We had five different single turbo FD's on the same dyno, same day, same tuner (Steve Kan) last weekend here in Florida. Besides my GT4082, there was an Apexi RX6, 60-1, T04e and GT40R. I would have liked a few more turbos in the mix but the results are interesting none the less. The GT40R's results were less than spectacular, not due to the turbo, but to a substandard engine with low compression.



The 40R did produce boost sooner than the 4082 and I'm sure it would have continued that way had the engine been healthy. My own engine, while not injured, is less than perfect. Apparently the mixture of Atkins apex seals with their smaller corner seals, and used rotor housings in good condition are not a good mix. It allows for compression blowby in a nutshell, something that's audible to those in the know such as Rolo and Jesus Padilla who were in attendance (and Steve too). Undoubtedly, I'd produce stronger numbers with better spool with a fresh, well built engine and new housings. My exhaust manifold primaries are quite large as well, larger than the current GReddy T78 manifold. Smaller primaries will waste less energy through expansion and help with spool as well. There's always something, right? Split was kept at 14 degrees. There's probably another 10hp messing around with split. One thing to note is the dramatic increase in midrange torque. I compared a dyno run I did a while back where I tuned with Steve's session. At one point I'm making about 60hp more in the midrange. Crazy. Car is much faster than before and a beast between 4 and 8K. Notice my power doesn't fall off past 7K like everyone else. This is due to the lower intake manifold being ported. I only did about the last 5" and it took me an hour to do. A good mod.



I've labeled each turbo next to it's peak hp reading number at the top. Steve tunes for 11:1 a/f ratio.



It's no wonder people say the RX6 is a great street turbo. I don't start to surpass it until after 4K rpm. All turbo numbers are within 2psi. I believe the 60-1 maxed out at 14psi while everyone else was around 16. No dyno graph for the T04e as I left before I could get a printout of that tuning session. I believe it maxed out at 330rwhp due to boost controller issues.



Anyway, enjoy and observations welcome.

I'm going to make that dyno graph a bit bigger for everyone...

Here's the difference between me tuning my own car and Steve tuning it. Although I did not spend any time on my midrange like Steve did, I'm sure he would kick my butt regardless. They're on different dynos but I believe the numbers are relevant. Each are the uncorrected numbers. I now believe the Clayton is reading high, which makes my results even more impressive.



RPM Me Steve Difference

3K 80 72 -8

3.5K 117 109 -8

4K 174 160 -12

4.5K 215 240 +25

5K 230 280 +50

5.5K 280 322 +42

6K 309 365 +56

6.5K 340 379 +39

7K 380 390 +10

7.5K 391 390 -1

8K 401 394 -7



Different dynos, different days. Definitely hotter when Steve was tuning. I plan on hitting the Clayton again soon to see how much of a difference there is. I have a feeling there's about a 8-10hp difference between the two which would negate any of the lower readings from Steve's tuning.

Here's the GT40R vs. the 4082. One question I do have is whether the 40R is the larger 88mm wheel? Looking at the inducers, the two turbos look identical with the compressor covers on. Naturally, Russ' numbers with the 40R would be MUCH better with a healthy engine.

My best run, uncorrected numbers.

That's pretty dissapointing on the GT40R. How bad was his compression?

You'rs is verry impressive! ...only 200rpm's later then the BB 40R.

Nobody had the new R85?

michel my rx6 was running 14psi and i hit better numbers than that actually. i got 351.8whp and i believe it was about 299.6 torque. not suure on the torque number but it was above 296 and below 300. i am sure about the whp number though because harrison wont shutup about him beating my car by one horsepower! steve said i would have been able to hit about 370 whp but i was having some injector breakup and i didnt want to push my luck anymore that day.

LOL, we'll have to put the smackdown on Harrison https://www.nopistons.com/forums/pub...#>/biggrin.png



I believe your higher numbers were the uncorrected numbers. It's strange as it was fairly hot that day. If anything, I'd think the corrected numbers would be higher, not lower.

I don't want to say too much about the 40R until we find out why it was loosing compression. It was pretty bad though. Enough that it would make a huge difference in the final dyno numbers.

Michel, I think it sucks for you to have done all that work only to get shot down by some old housings and some corner seals. Thanks for sharing your dyno sheets. I only get more excited for a r85 with each post.

Sorry if this has already been answered.



What fuel (octane) where you guys running during these runs?

Thanks for posting up those results, always interesting. Ya know I think I have the record for torque with the rx6. I made 385rwhp with 352rwtq @16psi. Too bad I never dynoed my 62-1.

Pump gas for everyone. Yeah the corner seal situation sucks, but the car is still damn fast, enough to get me in serious trouble :-) My plates should be just fine so I may have Steve Kan rebuild me a motor with new rotors/housings using the newer Mazda 2mm seals. He can check my porting while he's at it https://www.nopistons.com/forums/pub...IR#>/bigok.gif



I also think there are things I could do to further enhance the setup I have now. The GT4088 was just an experiment. A good turbo but there may be a better matched turbo to my application. Live and learn, right? I'll be anxious to see your dyno numbers with the R85.



Honestly, all of the cars could have made more power by jumping to 11.8:1 and messing with split and timing a bit more, but what we all have are nice safe powerbands that will allow us to slaughter Supras with twice the hp and most cars on the road. https://www.nopistons.com/forums/pub...1047683473.gif



Steve definitely did a great job. It was worth the price just to watch him tune all those cars!

haha you can really see how much i need a boost controller... everyone had hit full boost and i'm just chillen at 12 psi as my wastegate started to slowly creep...... i want another 70 hp in the midrande damnit........

what rx6 did you have? i have a rx6a.

I guess it was the original rx6. That was about 3 years ago.

I have a feeling Harrison, that if you had a boost controller, you'd be above me until 4K rpm, similar to John's RX6 curve, but slightly less. And you'd carry more top end with the bigger hot side.

Michel

yea i have an original rx6 also. mine is about 3 years old. i did make 366 torque on one run but...i also almost blew my motor. so if you want to say that i beat your torque number then okay, and if you want to say that doesnt count cause it was a mistake then okay lol. what kind of porting did you have on your motor also? i am on the stock ports

I had a good sized street port done by rotorsports.

94touring you were one of the reasons i went with a rx6 back when i was choosing a single 2 years ago. i thought to myself how great it would be if my car had numbers like yours!

https://www.nopistons.com/forums/pub...O_DIR#>/11.gif Front Rotor 6.5, 6.6, 6.5 Kg/cm

Rear Rotor 4.6, 5.1, 5.2 Kg/cm

https://www.nopistons.com/forums/pub...IR#>/bigok.gif Thats cool man, I like hearing things like that! I had a lot of fun with that turbo.

oh man russ that sucks...... is the shop gonna do a rebuild for free as its almost brand new anyway?



oh and john, 94 touring made his number at 16 psi.... not at 25 LOL....



i want a gt40r kit.... though i'm not willing to pay 1700 dollars for a dp and manifold as the turbo and wastegate can be had for just about 2000.



harrison

Car is going back to the shop next week. We'll see........

Thanks for the write up and sheets, Michel et all.



Steve can work some magic. Only a couple of tuners I trust out there...Steve K. and Dimitrious K.

can u take out the TQ figure in the first pic and post again?

Im impressed with the RX6. It looks like it gives good usable power pretty early.

Can you give some more detail on your seal problems? Your running Atkins 2 piece seals and their "smaller" corner seals? What do you mean by their smaller ones. I have atkins 2 piece seals with their solid corner seals right now in my engine. Haven't got it in the car yet though. Thanks.



-Marc

I think he meant the corner piece of the apex seal instead of the corner seal. He was reusing the rotor housings which could cause compression leak switching from OEM to atkins.

Why would it result in lost compression? There still 2mm seals. Something to do with heat expansion, or...? Im curious since I have two good condition USED rotor housings in my engine with atkins seals.



-Marc

I don't fully understand it myself. I merely passed on what was said to me by several people very experienced with rotary engines. Essentially the grooves in the rotor housings, caused by the stock Mazda seals do not line up with the Atkins 2mm seals. As the Atkins are not identical to the Mazda seals in OD dimensions, using them with used housings do not provide the best of seals. Running under boost conditions tends to "stabilize" things but it's something that can apparently be heard while holding the throttle steady in vacuum at say 3K rpm. Rolo noticed it when Steve was tuning for driveability on the dyno.



My used housings were in excellent shape when we pulled the motor apart (JDM 2 rotor Cosmo). I know many of the best rotary engine guys refuse to reuse housings.

Michel

Can't take out the torque figures as I do not have access to the dyno's computer. I only have the printouts. I can send you a high res scan of the dyno sheet if you'd like. Just PM me with your e-mail.



Sorry for the late replies. Been busy w/ work and the server didn't notify me via e-mail there were new posts!

Thanks for the reply. Well, looks like I'll just have to see if mine does the same thing. Though I'm pretty sure, Dragon and JspecRacer7, among others are usings Atkins seals with used housings. *Fingers crossed* https://www.nopistons.com/forums/pub...IR#>/smile.png



-Marc