Twins Owners- Gauge questions.

[Fishin Guide]

I am curious what gauges you use in your trucks to keep an eye on everything. What type of gauge, what range, in what location for the measurement?



I am talking about boost gauges and I know guys have planted thermocouples to get more data. Just looking for a firm understanding of the what and why.



Thanks!!



Dave

 

[WDimig]

i have a 60lb. gauge from isspro, i dont have twins, but still see 50psi reguarly. i think isspro also make a 80psi gauge as well.



wes

 

[Idaho CTD]

I've got two DiPricol 100psi boost gauges with tattle tails I use for testing. One in the cold pipe and the other for manifold pressure. Anything over 50psi is overkill in the cold pipe for most people though. I like the tattle tails so I can watch other gauges while tuning and then go back and look at them later.

 

[Fishin Guide]

I've got two DiPricol 100psi boost gauges with tattle tails I use for testing. One in the cold pipe and the other for manifold pressure. Anything over 50psi is overkill in the cold pipe for most people though. I like the tattle tails so I can watch other gauges while tuning and then go back and look at them later.

Thanks!



Dave

 

[Fishin Guide]

BTW, what is the optimum size boost gauge? Say a truck that should never see more than about 65psi? Would an 80 psi gauge be adequate, or should I jump right to a 100 psi. I have both options in IssPro.



I guess I can use my 60 pounder for the cold pipe. Can it be hooked up in a trick (hidden) fashion other than in the pipe itself? Possibly the inlet of the turbo housing? Or will this reading be skewed due to the potential pressure drop at the throat of the charger?



Thanks again!



Dave

 

[SRadke]

I had three gauges Dave. Cold pipe, intake horn and exhaust manifold. The drive pressure is good to have while tuning to help set up a wastegate and also nice to keep an eye on your exhaust brake (if you decide to put one in). I had the cold pipe and intake horn plumbed to a dual digital gauge from SPA with high value readback as Nathan said, that worked well for me. Unfortunately it's like pulling teeth to get products out of SPA because I really like the gauges.



-Scott

 

[Fishin Guide]

Thanks Scott.



I need you to drop me a PM regarding the finer points of wastegate tuning vs drivepressures.



I have another boos gauge on the way and I have access to a "loaner" so checking everything should be easy enough. I just don't want to have 100 gauges in the truck.



Thanks again guys. Great info!



Dave

 

[SRadke]

I'm not the right guy to educate on that subject, all I did was trial and error. That's the nice part of having a bunch of gauges, you can actually tell what's going on... . if you can read them all fast enough lol. I almost stole a laptop with a data aquisition system from work so I could log it all and review later but I decided I didn't need it that perfect.



Just try some diffrent things with your wasegate. Use some version of a boost controller set at various positions. I like to push my wastegate open with boost from the cold pipe. That way it stays closed until the big charger get's rolling. If I'm towing heavy with the fueling turned down I'll clamp that line off so it'll build more boost on less fuel. The variety of things you can do with twins is amazing.



-Scott

 

[Fishin Guide]

I hear ya Scott.



I am planning on a boost controller. Something like Ponci's. That should give me even more combinations to meddle with.



But by and large, are there any good starting points for getting the system on the street afetr the install?



For instance, say you are using an internal gate. Modified for twins of course. Where do you set the boost pressure to start creeping? 20 psi? 24 psi? more? way less?



I have a good understanding of the basic function and the dynamics of the system. I just want to minimize initial tuning so that I may do honest and thought out testing.



And then Summer fuek wil come along or some altitude and goof me up yet again!



Dave

 

[SRadke]

From my meddling... . I'd say 20-22 is a good starting point. Depends how much fuel your running, what chargers, and how much max boost your looking for but I'm guessing you'll use the same primary I am in the ~500 hp range so 20-22 should be a good starting point.

 

[Idaho CTD]

When you hit the sweet spot of a twin set up the back pressure and egt's will be the lowest and the boost generally will be the highest. With a 35/40 hybrid you'll have more back pressure then Scott did so you'll most likely need to open your wastegate sooner for optimum performance.

 

[swankmetal]

i'm not trying to hijack here, but i'm going to put a dyno sheet on here with my wastegate set somewhere in between 18-22. maybe somebody can tell me if that's why there is a slump in the graph?



[/IMG]#ad

 

[Fishin Guide]

What is the procedure to properly setup a wastegate?



I assume a regulated air source. Adjustable boost elbow?



If using regulated air, what pressure are you using? Or do you ramp up until the gate opens?



Thanks again guys. This is much appreciated!



Dave

 

[swankmetal]

If using regulated air, what pressure are you using? Or do you ramp up until the gate opens? Dave

that's what i did. i'm working on a variation of the ol' PBC that will be adjustable in cab right now though. with a resolution of . 1 psi.

 

[Fishin Guide]

that's what i did. i'm working on a variation of the ol' PBC that will be adjustable in cab right now though. with a resolution of . 1 psi.

I'm sorry, I'm a bit slow. Are you talking about a boost controller?



If so, I think I understand what you are saying. My question is, How do I set up my gate in the truck to perform propery?



Dave

 

[Diesel Freak]

With a OEM HX35 wastgate, well, you will just have to play with it.



With a good external, you would use differential pressure to operate it.



Gages? 0-100 psi for total boost, and 30 inHg to 30 psi for the primary. If you ever see vacuum in the cold pipe, you either need to slow down the top turbo or speed up the bottom with changes in exhaust housings.