lol!
I like your elegant solution to the hose issues. I'm not sure if that attachment is retrofittable to the actuator I already have but I will check with Tial.

 

Hmmmmm….that doesn't seem right. When I had my Champion 68s on pumpgas (not far off from ACN91) I could get 60-100 of 3.0s on flat road. Started around 3k rpm in 3rd and floored it. With a 3.8L built engine you should be able to turn up the boost at ANY rpm so I'd expect your times to be at least as good as mine were!

 

Thanks for the feedback. I hope that anyone considering the move away from vtgs will find it less intimidating after learning from my experience.

 

It is retrofittable as the threaded portion is the same on both the barb and -4AN fitting. My actuators originally had the standard barb fittings but I swapped them to -4AN prior to install. Tial can send you the fittings if you contact them but swapping the lines with the engine in the car may be a bit of a knuckle scraper. Lowering the engine a few inches will definitely help. When the engine is out of the car it's a breeze of course.

 

I have definitely thought that my car should be posting a bit better numbers than it does. My best 60-130 pull is 7.5 seconds- that's in 4th gear only. I'm a bit slower in the run with 1 shift (3d to 4th) because the boost falls off when shifting, etc. That all being said, my car has a custom EVOMS tune, and I've data logged pretty extensively. I'm running 22 lbs of boost (sometime transiently it''ll hit 23 pounds). With 91 octane, it was a pulling up to 6 degrees of timing. Now with 2 gallons of E98 mixed with 91 pump, it is not pulling any timing. So I'm pretty confident that the car is running well. Fuels trims, etc, are good, although I'm nearing maxing out my injectors, which are the stock Bosch 997tt injectors. So I'm not quite sure what to think..... lots of people post these crazy fast numbers compared to mine. Maybe it's the driver..??! That being said, I've been around cars for quite a few years and have extensively driven 930's, old 911's, C6 Z06's, GT500's, etc....and the pulls we are talking about aren't too dependent on driver variation.

BUT- all that said, my car is faster than the new c7 Z06 which is the same weight and has 650 hp and 650 tq. So when looked at from that perspective, I think I'm probably running about where I should and my car is making 650-700 hp. EVOMS is currently making me a custom E30 tune- I haven't gotten around to installing it and testing yet. It may wake the car up a bit.

I love the idea of just sticking to 91 pump and making the numbers that you are. Very tempting to go your non VTG route. Again, thank you for this discussion and contributing to all of our knowledge.

 

For comparison, I used to have Protomotive 63vtgs and Proto tune. In 4th gear only I could do 7.2s 60-130 so I would expect on a built motor with 3.8L that you should be able to get a better time, and with 68s too. I was able to get 6.9s with 68s in 4th only. Something doesn't add up...unless you are in a hot climate for the runs?

 

All of my runs were done at 60-62 degrees F, 330 feet above sea level at 0 decline. I'm here in central California. I'd be much happier if I was doing high 6's or very low 7's in 4th only. When I look at my vbox graphs, if the car were a PDK (or tiptronic) with no boost loss between shifts and a nearly instant 3-4 shift, I would be at 7.1 seconds. But yeah, 4th gear only I'm at 7.5. If I went out and found a 3% decline on a cold winter morning below freezing, I suspect I could probably turn out a 7 second time- or heck, maybe even a high 6......maybe. Were your runs on a flat surface, and what were your ambient temps and altitude?

I'm not sure what else I can do at this point. My data logs look good according to EVOMS. It seems that any more boost or ignition advance isn't much of an option at this point.

The motor was fully rebuilt 2500 miles ago by a reputable shop in the Los Angeles area and tuning was done by EVOMS. One question I have for you- were you on stock injectors when you were running 68mm VTG's?

Many thanks for your input- this is really helpful.

 

Was it House automotive that built your engine? My understanding is that a 3.8L engine will have more low end tq and better flow so there's no reason I can see for your performance numbers. I am in Canada and the roads for pbox runs are reasonably flat. Certainly less than the 3% limit. In 60s and a 4th gear run starting at 50mph I could get repeatable 60 to 130 of 7seconds with my 68s. Your engine build must have cost a pretty penny, i would have put in a boost controller at the same time and gone aftermarket as it would have just been an incremental cost increase. The engine would have to come down again now to retrofit a boost controller.
I cannot believe you are on stock injectors with your build!! The 68s definitely need more flow even on pumpgas. If you are hitting 22 psi you would probably have injector duty cycle over 90% which would show in a datalog. If u have access to e85 I would recommend u change injectors and tune and run e85. If u want to stay on 91 i would recommend bigger injectors and my Xonas as u could turn up the boost in the 4k rpm range without worrying about the rods and your car will fly.

 

The shop that rebuilt the motor was GMG in Santa Ana. Indeed it was pricey. It was rebuilt due to a broken timing change which trashed the motor. At the time, I was pretty upset about dumping yet more money into the car, as I had recently bought it and paid at or above market value, assuming it was going to be reliable long term. I went ahead and had them do a 3.8 conversion, Carrillo’s, studs, gt3 oil pump, etc.

At the time, I was not interested in running e85 due to my perception that I’d need to be checking ethanol percentage with each tank, worried about water absorption, etc, etc. I talked to EVOMS and was told that the stock injectors were adequate for 91 octane, and would support 700+ crank HP. With 91, I’d be at the high end of the duty cycle, but the injectors themselves wouldn’t limit the power- the 91 octane and associated knock would limit the motor before the injectors would. Research on my end confirmed that the stock injectors were good for 700-750 crank HP. I was pretty happy with that and stuck with the stock injectors. But in retrospect, I wish I had gone with ID 1300’s or Siemens injectors. I may end up doing that at some point.

Ill see see if the injectors will keep up with the new EVOMS E30 tune, which hopefully I’ll be testing in the next week or so. EVOMS said the new tune will up the boost in the midrange.... I’ll see how that affects the times.

Thank you you again for your very helpful info. And I totally apologize for hijacking your thread! Please keep us all posted on your Xona progress!

 

Stupid spell correct- broken timing chain

 

No worries about threadjacking at all, post away.

That is an awesome build and one I wish I had. Hopefully I'm not forced into doing one, lol. Sucks what happened to you but at the end of the day you should have a bulletproof engine and now you should be rocking some seriously fast times. But you aren't yet...

Do you have stock or aftermarket turbo inlet pipes? what intercoolers and exhaust? I assume an aftermarket clutch?

 

Full GMG headers and exhaust, GMG World Challenge IC’s, do88 inlet pipes. Clutch is the heavier duty one that’s one step above the Sachs 2.5 (I forgot the nomenclature of it, it’s the one used in 4.0l GT3’s). My TB, y-pipe and intake plenum are stock.

I’ll keep working with EVOMS. I know the new tune optimized for a bit more ethanol that I’m going to be testing will run more mid range boost. Hoping it’ll help.

Thanks again for everything!

 

The manual is a challenge. I would have chosen other language and names to describe things. Can't you just run the car with the boost controller turned off and log max boost on the AP to find out what the wastegate spring only is doing? Shouldnt this be the 'baseline boost' or per HKS the 'Std. Max Boost'?

What was the cracking pressure of the spring they shipped with? I thought it was 1bar or 14.5psi which would be in that target 65% range.

^^^^NEVERMIND I went back and read the answers....

 

I'm surprised the rigid boost tubing was resued. I replaced all my hoses. The AN solution is nice.

My controller is mounted here. Nothing is really accessible. No filters inline, they are a weak link.

 

Hey Sean,
what is that "Vibrant" thing above the plenum? So the filters aren't necessary? Is the actuator screwed into the intake runner or is it just sitting on the surface? I assume equal length tubing to the wastegates even though the actuator is mounted on one side of the engine?