March 17, 2025, 03:43:38 AM

Author Topic: SRX7 - 1981 RX7 with SR20DET Swap  (Read 11760 times)

Offline FC3S Murray

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #15 on: February 24, 2017, 04:53:44 PM »
Outstanding job so far. Love the clean look of your FB, the SR compliments that engine bay nicely. Can't wait to see the finished product.


What are your expectations on power output?



13 years of abuse and still running STRONG!

SRM Performance Tuning LLC
https://www.instagram.com/fc3s_murray/?hl=en

Offline sommmatt

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #16 on: February 25, 2017, 11:19:02 AM »
Outstanding job so far. Love the clean look of your FB, the SR compliments that engine bay nicely. Can't wait to see the finished product.


What are your expectations on power output?

Thanks! I'm just going to run the engine stock for now and see how I like it, so it's just around 200HP at the crank, basically double what the car had before. It is by no means extreme, but past experience says I am extremely irresponsible with horsepower.


Is that why you're keeping the stock rubber mounts?  I am really looking forward to see how the suspension geometry works out.  I did my own coilover conversion on the front, and am currently looking at putting shorter shocks on so I will have more travel.

Yep. Beyond using the Nismo mounts which use the same dimensions, basically all the aftermarket stuff ends up being a solid mount because they use one bolt that travels through the entire mount.

Offline sommmatt

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #17 on: February 25, 2017, 11:28:50 AM »
Also thanks for all the support so far, the build still has a long way to go but I'll be chipping away at it slowly.

I haven't figured out anything for a fuel pump situation yet, looking at lots of different drop in pump solutions that are 1 billion dollars. The GSL SE tank and pump setup is apparently not the best either, I was hoping to be able to just bolt that tank in and go.

As well I haven't found a rear end yet, nor can I find a source on Moser axles to convert my rear end to the long GSL SE axles/bolt pattern/brakes. Moser seems unwilling to help in this regard. I've tried to a couple different rear ends or GSL SE complete cars that are trashed with no luck.

Offline digitalsolo

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #18 on: February 25, 2017, 12:03:29 PM »
Could you use an 8.8?
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.

Offline freeskier7791

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #19 on: February 25, 2017, 08:00:53 PM »
Ford 8.8 or 9 inch works.  I customized the stock sending unit to use a walbro 255 and it has worked fine.  You could also use a gslse tank and then run a different pump, or use an external high pressure pump

Sent from my SM-G920V using Tapatalk

https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline sommmatt

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #20 on: February 26, 2017, 12:45:45 PM »
Could you use an 8.8?

Yes but I would want a bolt in solution, and I really don't feel like dishing out the money (and time) for a Granny's bolt in unit at this time. Maybe down the road, or if I find one used I would jump on it. I don't think I'll break a stock axle any time soon, so upgrading now is just losing horsepower and adding weight.

Ford 8.8 or 9 inch works.  I customized the stock sending unit to use a walbro 255 and it has worked fine.  You could also use a gslse tank and then run a different pump, or use an external high pressure pump

Sent from my SM-G920V using Tapatalk



9 inch would be such a giant horsepower suck on a 2.0 engine. Works fine for the guys with torque.

I had read that the GSL SE tank has such a pitiful slosh cup that there's almost no point in using one of those tanks with an external pump. There are plenty of good in tank pump solutions through aeromotive or holley that I'm looking at but I don't feel like spending the money just yet when I have so much to do up front still.

http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=84/mode=prod/prd84.htm

This is by far the cheapest drop in pump solution but the slosh cup seems questionable compared to the high dollar stuff.


I also crammed my intercooler in place last night and cut a few holes, mocked up the ECU location and started opening up the wiring harness.






Offline txgs

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #21 on: February 26, 2017, 01:38:49 PM »
Great thread, thanks for sharing. I like the clean aspect of your car as well. Thanks for sharing all the pictures. I have been looking for options for my FB. I would love to hear the breakdown of suspension to replicate what you have accomplished so far but using my L33 5.3L
« Last Edit: February 26, 2017, 02:13:09 PM by txgs »

Offline FC3S Murray

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #22 on: February 26, 2017, 03:07:37 PM »
Man I really think since you have the car under the knife right now you should really take advantage of slapping some power adding components on that engine. They have got to have hybrid turbos and upgraded ecms for the SR20 don't they? Not trying to tell you how to build your car but man it would be advantageous at this point in the build.




13 years of abuse and still running STRONG!

SRM Performance Tuning LLC
https://www.instagram.com/fc3s_murray/?hl=en

Offline sommmatt

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #23 on: February 26, 2017, 07:03:31 PM »
Man I really think since you have the car under the knife right now you should really take advantage of slapping some power adding components on that engine. They have got to have hybrid turbos and upgraded ecms for the SR20 don't they? Not trying to tell you how to build your car but man it would be advantageous at this point in the build.

They definitely do but it's a down the road thing. I'm an auto tech by trade so swapping turbos or injectors or whatnot isn't really intimidating or even time consuming. The turbo I plan on upgrading to later is stock frame so it should install in an hour or so.

I plan on using an aftermarket ECM but later on down the road. At this point I don't know if this engine even makes compression, or if it will knock, or if any of the parts on it are bad. Throwing an aftermarket ECM into the mix before I've ever had it running is a good recipe for chasing your own tail. With the Nissan computer it should be running, reliable and normal, so I can sort out any of the faults with the harness or parts or fuel setup without having to question my ability to manipulate the tune or set up the ECM.

Basically, the day I get the engine to fire up, if all is good, is the day I want to mash the throttle.

Great thread, thanks for sharing. I like the clean aspect of your car as well. Thanks for sharing all the pictures. I have been looking for options for my FB. I would love to hear the breakdown of suspension to replicate what you have accomplished so far but using my L33 5.3L

Sure thing, but keep in mind I haven't driven this yet, haven't aligned it yet, or any of that fun stuff.

1989-1998 Nissan 240SX Subframe and Rack and Pinion Assembly
1989-1994 Nissan 240SX Lower Control Arms
1989-1994 Nissan 240SX Inner + Outer Tie Rod Ends
1989-1994 Nissan 240SX Front Spindles
1989-1998 Nissan 240SX Front Hubs (will come in either 4x114.3 or 5.114.3)
1989-1994 Nissan 240SX BC Racing Front Coilovers with FC RX7 Upper strut plates. (these were built for me this way by BC, I also managed to use TechnoToyTuning RX7 FB camber plates attached to Megan Racing front coilovers as mockup stuff).
1979-1985 Mazda RX7 TechnoToyTuning front tension rods
1989-1994 Nissan 240SX Front brake pads, rotors, calipers, flex hoses, can also for 5 lug use Z32 calipers or 5 lug S14 calipers
You will have to fabricate a steering column and steering shaft. I haven't finished mine yet so I haven't posted pictures, make sure to build a collapsible section.
The U joint needed to attach to the 240sx rack will be 11/16 in. 36-Spline. The one I used is Borgeson Universal 015225. Summit number is BRG-015225 and this is the link. https://www.summitracing.com/int/parts/brg-015225/overview/ Information bolded in case someone else ever has to search for it, I found this information in the dredges of the internet on a Starion/Conquest forum and still wasn't sure, but I guarantee you this matches up to the steering rack. It was fun researching all this stuff before I started buying parts.

Sway bar TBD. FB Rx7 sway bar will work if you narrow it by about an inch or two on each side, will bolt to the S13 control arms if you flip it upside down but it will rub on the coilover. S13 sway bar looks like it will work if you build mounting points on the FB frame.

Holes in the subframe need to be elongated. Shock tower holes need to be elongated. Lower control arm tension rod mount points need to be elongated.

And I still don't know if I can make the wheel sit in the center of the wheel opening without having ruined my caster angle.

Offline freeskier7791

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #24 on: February 27, 2017, 01:16:01 PM »
That pump solution is pretty weak for 200 bucks.  I haven't had issues with my pump and I have run an auto X with it.  I definitely need a better solution though 
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline sommmatt

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #25 on: February 28, 2017, 12:34:32 AM »
Nothing crazy today, just stripped out the engine harness that came with my engine.



Removed all of the provisions for the ABS, power steering, A/C (if I ever put that in, I plan on having the stock wiring turn the compressor on), Silvia body side connections and figured out where I have to feed this harness the constant and switched power feeds. Also marked off the fuel pump relay control, speedo output, tach output and coolant temp output. Now I should be able to throw it back on the engine and start shaping it.

If you were wondering, the coils and injectors are on sub-harnesses, which is why this main engine harness looks so small.

Offline freeskier7791

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #26 on: February 28, 2017, 10:58:15 AM »
nice progress, are you planning on re wrapping the wires?
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline ChuckLee

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #27 on: February 28, 2017, 09:40:03 PM »
Looks like you made quick work of that harness simplification. Well done.

Offline N2v8fcs

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #28 on: March 01, 2017, 04:25:16 PM »
Nice work!
:drive:
new personal best 11.45 @ 120 mph N/A car...9.11 @152 mph for the turbo car.


1987 FC  355 SBC, T-5, T2 rear        retired 5-4-11
1991 FC  383 SBC, sold to Dad. Now 5.3 w 76mm turbo, G-force T-5, 8.8 Ronin rear 
1990 FC  370 CID 6.0 w 88mm turbo, Powerglide, Ronin 8.8 w 3.15 gears

Offline FC3S Murray

Re: SRX7 - 1981 RX7 with SR20DET Swap
« Reply #29 on: April 19, 2018, 11:22:57 PM »
Updates!!!!!!!!!



13 years of abuse and still running STRONG!

SRM Performance Tuning LLC
https://www.instagram.com/fc3s_murray/?hl=en