Yellow Bullet Forums banner

1581 - 1589 of 1589 Posts

·
Registered
Joined
·
239 Posts
WG that dumps to atmosphere is controlling the big turbo, not total boost to the engine (that's the small compressor). The small turbo's gate references the intake manifold (total boost), the big turbo's gate references big compressor outlet pressure (between compressors).
Could draw a schematic of how the WGs are being plumbed to the sensing and the boost controllers?

Please!

s.r.
 

·
Registered
Joined
·
1,580 Posts
Discussion Starter #1,582
Every time I try to draw a picture of this I want to smash my laptop. Let me try a more thorough description one gate at a time.

Big turbo (LP) gate: Off the manifold collector, dumps to atmosphere. There is a boost reference line from the LP turbo's compressor cover to the WG's lower port, with a Hallman MBC inline. I also use a minireg to put up to 40 psi to the WG's top port to help keep it shut at high boost (this gate will see full manifold back pressure to atmo pressure differential across its valve, huge pressure differential wants to open it when I'm trying to go fast and shit).

Small turbo (HP gate: Also off the manifold collector. Rerouted to hot pipe between turbines to feed the large turbine. Intake manifold pressure line to the gate's lower port through a Hallman MBC. Big/LP turbo pressure to the top port (or HP compressor inlet pressure, same thing) to reinforce the spring and cause the HP turbo's boost (total boost) to come up 1:1 with the big/LP turbo.

There are pros and cons to this strategy, but that's been covered somewhere.
 

·
Registered
Joined
·
179 Posts
Motion is not a requirement for work. You can put 745.7 watt (1 HP) into a light bulb and there is no motion. You could also heat up your leftover dinner in the microwave, the food is hot, yet no motion. Work is being done.
We are talking about mechanical work not electrical.
 

·
Registered
Joined
·
245 Posts
Work IS the motion of energy. Power is the measurement of the amount of work. They are slightly different. Work doesn't require direct motion. heat transfer is considered work. Your microwave example is FULL of motion. You have the elections flowing through the transformer. You have the microwave radiation emitted through the air. You have the atoms I'm your dinner vibrating at a higher frequency as they are excited by the radiation. You have the thermal radiation waves of the food as it heats up.


Kevin,
Have you discovered an idea compressor size ratio? I'm seeing a 2:1 mass flow rate ratio a being pretty ideal, but basically following the rough formula of (hp mass flow) × (lp pr) = (lp mass flow) and using lp mass flow × .8 = hp required mass flow, to get rough numbers
 

·
Registered
Joined
·
239 Posts
Thanks for all the great help, so now comes another stupid question, I'm hooking up boost control, I plan on using a simple boostT on the hp and electronic controller on the lp.

Is this a good method or am I backwards or left field? Should I maybe use two electronic controllers?

TIA
s.r.
 

·
Registered
Joined
·
1,580 Posts
Discussion Starter #1,586
Kevin,
Have you discovered an idea compressor size ratio? I'm seeing a 2:1 mass flow rate ratio a being pretty ideal, but basically following the rough formula of (hp mass flow) × (lp pr) = (lp mass flow) and using lp mass flow × .8 = hp required mass flow, to get rough numbers
I've always used the 2:1 mass flow rate rule of thumb I came up with in ~2009 and it's never let me down. It seems to always work. And I've also worked with setups that deviate significantly from that and some of those work great too. In the end, WG/boost control is much more critical than turbo matching IMO. But the better the turbo match, the better the potential results once you get boost control working.


Thanks for all the great help, so now comes another stupid question, I'm hooking up boost control, I plan on using a simple boostT on the hp and electronic controller on the lp.

Is this a good method or am I backwards or left field? Should I maybe use two electronic controllers?
I run a pretty simple boost control setup on my car. One mini regulator and two Hallman MBCs. Works beautifully. It doesn't have to be fancy, as long as it does what it is supposed to (that's a longer story, but it's been covered here).
 

·
Registered
Joined
·
1,580 Posts
Discussion Starter #1,587
I finally got a chance to pull the turbos off of the 2g to check the damage. The last time we tried to take it out to NED I found the small turbo compressor cover had popped off the small turbo. There are at least two possible causes for it popping off. We know this compressor cover hits the trans, and as the hot side gets hot and expands, that should get worse. Also, with the 60mm gate suspected of blowing open and limiting boost I keep turning u the boost on the big turbo, so that could be trying to pop the small cover off as well.

Looking at the parts, the only place the wheel touched the cover is directly opposite the witness mark where the cover hits the trans. No surprise there I guess. The wheel and housing damage is pretty small, I'd toss this back together and run it but it looks like the shaft may be slightly bent. So it should go back to Forced Performance Turbochargers for a do over.






And looking at the gate for the big turbo there's no gasket here and it's clearly leaking. That turbo always seemed reluctant to come up, I have to wonder if this was a factor. I remember finding this years ago when I went to change springs on the dyno one night, forgot about it, and found it again, lol. I also have to look at the possibility of the small turbo's internal gate (which is welded shut) leaking, I never noticed before that that flapper is open to atmosphere. 20 years ago we used to cut out new gaskets with that portion left solid to block off that hole. That way, if the gate leaks, it's still sealed at the gasket as a backup.




I'm not sure yet what I want to do about this setup. On one hand I'm tempted to throw a single 62mm on there and let Katie do some racing. But that will require a new manifold and a converter. On the other hand, this setup is pretty close. If I can get the small turbo fixed and clear up that interference with the trans, and get the boost to do what I want it to, it's on the brink of going 8s. And Katie does like this setup. At any rate, next step is to pull the trans.
 

·
Registered
Joined
·
1,580 Posts
Discussion Starter #1,589
I considered putting a 62mm on it to race True Street at WCF and FIS at Import Face Off events. Ideally the 62mm would just be the small turbo, and I could swap it between a downpipe for 62mm racing and a big turbo for compound turbo stuff. But when 62mm turbos run mid 8s, I'm not sure how much quicker we'd even want to go with this thing.
 
1581 - 1589 of 1589 Posts
Top