My 68s are hitting 19psi at 4082....mind you running ****ty Champion headers that have a leak somewhere and a catted exhaust. These xonas looks like they would perform better on the street with the E85?

 

No idea about e85 on these Xonas. I can hit over 20psi by 4k rpm if I let it, but I don't, lol. I loved my Champion 68s when I had them but they were pricey. The sweet spot was definitely the 63s as far as performance per dollar. The 63s, 68s and the Xonas are great "street" turbos because they spool quickly and pull hard. On pumpgas the Xonas rule the vtgs...by a large margin. I would say that the Xonas on pumpgas are equivalent to the vtgs on e85 and the pbox numbers agree...

 

numbers don't lie, that's for sure. good stuff

 

I have the same XR980 turbos Bogg has and they spool very fast. We have actually detuned the torque down low to make it more suitable for my use and have a peak of 718 ftlb wtq on a dynojet at 4500rpm with a 697whp peak at 7360rpm. This is on 91 octane at 17psi. These are fantastic turbos by all measure.

 

Pwdrhound-

Are your whp and wtq numbers on 91 octane with or without Methanol? Thanks in advance!

OP (Bogg)- great reading this thread. Very informative and interesting. Thank you.

 

No Methanol. This is on a 996 4.0L and I'm using Marston Aerospace 4" intercoolers. File is still very conservative even for 91 octane as we are still in the break in / set up phase on a new motor.

 

Hey Bogg...random question. What did you do with the signal lines that used to connect to your diverter valves on your vtg turbos?

 

I want your engine!

 

I believe they were removed completely...iirc, they plug into a harness somewhere and the whole thing was removed. That segues into something I was going to talk about related to some
difficulties I had:

My shop is very good and did a great job with the project. But I recently realized they made one little mistake...I'll back it up a little first. When I had the heavier spring in the wastegate I wasn't getting the desired control (part of it was setup related). Tial advised getting a kit together (they gave me a parts list) so I could test the wastegate for exact cracking pressure and range, which is something my shop and I should have done while the engine was down. But I'm a noob when it comes to aftermarket turbos and so was the shop. Anyway, I put together the pressure regulator and hosing and a compressor and when I tried to take the hose off the barb on the wastegate I just couldn't get it off. I figured "no biggie" I'll just cut the last 2 inches off and there should be enough slack to reattach it afterward. After I made the cut I peeled back the heatshield wrap and to my horror/surprise/dismay discovered that my shop had reused the vtg tubing. After the first 2 inches the tubing turns into a clear silicone skinny tube so there was no way to just reattach the whole thing back onto the wastegate barb based on the way I cut the tubing. But there was enough to fit on the barb and I used a small worm gear clamp, and this is just a temporary fix. At this point I realized that the diameter of the vtg tubing wasn't the "correct" size and I was a little surprised when Tial told me it probably didn't make a huge difference. After I changed to a softer wastegate spring the pressures that the tubing sees is lower (since the boost controller controls above 11psi based on the amount of preload I put on the spring) so it will be ok for now. I will check it regularly. We mounted the boost controller solenoid at the back of the engine near the back of the intake plenum so it isn't really accessible without dropping the engine which sucks considering I replaced everything when the engine was down. Although afterwards I realize that I didn't know anything about the RMS (rear main seal?) so maybe when the engine comes down I will get that checked/replaced. I think I would like to move the boost controller solenoid somewhere else too so that it may be accessible in the future. God forbid those stupid little expensive inline filters clog or something, lol.

If anyone else is going to get this set (or anything similar), make sure you check the actual wastegate pressures, and adjust if needed, BEFORE reinstalling the engine. Hell of a lot easier! I changed the springs using 2 jacks and it took more hours than I'd like to admit. It would be much easier on a lift but I didn't want to take it elsewhere for various reasons. The spring change is difficult in the 997tt application because the 2 stems (with an extension nut in between) are bent and not straight so it makes it much more difficult to unload the spring before opening the wastegate actuator canister. Tial sent me a video how to replace the spring when there is a straight stem and we modified the technique for the bent stems. Wasn't easy and my fingers were sore but got it done. Once again, setting it up properly before reinstalling the engine is KEY!

 

Wow- that's impressive! My motor is a forged 3.8L conversion with Mahle 3.8 p/c, carillo rods, EVOMS headstuds, and GMG Intercoolers. I'm running 68mm VTG's on 91 octane. I add 1.5- 2 gallons of E98 per tank to boost octane and help with the EGT's. I'm definitely no where near your power levels. I'm probable around 650-700 crank HP. My 60-100 times are 3.2 seconds in 3d gear. It's tempting to do what you or Boggs is doing and switching to non VTG. I certainly don't want to give up drivability but it sounds like your spool times aren't too bad. My car is a semi-daily driver. I'm assuming I would need to budget $10-15K (parts and labor) or so for the conversion if I had a shop do it.

 

My other option is E85.... That's crazy fast. Are you PDK, Tip, or 6 speed? Your numbers are awesome.

 

if you have access to E85 then I think a lot cheaper to tune for E85 on a built block with your current turbos.

 

I never liked the rubber wastegate hoses and the barb on the Tial IVM 2.5 housing makes removal nearly impossible without cutting the hose off.. In lieu of the OEM hoses, we installed braided -4AN hoses which bolt directly to the wastegate housing which makes for a bulletproof installation and easy removal. Tial supplied us with a -4AN male fitting (identical to what is used for the water lines) which threads into the housing in lieu of the barb fitting. This makes for a much more elegant and functionally more durable solution.

 

My shop can build one for you....

 

We are actually not going for all out power as that is not useable for my use anyway. The whole idea of the 4.0 engine is to be able to run lower boost and give the engine a more normally aspirated character similar to that of a GT3 engine. These XONA XR980s fit the bill as they spool almost instantly but you can still get them to come on relatively softly to achieve a GT3 type power curve. Our target is right at 1.25 to 1.3 bar boost (18-19 psi) which is giving us right over 700 whp with a very conservative 91 octane file and a 7500rpm redline. Our torque is detuned down low to give a peak at 4500 rpm and hp peak occurs at 7360 rpm. These turbos are very efficient on the top end and we still show almost 500 ft.lbs of wtq at 7500rpm.

I ran a smaller K16 framed custom turbocharger on my previous 3.8 and 3.6 Mezger and there is simply no comparison to the XR980 turbos. On the 3.8 the K16s put down 720 ft.lbs of wtq at 4200 but simply did not have the ability to flow past 6500 like the XR980s and were down almost 100hp on the top end.