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The forced air induction\more fuel thread...

Well 6.2 turbo, I gave it another go today with no luck. I tightened up the governor spring and put it in the new pump. When I had the pump in, I blew air into into the inlet at the back of the pump (about 80 psi but I couldn't get a good seal). I then cranked and cranked and she wouldn't fire. So I pulled the fuel line and blew some more air in and tried again with no luck. So I can only think of three things:

1) Loose plungers letting fuel by
2) Plungers are still stuck
3) Delivery valve adjusted too tight and not letting fuel by. The PO of the pump said he did not mess with the delivery valve screw so I didn't touch it, especially since I don't have any way of getting the screw torqued to the right spec.

Anything else I could have messed up? Anything on the top end?

Any help is appreciated. If I can't get the pump running tomorrow or monday, I will pull the pump and probably send it to a pump shop so that they can at least determine if the pump will even pump fuel.

Thanks guys
 
Did you check how tight the plungers fit ? Also if you had them out you may have gotten them switched,some times it matters,sometimes not. The delivery valve is not adjustable,it could be stuck,or have dirt in it. The plungers can fit pretty loose,and still start cold,if the head and rotor fit is to loose it won't start ever. I polished my plungers with wheel polish,after they seized .
 
Well I didn't check with any sort of measurement but they felt like they were as tight as the originals in their bores. I hadn't thought of the plungers being in wrong, but I think he put the same radiius on each end so they were uniform. It could possibly have been the delivery valve, I will have to check. The head and rotor should fit fine as the pump is supposedly almost new, but I cannot verify that. I mean I can try putting the big rotor in the head of the old pump but I would imagine that probably wouldn't work at all.

I may try one more time tonight but most likely the old pump is probably going back in again for now ha.
 
Does anyone know what hp a normal turned up db2831 pump can make ? I've been thinking of maxing my stock pump,the best I can, and getting it dynoed. This imformation could be very valuble ,and might surprise some people.
 
I would be interested too in a dyno run like that. I have heard a turned up db2831 pump (stock) won't do 300 hp at the wheels, which makes sense, thats like 150 hp over stock. I would be impressed if it could do 300 at the crank. With mine maxed out I was not overly impressed, but I believe my old pump has seen better days...

But honestly I really don't know. I wish dyno runs weren't so expensive so I could dyno mine all the time ha.
 
vdb11 said:
I would be interested too in a dyno run like that. I have heard a turned up db2831 pump (stock) won't do 300 hp at the wheels, which makes sense, thats like 150 hp over stock. I would be impressed if it could do 300 at the crank. With mine maxed out I was not overly impressed, but I believe my old pump has seen better days...

But honestly I really don't know. I wish dyno runs weren't so expensive so I could dyno mine all the time ha.
Click to expand...

a db-2831-4911 is capable in stock trim(not turned up) is rated for 25hp per cyl, so in theory it could be maxxed out and possibly make 35-40hp per cyl. but these numbers, i would imagine would be based on a shiny new tight pump... not a 120000km and over pump... so when a person goes to say a 2833 pump, it is possible to break 300 RWHP.... chevydiesel has done it already... and i would not be suprised if 6.2turbo was not seeing mid 300's in his u-tube video....( after it warmed up and started spoolin)... keep in mind that those people saying it was not possible were still running the bottle-neck gm turbo which fall flat around 200hp...
 
For some reason the Tahoe seemed to be starving for fuel. I'm hopping it's mainly the governor. Once its up and running again I'll start a thread on all my adjustments. This way I can go back and check what did what. On my 6.2 I made so many changes,that sometimes I forgot what order they happened. It also adds to the confusion,when making multiple changes at once.
 
Agreed turbonator. I think an 831 pump is just a little shy to break the 300 rwhp mark. I am guessing my 839 pump would support 400 hp at the crank (If I can ever get it running!) but that would only be with the right supporting mods, some of which I do not have yet. I think my turbo could get me close, but I still need intercooling, a better exhaust system (which I am serious about pursuing), and water/meth.

I need to start documenting my stuff too. I am going home again today to help get 4th cutting hay finished up I may get the truck running before work tonight. I may just start out with the original worn 831 pump with the screw tight and original governor spring, and then go step by step from there, maybe I will steal the video camera we have at home, no one uses it anyway :)
 
turbonator said:
"""""VIDEOS"""""......


good stuff that, saves us money renting movies....LOL.
Click to expand...

:hihi: Agreed.

So after pulling the new pump again tonight I put the old one back on, the screw is pretty tight, so it is pretty much maxed out. I tightened up the gov spring like you said 6.2 and it worked, in fact the idle was almost too low to run the truck, but I just adjusted it up with the screw on the throttle linkage. Funny thing though I went for a real quick test drive, shut it off, and 20 minutes later I started it back up and it idled at 500 rpm ( a bit lower than I had set it) and it sat there and blew white smoke like it does on a cold start until I adjusted it back up to about 900 rpm.

I think I have the governor too tight now. Before it was very snappy but didn't want to return to idle. Now there is a dead spot/lag in the pedal and it returns to idle very fast, a bit of a nuisance on a standard. She accelerates ok, I didn't get to see where the gov stops it yet. Overall still not overly impressed with the pump maxed out. I think I might have the VGT spooling a bit too slow as well. Oh well learning something new everyday :)

Thanks again for the help!
 
Well,my HX 52 refuses to light. It spools gradual. So far I'm not impressed . I think it should light with the amount of fuel it has. I might try a smaller diameter crossover pipe,and more fuel. If it would light at 2000 rpms,it would feel awesome. Guess I could put a HX 35 on,these light around 1800.
 
We were looking at a Bosch p-pump yesterday at the "parts yard", pump from a 70's 9.0L Navistar V8.... the little that we were able to find about it so far, stated that it should be able to attain 70hp per cylinder..... it is very long though, would fill almost the whole length of the valley on a 6.2/6.5L.....
 
That is what Bill Heath had on a 6.2 years ago. They turn the wrong way,so he had a custom gear box made. Another pump would be the 3208 Cat. This one is fairly large,but not as long. I will get enough fuel eventually.
 
I too have heard about using the 3208 pump, in fact I looked into it a while back, I would love to see someone do it. I am assuming since Bill does not run the P-pump anymore (or does he?) that he found it was not worth it?

I also noticed many John Deere tractors use a Stanadyne (or Roosamaster) pump, but they run much less HP, I wonder what one of those would be like?

Also another quick question guys, I am about to start an IAT/EGT experiment with intake tubing. I am going to try running the tubing behind the radiator like Don did (except he did his because thats the only way he could run it), and then maybe a heat dissipating pipe in different combos getting data each time. I would like to get the IAT gauge and tubing ordered this week. So my question is do you guys think 2.5" tubing would hurt airflow alot compared to 3"?? I have 3" tubing on it now, and I think 3" will run the way I need it to, but the 2.5" will just make things alot easier. What do you think?
 
I ceramic coated my F intake 2 reasons,

1) intake went underwater during Katrina and I did not want the salt to leech out of the aluminum forever so coating would stop that.

2) I thought the ceramic might make a difference with the charge air temp reduction overall, I didn't really see a big change with IAT much on my truck, but as I type this, it may be doing more than I think, because I can run WOT without WMI or IC and not high IAT defuel on the truck, my burb has stock intake but also ATTd has high IAT defuled on me once but I was trying to get top end out of it making 107mph before the defuel.

So long as your ID of pipe is same as what turbo exit & intake inlet is should not matter, possibly upsized pipe 3" between the two can cause a minor flow change where it goes one to other, probably not enough to really matter, but I'd keep same ID all way through to keep flow laminar as much as possible, same reason as you don't want too many harsh bends in the plumbing runs.

Cheap source for pipe for R&D is exhaust pipe, & you can weld a bung into it for IAT readings, try it wrapped & unwrapped with header wrap to see if that makes a difference as well.
 
The turbo outlet is kinda like 2.75", but 3" coupler works fine with a small spacer, and the intake inlet is 3" (its a Peninsular upper). I might just go with 3", still kinda on the fence on that.

Also, where do you suggest getting cheap exhaust pipe? I was going to use polished aluminum pipe from frozen boost, as I thought their prices aren't bad, and would look nice. I have gotten exhaust pipe from NAPA but the price of exhaust pipe from them is just absolutely ridiculous. Advance doesn't have 3" pipe, and bends seems to be expensive. If I can find somewhere to get exhaust cheap I will definitely use that.

Speaking of IATs, what can I use for a gauge? I plan to just tap it into the upper intake, but the gauge that frozen boost has is apparently no longer available. I want something cheap for sure. Would a water temp gauge read air temperature? I would assume a pyro would work but they go too high and they are way too expensive for this purpose.

Also good thinking on the ceramic coating, was it expensive?
 
I use my MT2500 but have also used my remote temp sensor hooked to my DMM I got at Sears that looks similar to this http://www.fluke.com/fluke/usen/accessories/temperature/80bk-a.htm?PID=55348 but has stand alone module to work with any DMM.

This allows me to hook it up under hood and add pigtails from the module output into the multi-meter in my cab and read temps, since it is a K thermocouple with module underhood you don't change the temp value with length of wire like you can when using a RTD & then having to go to a conversion chart for resistance over temperature.

Depending how deep you want to go into temperature monitoring meaning $$$$ :D http://omega.com/ has all kinds of sensors to play with for remote monitoring the one I got from Sears was inexpensive enough ($50 maybe 8 years ago) way for me to go with my DMM, plus gives me capability of testing a whole range of temps on things like freezers, ACs, bearings etc. vs a dedicated sensor for 1 location.

As for exhaust pipe source any auto part house will have the pipe you aren't looking for a long length, and not too expensive, when you settle on final diameter/length then spring for "pretty" chromed pipe, right now for R&D you want something you can dril/tap/weld sensor to, maybe even a boost tap as well as IAT tap for now test wrapped & unwrapped tube to see changes with temperature.

has been on my plan last 2 years to get back into R&D data acquisition mode, but new job/s have precluded me in doing much beyond driving my beast and maintaining it.
 
Had my whole intake upper & lower coated for $275, I was fortunate as Jet Hot used to have a shop in town, after hurricane Katrina flooded them out, they never opened their shop back up :(

Which sux as I wanted to ceramic coat the entire turbo, that couldn't happen now without shipping off to a shop that does ceramic coating; so I settled on a Walking J turbo blanket which has really helped with underhood temps.
 
I have heard alot about those blankets, I wonder if I could find a reasonable one for the VGT, I know they have cheapy ones on the big site, I wonder if anyone has tried one.

Tim, what does that sensor plug into? What is a DMM? Remember I have no sensors at all from the factory and I am running an aftermarket upper intake, which is why I was just looking for a simple gauge with its own mechanical or electric sender. That Omega site is pretty cool.

I will keep an eye out for cheap pipe, I might shop around this week if I get time. Thanks Tim.
 
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