New pull tonight. Still not revving it out because I don't want to be going to fast while testing the limits of these new tires.

Re-calibrated the new tires and longer 3rd gear. You can see in third gear at ,6500 RPMs I am at 82 mph. (8200/6500)*82 mph = 103 mph (top of third). Should be closer to 105 mph based on Tremec calculator. I may need to recalibrate at a higher speed.

Also you can see that duty cycle on the turbo gradually increase with RPM so the power doesn't slam the drivetrain. I saw 20 psi last winter at 3900 RPMs, which I will try to stay away from.

Need to decease duty cycle in first gear to 0.

On this pull hitting 20 psi at 5,500 and 24.5 psi by 6,500 RPMs. Car definitely feels slower with the longer 3rd gear and limited boost from 4-5k. As cold as it was out tonight, I accelerated at 10 MPH/S, which is okay for the longer 3rd gear.

I will just keep adding/subtracting boost where I can to make it hook on these tires.

https://cimg9.ibsrv.net/gimg/www.rx8...f99201b066.jpg

Quick update - I have been running the car every week just to keep it from sitting to long. I have taken the car out the last few nights and noticed that my manifold was glowing after some easy cruising. By 3000 RPMs and cruising loads my total timing is in the low 30s. I tried all the way up to the high 30s and I still see the manifold glowing.

I ordered a new EGT sensor as my last one melted apart when the exhaust sleeved failed in my front rotor. So hopefully once I get that installed, I can verify that there is no abnormal temps. I also checked that all of the coils are functioning normally. The two leading plugs look fine. Car starts, runs, and drives normally. I may double check that I have the coils wired up properly. The only other thing is that I haven't been able to get E85 lately so I am running around at like 15-20 ethanol content, maybe the lack of ethanol is just making things burn a bit hotter. I haven't really changed my tune up that much for it to be a setting thing.

Plan now it to get some higher E content in the tank.
Refit a new EGT sensor in the front rotor.
Double check the coil wiring
Check the trailing spark plugs

Hell the glow maybe entirely normal as I generally would get 1500 F during cruising and mild steel should glow above 900 F, so I may just be chasing a problem that isn't really there.

What is your cruise AFR ? Makes a big difference to EGT !

I tuned my cruise afrs to get richer as loads increase ...which is easy to do with maf tuning. At high cruise speeds (say 70mph) or when cruising up a slight incline egts can go crazy if you don't run it rich.

My cruise AFRs tend to bounce around between 12.5-14:1, averaging somewhere in the mid 13's. Even after driving and letting the car idle, the manifold still glows just not as bright....

Sounds ok ...pays to actually log egt while cruiseing to see under what exact conditions the egts go high.

Added 4 gallons of ethanol and got her up to about 53%, still glowing. Double-checked all of the wiring to the coils and to the plugs and everything is 100% correct, still glowing..

I will wait for the new EGT sensor to see what that says,..

Mine have always been glowing and chased a issue that dont exist for too long. Its probably fine lol, i have 1 egt per runner and it gets up to 725celcius when highway cruising (3500rpm 5th gear, 13.5 afr) and glows for a while when i let it idle after highway drive

You may be right. It may just be that I am looking at the manifold when it is pitch black outside, in normal light you can't tell. Either way the new EGT sensor should be in today and I can verify that the EGTs are not abnormal. At least that way I won't feel guilty hammering on the engine.

When the EGT gauge was previously working, I never saw EGTs go over 1650 F (900C) and that was at WOT for good while.....

Allright. I got some numbers from the new sensor and it looks like I am okay.

Idle @1,800 RPMs, 13:1 AFR, 17 deg leading, 800F (425 C)

Cruising at 2,000 RPMs, 13.5:1 AFR, 23 deg leading, 1,350 F (730 C)

Cruising at 3,000 RPMs, 14:1 AFR, 35 deg leading, 1,450 F (790 C)

Cruising at 4,000 RPMs, 14:1 AFR, 37 deg leading, 1,550 F (840 F)

Manifold and rear of turbo still glowing. I could probably richen up cruise a bit to get things a tad cooler.

If I got back to idle after crusing for a few minutes the temp slowly creeps back to 800F....

Thougths??

FYI the EGT probe is 1.5 inches from the front peripheral port so it reads about the highest EGT the system has....

I have same turbo but.
 

I'm going to change .91 to .88 a / r turbing housing
I have Rx8 R3 6 speed transmission, differential 4.44 with 20” wheels. Spool 4,500rpm I don't like.
I want Spool at 4,000rpm or close.
I'm going to try .88a/r T4. Now only 12psi, 11.2afr. I need to change clutch and fix some details for dyno and boost. Soon we will see what this turbo does at 20psi with 91 pump gas.

https://cimg0.ibsrv.net/gimg/www.rx8...79855f6dc.jpeg

That will not make enough difference for you to notice it .....

Swapping housing that close apart probably wont make a difference.

The 6 speed gear ratios are very close, turbos need load to spool. Swapping to a 5 speed transmission would probably help you load up the power better....

I don't want to change it at the moment. But it could be in a future. We'll see what happens.

I'll try. I don't want to switch to a 5-speed transmission at the moment. maybe later, when it doesn't work anymore. we will see.

I hope
 

with the previous turbo the change from .96 to .84 it was very good. I would say almost perfect from 4,600 to 4,000rpm. I hope improving between 500 to 400rpm, it would be perfect. I hope🙌🏽.

Well yeah

0.96 - 0.84 = 0.12 delta A/R, that’s a noticeable change

but what you stated earlier is

0.91 - 0.88 = 0.03 delta A/R, or only 25% of the change above. Unless those numbers are a typo mistake, then like everyone already said; not going to be much change. A 500 rpm improvement on that size turbo seems doubtful all else being equal. :dunno:

ps: don’t you have a dedicated thread on this?

.

Isn't the 0.91 a twin scroll and the 0.88 a single scroll ? That will make spoolup worse if you have a genuine twin scroll manifold.

Didn’t think to check those options; yep.

I don't expect 600rpm but maybe 300 to 400rpm and it's good for a heavy car like rx8. Investing $ 80 and improving something is good.

yes 91. Twinscroll and .88 single. No twin scroll manifold. I would only spend $ 80. If it doesn't work, I change again to .91. Borgwarner says I don't need to modify the downpipe. 0.91 and .88 fall into the same position. I don't lose much just $ 80 I change it myself in the workshop. So we have more information about the things that work on the rx8
https://cimg6.ibsrv.net/gimg/www.rx8...ec478207f.jpeg

here on the island almost all the rx8 has 500 and 600hp. use sxe366 with .88, .91 or .96 does not matter which one. The 2tep load the turbo. All with 100oct sunoco gasoline. They only use it 2 or 3 sunday a month.I am one of the few who uses the rx8 daily without any problem. I am the only asshole that I look for 420 to 450 with 91 pump gas. With least lag possible. This was recently in the workshop with only 91 shell gas pump. 508hp old dyno
in a modern dyno they are like 540rwhp

Rx7 convertible 500hp dyno day 13b borgwarner

You should convert to twin scroll manifold rather than change housings .....that will do what you want it to . Housing change def. wont!

I was thinking the same thing. Looks like an easy conversion.

New pull this afternoon.
Still ramping the boost up slowly for the sake of the transmission.

62F Ambient Temps
20-24 psi
40% Ethanol Content
MAT 80-105 F
Leading Timing 19.7 down to 14.7
AFR 12:1
EGT never exceeded 1600 F

Delta Rate 863 or 11.5 MPH/S acceleration in 3rd gear. Only taking it up to 6700 likely skewed that result.

Car is definitely lazier up to 5500 RPMs with the reduced duty cycle.

Time to add some boost above 5500 RPMS in 3rd gear. Car is way faster in colder weather.

I really think a S366SXE 80mm turbine and 1.1 AR rear housing (with a full 3.5" exhaust) would be great for this car. The slower spool may lessen the torque below 5,000 RPMs, but would take this car to another level from 5,500-8,200 RPMs.....

https://cimg2.ibsrv.net/gimg/www.rx8...65bf866fc6.jpg

I like it; MOAR TURBOZ, lol

that would be good for low-mid 6XX HP range :shocking: