Twin charging (again) - Page 7

chuntington101 · Oct 9, 2009, 10:30 AM

Quote:

Originally Posted by kjewer1

That last pic is Paul Volk's 2g DSM. Compound turbo with a 16g and 60-1. I'm running a similar setup on my talon with a 50 trim and a S475.

I considered the rear mount turbo concept at one point for a street car looking to go compound turbo without trying to stuff it under the hood. IMO, if you're going to run 2 turbos you might as well compound them and not have to deal with valving them in and out, etc. Only point that would require special consideration is the wastegate on the small turbo. You need a lot of it, and they all have to dump back into the main exhaust discharge. The long run from the back of the car to the front would actually be beneficial in a setup like this.

Kevin have you got anymore details on that setup? How about pics? What about dyno graphs? Be interesting to see how fast you spooled the rather large s475! How much power do you think you where putting down? Cheers chris.

kjewer1 · Oct 9, 2009, 01:02 PM

The S475 is a T6 1.32 turbine, so it's massive. Hard to say when it spools though. I dynoed it once at 40 psi but I start the test at 6500 so it doesn't show spool. At the track the 2 step effectively disables the primary turbo so no data there either. I'd estimate full boost (40-45 psi) in the 5500 rpm range though. How much power is a trick question thanks to the auto trans. Best thing to do is just go by trap speeds and weight (155 mph at 2440 lbs). Last dyno was 586 whp on a mustang dyno, but that's obviosuly misleading.

Here are the first two runs on the setup.

http://www.youtube.com/watch?v=vhiKLm9E6UA

Som pics here.

http://s116.photobucket.com/albums/o...r1/RWD%20pics/

chuntington101 · Oct 13, 2009, 02:22 AM

kevin thank you for the info and pics. Looks a killer setup. Got a few more q's though, sorry. What size waste gates are you using on each turbo? Also what advantage has the 50trim given you? Its just you will be launching with the s475 already spooled and the auto should keep it there. Also do you have any pics of the turbo kit off the car? Whats the exhaust manifold like? Cheers chris

kjewer1 · Oct 13, 2009, 07:50 AM

2 V44s on the small turbo and one on the big turbo. The 50 trim was chosen because it has the size ratio to the 475, is cheap, and will spool fine on a 2 liter. When I launch the 475 is making 0 boost, because of the 2 step mentioned above. I leave on about 28-30 psi from the 50 trim, and as the 475 comes on as it drives out. The 2 step, whether it's the launch or the rev limiter, shuts down the big turbo. I could do something about this but I don't really need to leave on more boost.

I don't have any good off the car pics. Here's an early one. You can see the WG outlet merging in on the top left, and I later added a second V44 on the right.

http://i116.photobucket.com/albums/o...k/100_1135.jpg

Manifold can be seen here, built by JMF.

http://i116.photobucket.com/albums/o...k/100_0895.jpg

Remy · Oct 15, 2009, 01:30 PM

Quote:

Originally Posted by kjewer1

The S475 is a T6 1.32 turbine, so it's massive. Hard to say when it spools though. I dynoed it once at 40 psi but I start the test at 6500 so it doesn't show spool. At the track the 2 step effectively disables the primary turbo so no data there either. I'd estimate full boost (40-45 psi) in the 5500 rpm range though. How much power is a trick question thanks to the auto trans. Best thing to do is just go by trap speeds and weight (155 mph at 2440 lbs). Last dyno was 586 whp on a mustang dyno, but that's obviosuly misleading.

Here are the first two runs on the setup.

http://www.youtube.com/watch?v=vhiKLm9E6UA

Som pics here.

http://s116.photobucket.com/albums/o...r1/RWD%20pics/

Wow I never knew your car was twin turbo.

kjewer1 · Oct 15, 2009, 03:29 PM

It's not, it's compound turbo.

This is new for this year, last year was a single 4294 with a 100 shot to spool. Both setups went 8.9 at 40 psi, which is interesting.

chuntington101 · Oct 30, 2009, 11:19 AM

Quote:

Originally Posted by kjewer1

It's not, it's compound turbo.

This is new for this year, last year was a single 4294 with a 100 shot to spool. Both setups went 8.9 at 40 psi, which is interesting.

Kevin, what advantages do you see with the compound setup over the gt42 and n2o set up? Are you times faster? Cheers chris

kjewer1 · Oct 31, 2009, 04:34 PM

Both setups went the same et at the same boost. The advantage is that I don't need nitrous anymore. The main reason I did it though was to learn about it. Once in a while you have to put down the keyboard and try **** to learn something significant.

sk8terdude929 · Nov 5, 2009, 08:40 AM

Quote:

Originally Posted by kjewer1

The S475 is a T6 1.32 turbine, so it's massive. Hard to say when it spools though. I dynoed it once at 40 psi but I start the test at 6500 so it doesn't show spool. At the track the 2 step effectively disables the primary turbo so no data there either. I'd estimate full boost (40-45 psi) in the 5500 rpm range though. How much power is a trick question thanks to the auto trans. Best thing to do is just go by trap speeds and weight (155 mph at 2440 lbs). Last dyno was 586 whp on a mustang dyno, but that's obviosuly misleading.

Here are the first two runs on the setup.

http://www.youtube.com/watch?v=vhiKLm9E6UA

Som pics here.

http://s116.photobucket.com/albums/o...r1/RWD%20pics/

All i have to say is WOW that thing flys, any more videos?

kjewer1 · Nov 5, 2009, 11:41 AM

Hmm. If you search youtube for kjewer1 and z06kait you'll find the bulk of what's out there. I don't think I have too much video of it on this setup though.

This one is from a track rental where I started practicing with the chute. http://www.youtube.com/watch?v=5fCJQyhYFgQ There are some interesting compound turbo noises after the burnouts and such, but infortunately she cut most of it out.

There are also a number of runs in some of the Showdown videos but I had to lift on every pass at about 1000 feet. The last run against the Dogbox evo shows it building boost and cutting a good light on a pro tree though.

chuntington101 · Nov 9, 2009, 05:42 AM

Kevin, how did you spec the two turbos? whats ratios did you use to get the 50trim and the S475?? also have you any planns on running a larger High presure turbo??

Cheers,

Chris.

kjewer1 · Nov 9, 2009, 06:05 AM

I planned on running the turbos around 2:1, so I sized them as such. The 475 is right about double the airflow of the 50 trim. I won't use up all of the turbo capacity at 45 psi (4:1), but they both end up moving some good air without working all that hard.

mikgsxx · Nov 9, 2009, 06:05 PM

that is bada**. i would like to see some numbers.

kjewer1 · Nov 9, 2009, 11:35 PM

With a powerglide and a GM 12 bolt the dyno sheets aren't very impressive.

Last time at the local mustang dyno (reads like BR's) it did 586 to the wheels at 40 psi. This is the same "power" it runs 8.9-9.1 in the mid 150s with.

chuntington101 · Nov 12, 2009, 12:24 PM

kev, at what pressure do you open the 2 gates for the small turbo? Is it the same pressure as the large turbo? Cheers chris