Always planned to go single turbo since buying my car as a roller, but now that I’ve gotten my engine back from the builder, I’ve started trying to do actual research into single setups. Between experiences with local cars, and reading several threads on here (mainly ones linked below), I think I’ve narrowed it down to two setups. However, the more reading I do, the more I realise I am out of my depth.

My goal is a fun but reliable street car that I would have no problem taking on long road trips. The current idea is to build everything for the low 400’s hp range, but run majority of the time in the high 300’s just to have a little overhead. Currently the engine is a fresh rebuild, new housings, superseals, and a mild streetport done by Kilo Racing. The PO already did a rats nest delete and installed Radium rails/pressure regulator, and 750 & 1300 injectors (cant tell the brand). This engine previously had a single on it, though I don’t know what specifically.

Given everything I’ve read, it seems like the two best options are the Turbosource 7670 and the 8374 kits. However every time I read a new thread I go back and forth on which one is right for me. I do have concerns with each setup and really just need a clear path forward. With the 8374, the difficulty with running low boost, and the overall higher power ceiling concern me on if it will be fine to run around the 350-400 range. I have some experience with the 7670 as several local guys run them, but a lot of them are considering upgrading.

Based on what I’ve read, I've put together a list on what seems to be the general mod spread for this kind of build.
https://www.rx7club.com/single-turbo...sults-1060852/

https://www.rx7club.com/single-turbo...esults-1118515

https://www.rx7club.com/single-turbo...ystem-1132306/

https://www.rx7club.com/single-turbo...tions-1171562/

https://www.rx7club.com/single-turbo...-fd3s-1171597/
Like I said, I’m way out of my depth, so I fully expect for stuff to be off, or have completely overlooked something. At the end of the day, I want a fun car that I can rack up miles on, but with a bit of pep. I’m not chasing big power, track performance, or 0-60 times.

Appreciate any advice or guidance.

 

I was in the same boat as you - didn’t care for track or drag times and wanted a reliable fun weekend car.

I’ve achieved it.

turblown 8374 kit. Get the external gated one as you’ll struggle to control boost with a street port.
haltech 1500 with IGN1A
turblown UIMLIM

all of my hot stuff is professionally heat shielded. I have a very efficient v mount setup and I’ve removed the Omp.

I’ve got a racing beat centre section and a Greddy comfort gts backbox. It’s perfect sound without being loud af.

it’s super reliable and fun, and don’t let anyone tell you the 8374 is too big or laggy or can’t run low boost. It’s absolutely perfect.

it’s making 470hp (UK hp, you guys in the US always seem to have more for the same setups) and is a dream to drive.

 

I assume your car already has basic bolt ons since its currently single turbo? Upgraded radiator and intercooler?

For the power level you are wanting, I assume you will keep it on pump gas. I would consider adding in an W/I system into the intake tubing with a low CC sprayer. This will help keep temps down and help to clean the motor. On my current setup, I tuned for the boost level I wanted, then added the W/I after tune as an added measure.

 

7670 or 8374 will get you there ...
8374 is a great option, i was using it for years and i really like it. I would look into the 8474. I have not used the 8474 but on paper it looks ideal.
it really depends on what you are trying to achieve but for me personally the 7670 is a little small. Not much room to grow when you want extra power..

I have been plenty happy with the stock crank trigger. I don't see the need for the "improved" crank triggers .

as for the fuel setup. i used a variety of setups. from 2x725 and 2x 2200 and many others but i will say that the 2x 1000 and the 4 x 1700 is my favorite setup if you decide to get a 4 injector manifold.

I am on the Elite 2500 and i really like the haltech system but it all comes down to who is going to tune it.

 

given they aren't looking for power near the top of 8374 flow range, running the higher trim compressor would just hurt boost threshold.

 

it’s hardly laggy. Mine makes 1bar at around 3750 rpm depending on load. In my opinion the 8374 is the perfect street turbo.

I’ve never once wished it came on earlier.

 

The higher trim compressor I was referring to was the "84". Which would come on later than the 8374.

 

my bad, but is there much difference with 1mm? It’ll be like what? 200rpm slower?

 

response will depend on many factors but the reason why I replaced the 8374 is because it was too responsive and it was a constant fight with the steering at the track …I was seeing 30psi at 3200rpm.. i was using a greddy t78 manifold (50mm runners) and 3.5 inch downpipe

its of my opinion also that 8374 is the perfect turbo for the street

 

I bought the car as a roller missing everything from the firewall forward, so I have a blank canvas ( part of the reason why Im struggling as well since I have nothing to go off of). The engine that I picked up came out of a single swapped car, but I dont know any details beyond that it was swapped, on stock ports, and the fuel upgrades.

 

I'm trying to achieve a fun street car that will have overhead, but not be really overbuilt to the point of needing things like W/I or a crazy V-mount. Like I said I would like to build something capable of making 400, but really only run in the mid to high 300's so that I know I'm not stressing the engine. Once this thing goes back in the car, I want it to never have to come back out lol.

 

controlling the heat is more important at that power level. Decent v mount setup with properly ducted radiator, and you’ll be ultra reliable.

change the oil a lot too 🤣

 

So after speaking with TurboSource, the recommendation for my power level and usage goals is the 8370, ID 1050s & 1750s, and Walbro 460. Considering my goals kinda but me towards the top of the 7670 and the bottom of the 8374, I feel like this is a good option.

It seems like the timing kit isnt as necessary as I thought so I'll be forgoing that. Still planning for the 1500, but want to know if anyone has experience with Haltech's flying lead harness. Currently dont have a harness and figure it would be better to just go aftermarket instead of getting an OEM one and having to hack it up. However I've heard a lot of people are having issues with Rywire harness, and I dont know a lot about the Wiring Specialties one either.

For the IGN-1As, are there any other off the shelf mounting options besides the cruise control replacement and the lower frame rail? Even if I dont use it, I'd like to keep the CC module in place, and the frame mount seems like it'd be a pain to do any work with. I know part of the reason for relocating is to get away from engine heat, but are the coils able to fit under the UIM or are they too large?

 

I’ve got a CCfab mount I’d sell. Alternatively advocult in the uk make a nice mounting kit.

 

I'm not aware of any other off-the-shelf solutions, but the IGN-1A's are fairly small, and if you're reasonably crafty you can probably come up with a good DIY solution for fitting them under the UIM. By using the mounting ear holes on the IGN-1A's, combined with some AL spacers, long M6 bolts & nuts, it's pretty easy to stack the 4x coils into a 4x1, a pair of 2x1's or a 2x2 configuration, then fab up some brackets to attach the block of coils to the engine, using one or more of the existing threaded holes on the keg.

If you go to a DBW throttle, you can chuck the CC unit and mount them in that space without losing the CC functionality, assuming the ECU you have in mind supports cruise with a DBW throttle, most do these days.

 

Good to know that they can still be put somewhat in the factory location. I could only find the CC and frame rail mounts so just wanted to check if anyone knew of others. I have no problem coming up with something, but if theres an OTS solution I like to go that direction. I like supporting businesses in our space especially when their product is higher quality than anything I can come up with lol.

No real plans to go DBW at least for a while. Just got a new throttle cable and my throttle body is in the middle of getting rebuilt, so I'm committed for a while lol

 

Race Only just came out with some new mounts.

Raceonly FD RX7 Block Mount IGN1A Bracket Kit - RACEONLY

 

Did another search and came across these https://www.mpfab.com/shop/p/mf5-rot...t-coil-bracket
Not sure how I missed them before as theyre the third search result lol

 

Those look like a nice mounting solution! For the custom wires you're going to need, I'd recommend MagnaCore USA - https://magnecorusa.com/

IMHO, they make the best custom spark plug wires in the market, I've had a custom set on my FC since 2017 and on my FD since 2020. They also make it pretty easy to correctly spec out your custom wire set order with them. For your IGN-1A's, just follow along with their directions for "DISTRIBUTORLESS TYPE SYSTEMS (COIL PACK/COILS)"

 

I just picked up the ARK IGN kit and Race Only sells one. Both are mounted under the UIM, in the general stock location.

 

Just put in the order for the full Raceonly ignition kit. Decided to just get everything from one place so I know it'll work together, and it'll be easier to troubleshoot if it doesn't.

With all that figured out, the last major thing I need is an engine harness. Considering that I bought the engine without the harness, I figure it makes the most sense just to get an aftermarket one. Nothings worse than having to deal with crusty 30 year old wiring lol. Since I'm planning to go with the Elite 1500, figured I'd just pick up the terminated harness from Haltech as well, but I'm open to other recommendations. I'm probably going to end up having someone else finish it anyway as my wiring skills end at plugging things together and basic soldering lol.

The only other harnesses I've heard people using are Wiring Specialties and Rywire, though I've heard the quality from both has really taken a nosedive since covid.

 

I would steer clear of Rywire, I've heard so many complaints and issues with them it's not even worth rolling the dice on.

I bought a wiring specialties harness for another project years ago, and it was well constructed, but I don't know if their quality has also diminished over the years.

I can't comment on the elite harness but I would think it still might need some customizations based on your specific setup, so expect to have to do a little surgery on it, as long as that doesn't scare you.

 

Having to add things don't really concern me, I just want to make sure that the base harness is sound, hence why I'm staying away from Rywire. I've heard too many stories of connectors being wired backwards and blowing things up.

 

Have you considered building your own harness? It's really not all that difficult, though it can be tedious work that demands lots of attention to detail, testing your harness & documenting it as you build it (to avoid problems later - ask me how I know ). All in, it cost me approximately $800 in materials (mil spec wire, connectors, terminals, heat shrink boots & tubing, etc) and about $150 in acceptable DIY-level tools (open & closed barrel crimping tools, quality wire strippers) to build a motorsports grade main ECU harness for my FD.

If you don't want to go that far, the "DIY-minus" option you might want to consider is buying a "flying lead" harness for your brand of ECU - these are basically harnesses that are only terminated at the ECU end with the appropriate ECU connectors, and have a fixed length of wire for all the engine connections that you terminate with all the appropriate connectors yourself.

 

Yeah the flying lead harness from Haltech was what I ment and what I'm leaning towards the most atm.

While it sounds interesting, building a harness from scratch is not something I really have the time or patience for. I also suffer from the "never satisfied with anything I make" problem, and while that's ok with brackets and paint work, it'll be a lot worse for something complex like a harness lol.

EDIT: What I'm looking at for reference https://www.haltech.com/product/ht-1...h-flying-lead/