#21  
Old 06-20-2011, 07:54 PM
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Sensors have a range where they are accurate, Typically in the middle/two thirds area.

Reading OVER 70 on a 75 range, says that you might be 80 or higher in reality.

All of the back-pressure is not helping the EGR EFFECT inside your engine diluting the next charge. So whose waste-gates are you presently running?

It appears that you have plenty of energy to spin the compressor wheels at a lot less turbine in pressure.

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  #22  
Old 06-21-2011, 12:33 PM
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Running turbonetic nex gen gates - I dont plan on running 30lb of boost so if I keep it down the back pressure is going to work for me as it stand's now - on my car - the ratio is about 1.6 to one untill the boost starts working up over 25 lb -- then the back pressure seems to ramp up pretty fast

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Old 06-21-2011, 03:05 PM
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Curt, I'm curious what your rpm and boost level is at launch?

Seems to me you could run a much larger turbine wheel and greater A/R and still spool fast enough. Even 1.6 differential is alot for a drag car. (You are reading intake manifold pressure vs turbine inlet pressure correct?)


Last edited by BruceWilkie; 06-21-2011 at 03:10 PM.
  #24  
Old 06-21-2011, 03:34 PM
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launch is 5200 and 10 lb -- with a quick ramp in and yes - back pressure to manifold pressure - we have up graded to a larger turbine wheel and modified housing - but it looks like it wants more - -damn

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Old 06-21-2011, 04:17 PM
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Quote:
Originally Posted by cgeise View Post
launch is 5200 and 10 lb -- with a quick ramp in and yes - back pressure to manifold pressure - we have up graded to a larger turbine wheel and modified housing - but it looks like it wants more - -damn
Time to make room for some BW sx 500's (T6 flange). 80-98 mm inducer available. Ratings from 1250 to 1850 hp each these have a 111mm turbine wheel and several a/r choices from .85 to 1.6.
There are some s400 series (t6) that support up to 1350 each along with customized BW s400's that support up to 1575 each. They use 83-96 mm turbine wheels 1.10-1.32 A/R's.

Just a thought anyway.

My apologies for jackin the thread.

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Old 06-21-2011, 04:34 PM
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We did up grade the Precision 88s on the turbine side to an 111 wheel and had the housing modified to match - its better - but is not perfect so Id say your on the right track - anyone got any money ??

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Old 06-21-2011, 07:42 PM
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Still think that you have plenty of energy, adding a second set of gates would remove some of the excess pressure (1.6 ratio) and still allow you to use your existing turbos.

25 psi and then the second set of gates open up using a co2 bottle, a control valve and a pressure switch.

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Old 06-21-2011, 08:51 PM
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Gee Tom I was thinking of more gate(s) myself. Maybe put a balance tube between turbines and mount gate(s) on the tube.

  #29  
Old 06-21-2011, 09:09 PM
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Balance tube would work if the entry for the balance tube was in the previous location of the wastegate. You must put the wastegate in a branch of a Y with the bottom leg of the Y feeding the two upper legs of the Y. Right leg of the Y goes to the turbo. Left leg of the Y goes to the wastegate or in your suggestion: balance tube/wastegates.

That would be the plumbing for one side of the engine.

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Old 06-22-2011, 02:27 PM
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As it is now - the gates are CO2 controlled and will control the boost level very effectivley - by adding more gates are you just not reducing flow to the turbine wheel and as a byproduct reducing backpressure??

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Old 06-22-2011, 08:41 PM
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Quote:
Originally Posted by cgeise View Post
As it is now - the gates are CO2 controlled and will control the boost level very effectivley - by adding more gates are you just not reducing flow to the turbine wheel and as a byproduct reducing backpressure??
Thats the theory. Once spooled it doesnt take as much energy to maintain boost as it did to get it there quickly. A larger AR allows more past the turbine thus reducing backpressure. However it does so at the expense of increasing spool time.

  #32  
Old 07-14-2011, 06:16 PM
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88mm turbos are in!
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  #33  
Old 07-14-2011, 07:10 PM
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Nice...Christmas in July!

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  #34  
Old 07-14-2011, 08:50 PM
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The Turbonetics Turbos will work very well for you.

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  #35  
Old 07-20-2011, 05:29 PM
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RA-V Heads are almost done!
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  #36  
Old 07-20-2011, 05:43 PM
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Quote:
Originally Posted by taff2 View Post
Couldn't you bypass some of that backpressure through the wastegates? Back in the day,turbo drag racers used to use small turbine housings for quick boost response and then run a lot of the exhaust gases through the 'gates.
I wanted to ask if you could stage twin turbos like that. Run a small turbo to get off the line that by passes at something like 10lbs into a larger turbo. I always thought it would over spin the small turbo though. Anyone know if it works, I think I have seen an import do something like this but not at the scale I'm talking about.

sorry to jack the thread I have been meaning to ask, and didn't want to make a whole post about it.

Thanks Shad


Last edited by thirdgen455; 07-20-2011 at 05:49 PM.
  #37  
Old 07-20-2011, 06:25 PM
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3rdgen I'm thinking appropriate sized turbine wheel for the compressor you are running but smallest A/R housing for it to get max response. Then two gates one to limit boost based on intake pressure the other gate referenced to exhaust back pressure to keep exhaust pressure at or below intake pressure. The exhaust pressure reference line would likely need to be a hard line and long enough to coil to let it flex and help disapate heat. I dont know if you could disapate enough heat to prevent damage to the extra gate. Seems like it could work but dont know if its ever been tried.

For what I'm building I dont want too much boost off the line and will just size my turbine(s) to favor mid thru top end.

  #38  
Old 07-20-2011, 06:36 PM
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I was thinking on an inline six, I have rode in a few 1000hp supras down here and the big problem I see is that they have no power on the bottom because they are running the very large T88-34D - GReddy turbo's. you may have seen some run like 11 in the 1/4 with a MPH of a 9 sec car. If they could run a small TD06 before the big turbo and it wouldn't burn up the small one it could fix some of the huge lag problems.

I don't want to do it on a supra but if I could make a ohc cammer stay together I would love to go play with the supras with a 40+ year old engine. I figure with drag coefficiency of the 3rd gen I might be able to topend a few bad supras around here with a bunch of junk. well thought out junk, but still junk.

  #39  
Old 07-21-2011, 08:05 PM
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A few more pics.
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  #40  
Old 07-21-2011, 08:07 PM
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More Turbo Pics
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