many weeks. And I've had bad luck with their 0-5v output, as it is not a truly linear output (check the AEM forums for the polynomial function), plus many people have issues with electrical noise. Check the Power FC subforum for example. I could never get the AEM wideband to display correctly (would not agree with the gauge 100% of the time) on my Megasquirt even though I had wired in a common ground. But that was a couple years ago, so who knows.

I'm not sure about the AEM pyrometer, but you need something that can read up to 1800-2000 degrees, otherwise it will just peg. You can consider a digital 0-5v one: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/dual-digital-egts-612960/ that can be datalogged. Or the pineapple racing one is dual channel and reads up to 2000 degrees.

The Megasquirt is a good choice, but when they say "do it yourself" they aren't kidding. I had one on my nonturbo. Most tuners (such as Steve Kan) won't touch it, just keep that in mind. If something goes wrong you probably are not going to find someone (besides some people on here) who can handle both a Megasquirt and a rotary.

 

Thanks for that, at least I know I'm headed in the right general direction!

I was aware of the HY35, but wasn't entirely clear which would be better for my build, and you cleared that up. Between the HY35 and the HY35W (internally wastegated), I think I'm going to have to get the HY35W and weld it shut, I read something on the housing on the HY35 being too ridiculous.

My mistake, all electronics are Autometer, except for the wideband, which is for sure an AEM. I've had one in my other car for a few years with no problem, but never used the 0-5v output (obviously very important with the standalone). Thanks for the heads up, I'll do some reading on what to do with that. If I remember correctly, the pyrometer might top out at 1600*...eek!

I'm hoping to find one of the plug and play megasquirt kits. The reason I chose the megasquirt over a haltech is the same reason I chose the holset over a turbonetics...budget.

 

Get a power fc instead of a megasquirt. Then we can blow our cars up together trying to tune them

So what are your aspirations for an intercooler setup?? You should run a stock TMIC with meth injection and buy my TII hood for a super deal...

 

I thought the Power FC was only for FDs?

Definitely going with a big front mount, my bumper is already all chopped up from the previous owner and I'd rather not mess with meth injection or anything else at this stage...trying to keep it as simple as possible. I've already got two hoods for this car anyways

I do need some 550cc primaries, if you think those will work, I think you had some laying around?

 

I am procrastinating/skipping studying for my summer school exam so here is my [long] perspective on choosing an EMS:

First, there is an adapter kit for the Power FC from Banzai Racing. It should work fine on an s4 N/A harness, you just need to manually run a wire from the stock knock sensor to the ECU if you want to be able to log its readings.

Realistically if you want to run on a 2nd gen using the adapter kit and used parts while not buying a datalogit for self tuning, you are looking at $1000 for a Power FC, and then you have the cost of a tune. If you buy a datalogit (box that is needed for any real self tuning) that will cost you about $250-300 used, but then once you learn how to tune you don't have to pay anyone else to do it for you (especially if you are constantly trying new setups like me). There is a lot of information available for tuning the Power FC and the Haltech, as those are probably the most popular EMS's. I have owned a Power FC and a Megasquirt and have messed around with the Haltech, but I know only a little bit about Microtech.

Expect to spend like twice as much for any other standalone besides Megasquirt, but you will have much more support from shops and on the forums. It's a tradeoff that requires careful consideration. It's really a time vs. money thing, as the learning curve and potential problems are greatest with the Megasquirt given its smaller base of support, especially among high horsepower cars. I ran a plug and play megasquirt on my nonturbo a few years ago (the first-run Zeal units), but it was my first attempt at a standalone and I was just in over my head as the basemap did not work well for my heavily modded n/a setup. I never made any more power than I did on stock ECU (172rwhp vs 172rwhp) and ditched it. I've learned a lot since then though, and I tuned a Power FC myself to 386rwhp.

The Power FC was nice because it had such a great amount of support, such as the tuning guide you can buy from Chuck Westbrook (cewrx7r1) which also gives you access to the Yahoo! support group with some very knowledge people. But the Power FC has limitations. Its idle control capabilities are pretty crappy compared to other EMS's, but that's not a problem on every setup. The datalogit box gives you up to 8 0-5v inputs for logging, but there are no usable switched outputs for nitrous control or 2 step, nor does the PFC boost controller work well. There is a switch for an electric fan on the Banzai Racing Adapter harness though. The Power FC's closed loop capabilities are very limited as well and most people disable it.

What the Power FC does have over the other choices is the plug and play installation and solid base map. Either the supplied Banzai Racing map or the FD basemap (with the settings adjusted for the GM MAP sensor and your injectors) will get you started and running ok. The PFC also has a 20x20 fuel and ignition map which the Megasquirt definately does not have (at least not the MegaSquirt and Spark Extra I used) and some other standalones don't have either, depending which model you buy. The injector staging for the Power FC is very good as long as you use the proven settings that many people use (Chuck Westbrook's notes discuss this). 550/1680 is no problem and all the staging and flooding problems you ever had on a stock ECU usually go away with little fuss. The Commander handheld unit is a neat thing to have, as it can make small changes without a laptop and display peak boost/knock/rpm/etc, but it could be better as its features are limited and it has a dated 90's look to it. The datalog analysis program in the datalogit software is pretty good too once you get the hang of it, as well as the "map watch" feature which lets you see what kind of knock readings and AFR you are getting in a particular spot in your fuel map.

What you need to consider now is:

1. Who is going to tune the car, and what is that person most knowledgeable with? If it's you, how much patience do you have to learn? In terms of the tuning itself, I think you will get up to speed on the Power FC the fastest, the Megasquirt the slowest, and the Haltech or Microtech somewhere in the middle. The installation is an X factor. I had serious electrical noise problems on my Zeal Megasquirt which I never had on my Power FC, but both were plug and play units. Haltechs and Microtechs have a huge potential for problems if you are not really good at wiring.

2. What do you want your EMS to control? If you've got your heart set on a "do everything" box, the Power FC is not for you. A Plug and play Megasquirt won't do it either, as you will have to add in the features you want. You would be best with a Haltech or Microtech for that, depending on what model you get.

3. What is your budget? Remember the hidden costs of getting a car tuned and then retuned, of possibly having to replace all your OEM sensors if you go PFC or a plug and play Megasquirt. The Power FC adapter kit comes with IAT and MAP sensors, and I bought brand new OEM thermosensor and TPS. Standalones are much more sensitive to bad sensors or wiring than the stock ECU. That's one of the advantages to getting a system that replaces everything. If you get a Haltech, try to install it yourself, then screw it up bad, you will pay $Texas for a shop to basically redo it. So there are a lot of tradeoffs here.

I know that was a lot to throw out there, but you need to think carefully and do a lot of research before you buy an EMS. The Power FC was awesome for learning how to tune. Right now though if I had the money I would sell the Power FC and go Haltech, doing all the wiring myself, with the EMS controlling absolutely everything I can make it control. But I have the knowledge to do that now, and I most certainly didn't a year ago when I bought my Power FC.

 

I, too, am procrastinating a lengthy reading assignment (by doing lengthy reading, oddly enough).

I've never owned a boosted vehicle before (other than nitrous, meh), and I've only tuned on an SAFC-II, not a real standalone. (At least the PFC is Apexi, some things will be the same!) I'm biting off quite a bit here, and I guess #1 priority is to not blow **** up while keeping headaches to a minimum. If I have to budget in an expensive EMS, I guess I should.

The car has virtually little interior right now, and I don't plan on replacing it. Plans are "street legal track car". Thus, perfect idle, comfortable driveability, or a "dated 90's look" don't matter much.

I really like everything I'm reading on the PFC, except for the price...the stupid adapter kit is $215, $320 with the MAP sensor...add to the $850 for the ECU and $250 for the datalogit, and I'm nearing the budget I was planning to spend on the whole project. I would want the ability to tune it myself (which can be evidenced in the fact that I'm still considering the Megasquirt!)

One thing that I'd like to avoid (which falls into the headache category, I suppose) is messing with the ECU every time I sit down, like I usually have to do with the SAFC. I think pretty much any standalone will be a "tune it and forget it" kind of deal, but some may hold advantages over other ones.

I'm not afraid of tinkering...I'm still considering building the Megasquirt myself...I believe that to be within my range of abilities. I'm not afraid of reading and learning...but as you mentioned with the Megasquirt, the problem is simply that there is not much written on a beginner's level. This is a huge advantage to the PFC and Haltech.

I will really have to get 1000 miles on my rebuild before it can be tuned anyways, right? Maybe I should run a stock ECU until the engine is broken in, minimize the amount of things that can go wrong at once?

Something I've been thinking about. I have a handful of friends in the Saturn community running impressive setups on the Megasquirt that would be helpful, but only online. As far as locals go, I'd likely be taking it to a dyno, and I know some dynos won't touch the megasquirt. The dyno I took my last car to does not list a preference on their website, but they primarily do DSM stuff.

If I'm going to drop $1000+ on a standalone, then the price disadvantage behind the Haltech and Microtech are no longer an issue...but installation still is. I'm much less confident in my ability to wire up a whole harness then I am splicing in a megasquirt or plugging in a PFC. My wiring tends to get messy and hard to trace.

I would like to ditch the stock ECU, so fuel and spark. Other than that, I have an electric fan, but I just finished setting that up with it's own thermostat and bypass switch. Boost control would be nice, I suppose....that might be the only other thing I would need.


I originally planned on doing this whole project for $1600 or so, which I still think is reasonable....but if I don't go with the Megasquirt, that may end up doubling. I've been looking for a plug and play megasquirt for too long, I'm okay with getting a standard one and splicing it into the stock harness. (Seems no more difficult than installing a radio....colorblind) I am in Australia right now, the land of the Haltech, maybe I can save on shipping...haha.

If I had to sum up "Budget?" in one sentence, I'd say that I'm going to go cheaper wherever I can without sacrificing too much. If that means more reading, homework, legwork on my end, it means I have something to do in my free time!

I really just don't know...there's so many viable options and so many tradeoffs, as you mentioned. I've done a ton of reading and I still feel like I have no idea.

PFC vs. Haltech vs. Megasquirt....off to read some more. Is the $1300 I would spend on a PFC or Haltech worth the $1000 in headaches over a $300 Megasquirt?

 

Actually, there seem to be an abundance of haltechs for sale....for half the price of new....with terminated harnesses...that may be my best bet!