Yellow Bullet Forums banner

1501 - 1520 of 1577 Posts

·
Smoked another CTD
Joined
·
3,950 Posts
If you plan on using an EFR turbo. Make sure you budget in exhaust temp sensor and shaft speed sensor. It is very important you don’t over speed them or over heat them. If you do that fancy Gamma Ti turbine wheel will turn in to a bunch of pieces.

When I had a customer run them we learned fast. Have spare turbos. Data log the turbine inlet temp and shaft speed. Have safety measures set in your ECU to make sure they don’t over spin or get too hot.

The easier thing to do is just use a turbo with an Inconel turbine wheel.
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,502
A turbine failure on the first turbine in the loop could get ugly! That's an expensive day.
 

·
Registered
Joined
·
10 Posts
I built a setup on a 1.8L VW motor that used an eaton M62 supercharger being fed by a holset hx35 turbo. The 1.8 with the hx35 began to spool in the mid 4000rpms and would see full boost around 5000rpm. With the supercharger on there I was able to fully spool the same turbo by 2500rpm and have positive pressure between the two chargers by 1800rpm.
good read

my tuner VVT build just that, might have bin with a HX40 probably working at hi PR.

he had huge problems with slipping belts from the eaton.
this was worth mentioning in this discussion in my eyes
 

·
Registered
Joined
·
229 Posts
I would be surprised if he didn't do what I did. I ended up putting the alternator where the power steering pump goes and making the mounting bracket adjustable so I really up the tension on the belt. I never had an issue with slipping.
 

·
Registered
Joined
·
6 Posts
How would a compressor map for a positive displacement supercharger (M90 either Gen 3 or Gen 5) factor into twincharging?

I am making an effort to buy a W-body GM car, likely a Grand Prix GTP/GT ('97-07) or Buick Regal GS ('97-00) and it appears using a 70mm or larger turbo is the way to go. Since all the cars don't meet NHRA rule about cars with side air bags (2008 and newer), it will stay at 11.5 ET until I figure out I want to put a roll bar in it.

I am well aware of the shortcomings of the stock transmission. I am looking at solutions from beefed up 4T65e or a beefed up 4T80e; I would need to do less to the 4T80. I think I can save from doing some heavy duty parts by just controlling boost better. Most people opt for a fish tank or maybe the AEM True Boost controller/gauge to control the turbo either in a TC or Turbo only. It's worth spending either for a good controller like the Plex or AMS to help with traction and prevent torque spikes.

Besides the transmission stuff, am I on the right track with turbo sizing? I was looking at the Borg Warner S369.
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,508 (Edited)
I'm thinking that would pretty much stink.
What is new with your combo? Testing again any time soon? How is the track and was it a good season?
Nothing is really changing with the setup except I'm going back to a steel rod, and to a stronger piston. I did also pick up a billet crank, which is a departure from the stock crank, but that has never been a problem. It may be a while before I can divert enough time and money to the car to get it done, but I would hate to miss the DSM Shootout in August. I haven't missed one since I started going in 2002. The car will continue to be stuck at 7.90 though until I deal with the gearing vs converter issue that I suspect has been holding it back for a long time.

Forced Performance has expanded their FP400 line up to 88mm (and soon 91mm), using the BW 96mm turbine, and the GT50 turbine. I would at some point like to upgrade to one of those, keeping my 80mm compressor which is more than enough, but upping the turbine (currently GT45) to see its effect on overall back pressure.

The track is a longer story! But in short, we had a good season all things considered. We made some nice equipment upgrades, made a big improvement in track prep, sorted out a lot of the inherited bugs, brought back bracket racing here, and had some big no prep events (and others). On one hand, it wasn't rocket science, just a lot of time and hard work. On the other hand, it was a miracle that it all went so well. :D Projections for this year show solid growth, and with any luck we'll be on track to making some major updates to the place at the end of the year.
 

·
Registered
Joined
·
94 Posts
If you plan on using an EFR turbo. Make sure you budget in exhaust temp sensor and shaft speed sensor. It is very important you don’t over speed them or over heat them. If you do that fancy Gamma Ti turbine wheel will turn in to a bunch of pieces.

When I had a customer run them we learned fast. Have spare turbos. Data log the turbine inlet temp and shaft speed. Have safety measures set in your ECU to make sure they don’t over spin or get too hot.

The easier thing to do is just use a turbo with an Inconel turbine wheel.
Luckily i'll have both on my setup. My LP turbo is an 8374 and i've heard several people say not to push much past 100k even though the max on the compressor map is 128k. Guess we'll just see where it ends up. Was hoping to make 800+ on this setup but it seems that may be a bit of a stretch if i'm keeping the shaft speed down.
 

·
Registered
Joined
·
4 Posts
Hi Kevin, with your compound experience what can you tell us regarding EGT's I asume they would be higher on the hp turbo manifold compare to a single turbo setup
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,512
I don't have EGT data on my car, just individual O2s. But I would not expect appreciably higher EGTs on a compound turbo setup vs a single turbo doing the same thing otherwise.
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,514
In my case that is calculated automatically by the AEM 4 Channel WB controller. It uses a 0-100psig sensor.
 

·
Registered
Joined
·
94 Posts
well that definitely makes things easier. Do you see any considerable change in reported afr downstream of the recirc gate?
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,516
I do. All of my gates leak some actuation air down the valve stem, so on a recirced gate, it will make the AFR read leaner. My downstream O2 reads about 0.5 gas scale AFR leaner than the average of the 4 pre-turbo O2 sensors. I've thought about operating the WGs with exhaust pressure rather than boost pressure (which I often do on small turbo stuff), but there's some risk of plugging up the WG's valve stem/guide with combustion shit or overheating the diaphragm. CO2 would probably work better but I'm not looking to go there yet. In the meantime I trust the pre-turbo O2s and only use the downstream gauge for a visual going down the track.
 

·
Registered
Joined
·
6 Posts
I do. All of my gates leak some actuation air down the valve stem, so on a recirced gate, it will make the AFR read leaner. My downstream O2 reads about 0.5 gas scale AFR leaner than the average of the 4 pre-turbo O2 sensors. I've thought about operating the WGs with exhaust pressure rather than boost pressure (which I often do on small turbo stuff), but there's some risk of plugging up the WG's valve stem/guide with combustion shit or overheating the diaphragm. CO2 would probably work better but I'm not looking to go there yet. In the meantime I trust the pre-turbo O2s and only use the downstream gauge for a visual going down the track.
When you say small stuff, do you mean the tiny turbos that factories tend to put on modern turbocharged cars? I am thinking all the Borg Warner K03 stuff even the smallish Mitsubishi turbo on the Neon SRT-4.

I thought an interesting project would be to stick an EWG on the exhaust between the head and the turbine housing

61599


Boost control isn't really an issue but it won't hold more boost at high rpm without a stronger spring but I think back pressure is the real problem. Of course this can be logged. I don't have my Focus ST anymore, but I will get another one as finances permit.

I'm over fooling around with small turbos on these cars but I am curious just how much I could get out of the tiny BW K03
 

·
Registered
Joined
·
1,575 Posts
Discussion Starter #1,518
My main example there is when I was running 10.31 at 132 on a stock EVO3 16g turbo, 48mm or so. I had good results ignoring boost and controlling back pressure instead. To bring it back to this topic, this method would avoid putting air down the exhaust stream which then messes with the O2 sensor, since all of the oxygen is already spent.

I suspect you're right on the back pressure issue. Once you have to jump through to many hoops to hold boost, it's probably too high already. No amount of wastegating will help either, you need that back pressure do do what you're asking of the compressor wheel, on that particular combo. No free lunch there. Run the compressor to 98% of its capacity and deal with the exhaust side the best you can. Cam timing adjustments become a big deal at this point, I picked up 4 tenths ET in an afternoon of playing with cam gears on my car with that 16g.

Compressor limited tuning forces you to look everywhere for ET, and was one of the most helpful things I ever did on my own car. I'm sure I've told the story in this thread before, but the 16g is what made my car fast. I was stuck in the high 8s for years on a single turbo and on my first compound setup. When that flux core booger welded mild steel prototype first compound setup was pretty worn out at the end of its third season and I retired it in favor of the 16g, that curse was finally broken. The 16g went 10.31 as mentioned, a record at the time for DSMs and EVOs (down to 10.0 now). I put an old cast wheel 35R on it and the second pass went 8.89, a record for that combo at the time. A PTE 6766 went 8.23 or 8.26. And a 72mm Forced Performance Super 99 in a T3 hotside went 7.90s. Now I've been stuck there for 7 years and should probably try the 16g again, lol. In short, if you want to piss your life away dicking around with small turbos, I'm all for it.
 

·
Registered
Joined
·
6 Posts
Actually I don't, I put GTX3071 on mine. I wouldn't spend too much time on it, just to see if I can get 340-350 whp out of the stock turbo, enough to run 11's without a monster 60 ft time.
 
1501 - 1520 of 1577 Posts
Top