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Quick update after the first start. I had a coolant leak after it got up to temp - the hose clip I used cut into the small rubber hose under the coolant tank. Fixed it with a new hose and a better clip. I then had some heat issues which I eventually figured out was an issue with one of the fans. A quick spray of contact cleaner fixed it, and both fans worked fine afterwards.
The only other issue is a small leak at the back of the sump. I realised after discussing it with Brett is that I tightened the bolts too quickly. I'm going to remove it today and only hand tighten the bolts, and then fully tighten them tomorrow after the silicone has set. That should hopefully seal it better🤞🏻
Wonderful job on this! I recently installed the Brettspeed manifold and turbo in a friends Rx8. Will concur that it's an pretty finnicky job to do but if I'm being honest, I thought it was easier to install than the GReddy manifold and turbo lol. The benefit was my friend has a spare Renesis on an engine stand, so we were able to fit everything up around the turbo and confirm clocking, etc all outside of the car first.
Wonderful job on this! I recently installed the Brettspeed manifold and turbo in a friends Rx8. Will concur that it's an pretty finnicky job to do but if I'm being honest, I thought it was easier to install than the GReddy manifold and turbo lol. The benefit was my friend has a spare Renesis on an engine stand, so we were able to fit everything up around the turbo and confirm clocking, etc all outside of the car first.
No, he just bought the manifold and engine mount. Luckily he's a welder by trade so fabbing his own downpipe and charge piping will be pretty straight forward for him.
No, he just bought the manifold and engine mount. Luckily he's a welder by trade so fabbing his own downpipe and charge piping will be pretty straight forward for him.
Surprised I never heard a dickybird ..... must have gone smoothly ?
Surprised I never heard a dickybird ..... must have gone smoothly ?
Oh you heard! I tagged you on Instagram with a little story video after we got it all installed last week (papaburgundy18 and popes_projects). Your instructions were clear and concise and everything was designed and fit to the mm! For him now it's just a matter of the piping and I think he'll be ready for youR tuning expertise!
Oh you heard! I tagged you on Instagram with a little story video after we got it all installed last week (papaburgundy18 and popes_projects). Your instructions were clear and concise and everything was designed and fit to the mm! For him now it's just a matter of the piping and I think he'll be ready for youR tuning expertise!
So you did (although I can't find it anymore). Thanks again for that.
For those of you wondering what I’ve been up to — no, I haven’t been having loads of fun boosting up and down the country. I missed a few key checks before fitting the turbo, and the gremlins all popped in to say hi! Long story short: I had boost leaks, a faulty ignition lead, some bad grounding points, and a dirty (possibly faulty) MAF. All of these issues caused the engine to bog down during the last test drive, and I’ve spent the past three weekends hunting down and eliminating all the problems.
Massive thank you to @Brettus for all your help! Lesson learned — and I’m now the proud owner of a new boost leak test kit. I've also learned how to properly read ME logs and diagnose potential issues. The car is back to stock for its MOT, which gives me a chance to give it a proper thrashing before putting the turbo back on. The fabricator was also on hand after the engine died and gave me some really valuable troubleshooting advice. Talk about great aftersales service!
To all future installers, make sure your electrics are fine, and do a boost leak test before the first drive!! I didn't bother to check my leads because the car always performed well.
Faulty ignition lead
Downpipe and CAT after the engine bogged down
Downpipe and CAT after fixing the MAF and leads
Repairing the pins on the MAF plug - top is before and bottom is after
Last edited by jacksback; Aug 6, 2025 at 08:14 AM.
Jack is back. Hoping to get started this weekend. I ordered a few more pipes and silicone hoses to redo the intake side, and I also bought some new bolts for the turbo, which I'm hoping will grip better.
I only got started yesterday due to issues at work, but made some good progress. I'm not sure what I did differently this time because the manifold slipped into place on the first attempt. I'm still surprised at how easy it was to put on, and I keep thinking I must have forgotten something before installing it
I also installed some new heatshielding around the massaged section of the firewall because the carpet felt very warm after the first long idle test. Today I'm going to finish off the pipe work, swap out the injectors, and do a boost leak test. I also have to install a replacement oil filler neck pipe after both my bolts snapped off.
Spent way too much time trying to remove the oil filler neck pipe, and eventually ended up drilling out the bolts. It isn't pretty, but it works. I also redid the intake and wheel well pipes, which removed about 6 clamps and made it a lot neater. The boost leak test was a success 🙌 Took it to 20 psi and only had to fix a small leak on the recirculation pipe.
Today I'm going to fill it with oil and coolant, tighten some bolts, flash Brett's tune, then start it up.
Quick update. I managed to test drive the car two weeks ago, and it felt really strong - but that only lasted about three minutes before smoke started appearing and the engine bogged down again. I went through the same checks I did last time to try and locate the final gremlin, but I still haven’t managed to get it to idle correctly.
Last night, I noticed something very strange and shared the logs with Brett, who suggested I swap out the primary yellow injectors - the same ones I had previously cleaned and flow tested with the four blues. That’s when it dawned on me. I swapped them the last time this happened, which is probably how I managed to get my fuel trims down and the car idling perfectly again, so that's the plan for this weekend.
Last edited by jacksback; Jan 6, 2026 at 02:02 PM.
Happy to report that the tuning process is almost complete. I used the EBC for the first time yesterday and finally hit 8 PSI. It was the first time I’ve ever been pushed back into my seat - what an incredible feeling in such an amazing car! Super happy that everything has finally come together! I only have a few issues left to sort out, and they’re all related to the exhaust and piping.
Huge thanks to @Brettus for the amazing manifold, pipe kit, tune, and all the support you’ve given me over the past year. Your info thread is absolutely key to building the RX-8 that Mazda should have released from the factory.
Congrats, it's a feeling you'll never forget nor get tired of!
Thank you. So true because I haven't stopped thinking about it. Can't wait to finish dialing in the EBC. There is about a 2 PSI drop at the top, so I'm going to set 9 PSI as my start boost.
Shopping list for future builders. Most of these items can be found on Aliexpress. I would suggest checking there first as the prices are more reasonable.
Do you have any additional photos of how your intercooler inlet/outlet piping is ran? I'm likely going to use the same intercooler, but with a top mount.
Do you have any additional photos of how your intercooler inlet/outlet piping is ran? I'm likely going to use the same intercooler, but with a top mount.
The greddy pic below should help. I used two 90 degree 3 inch to 2.5 inch silicone reducers on both sides to connect to 2.5 inch aluminium pipes running next to the oil coolers.
Last edited by jacksback; Dec 25, 2025 at 09:17 AM.
Our first nice Sunday of the year, so I gave the 8 a much needed clean. I also put heatshield around the battery cover and swapped out the blue conduit covers for black, which I think looks a lot better. Can't wait to tax it and drive it again 😩 Hopefully the nice weather is here to stay
No more flooding issues after replacing the primary injectors, even after a few strong pulls. Let the tuning begin!
