I am right when I assume from the posts I've read that all the vacuum pump does is run the wastegate solenoid? Isn't it used for anything else, the cdr for example?

Update your signature so we know what truck you have. LD models use the vac to control EGR functions and ECM has to read 20" vac at the baro sensor for boost control.

At the risk of sounding really stupid here, I thought that it also supplied

:iamwithst vaccume for the heater controls?

Not that I'm aware of.

Has anyone tried getting rid of the vacuum pump and running only a turbomaster for boost control?

I just did it yesterday and it's the best thing you can do to your truck, you might gain a couple of HPs also just from removing pump.

Great to hear that. So all the damn vacuum pump is used for is wastegate control? Who designed that system?

QM, thanks. Maybe I will take back my brand new VP and put on a turbomaster. I like the idea of steady boost:ro)

I've removed the pump from my '94 and my dad's '96 with great ease.

I'm glad others have seen the light and said goodbye to the pump. I though it freed up some ponies as well.

Ordered my Turbomaster this afternoon. I can't wait to try it. :grd: Does anyone have a part number for a shorter belt to bypass the Vac pump by any chance?

I found two allthread bolts and I deceided to make one of what wade said a boost controller for my dad's '96 with GM-7 verticle wg-arm turbo.

Guybb3. Are you sure you have a '96 1500 suburban 4x4?? To the best of my knowledge all 1500 suburbans are 2wd and all 1500 tahoe/yukon/blazer's are 4wd. If you have an "F" engine you should have a 2500. Your vac should go to the wastegate sol and the firewall map. There shouldn't be an "F" from the factory in any 1500's.

1500 Suburbans are 2wd and 4wd regardless of motor and year.

I've heard there are a few of the "misbadged" modles out there. Does it have 8 lug axles or 6? 8 lugs is a K3500 no matter what they labled it and the same if true of 6 lug 1500's.

I need to clarify 1500 suburbans from 1994-up that came with the diesel are all 2wd. 1500 Tahoe/Yukon/Blazer's from 94-up that came with the diesel are all 4wd two doors.

I don't talk about gassers-:tin this forum unless the thread calls for it.

Not entirely true, QM - 2500 is a 1500 frame with hd towing upgrades, with added 8-lug to get the larger brakes.
Early also got 4L60E in the 2500LD, with 4L80E optional, standad in 2500HD
Around '96, 4L80E became standard in all Diesel lines
LD got EGR "S", HD got non-EGR "F"
2500HD had FF rear axle as optional

3500 gets larger, heavy-wall frame, 8-lug FF axle

2500 LD axles are 6 lug 9.25" on a 1500 frame on the 90's models though that's changed now.

There's not a lick of difference in the K2500HD and the K3500 I have 'cept mechanical/EFI, stick/auto x-cab/CC everything else is "lo mismo". I did notice '95+ got an improved A-arm though.

My son in law had a '96 K2500 GMC Suburban 6.5 TDiesel, and as the K stands for was a 4x4. Unless only 1500 diesels were 4x2, I've seen plenty of K 4x4s around here.

But you could be right, they might be all 2500 not 1500

Anyway, I just noticed it... GMCTD what does 6wd means on your signature ?

I hope you don't have a 6x6, it's got to be a monster.....:eek:

dually's have 6 tires and he made his 2wd a 4 wd.

So if I put same rear wheel arrangement on front of my truck do I get a 8wd ??? :lol: I figured that he meant a dually, I was trying to give him some hard time....it's good for your hart and soul sometimes, unless we are married with children, then it doesn't bother much anymore, we are used to it.

You guys who take the vacuum pump off and use the TurboMaster alone are losing a lot of potential from your trucks. The vacuum system is not that bad of a control system, just has a few reliability issues.

There are several areas of operation where the factory contorl system is much better than a spring loaded back pressure regulator, which is what the TurboMaster is.

You all do what you want, but I won't be going that way.

RJ, a spring gives 100% wg closure 'till EBP's rise above closure tension and it starts to groan, couple that with the elimination of low % WGDC function from the PCM (stock programm issue), and the shorter belt turning less mass, and the vac can't stack up to that.

Now factor in the fact that you've not run the TM without a vac pump and you're running on empty.

Sorry it took me so long to answer, MDT, but yes my truck is a 1500 4x4 with 8 lugs. I go through this all the time when I go to get parts, especially brakes. I always tell the parts guys I have a 2500 so I get the right stuff. I have never had anyone able to tell me what the real difference is between a 1500 and a 2500. As far as I can see, there is no difference whatsoever. All the parts I have seen interchange. Also, when guys are doing a parts search once they put in 6.5l for an engine, the search computer immediately switches to all 2500 stuff regardless of what you put in for 1500 or 2500. My truck also does not have egr either and the vin says F. Thanks for all the help guys, especially you QM. The vacuum pump will be leaving my suburban before we take the long april trip to Virginia.

Ordered my Turbomaster this afternoon. I can't wait to try it. :grd: Does anyone have a part number for a shorter belt to bypass the Vac pump by any chance?
I can't remember the part numbers right now but you need 2 sizes smaller. (the last number is the part# before the zeros needs to be two lower)
For '94 and '95, you can just have them look up a belt for a '93. For '96 and up it is shorter.

RJ, a spring gives 100% wg closure 'till EBP's rise above closure tension and it starts to groan, couple that with the elimination of low % WGDC function from the PCM (stock programm issue), and the shorter belt turning less mass, and the vac can't stack up to that.

Now factor in the fact that you've not run the TM without a vac pump and you're running on empty.
You guys start reporting your boost numbers with the TurboMaster. We'll see.

I've argued this point before, ad nausium, but it is becoming pointless. My experience with the electronic/vacuum system tells me that I can operate at higher boost levels than what the TurboMaster will allow, based on the posts I've read here and elsewhere.

It's fine with me if you guys go that direction. I really enjoy being out in front of the herd.

Ok, my boost numbers with the vac all time peak was 15 psi and with a spring I can push 19 psi without trying, all time peak, 750*F EGT's and 21 psi on a cold day. I've helped billbenn to fool his MAP he had a TM already installed and was then was very happy with the test drive, as each time he hit a new psi it brightend his smile, Billbenn hit 17 psi sustained uphill in od after I fixed him up resisters for his MAP. no vac pump.

I can easily peg my 15 PSI guage, and I have some more adjustment on the spring.

You guys start reporting your boost numbers with the TurboMaster. We'll see.

I've argued this point before, ad nausium, but it is becoming pointless. My experience with the electronic/vacuum system tells me that I can operate at higher boost levels than what the TurboMaster will allow, based on the posts I've read here and elsewhere.

It's fine with me if you guys go that direction. I really enjoy being out in front of the herd.
I didn't really notice a lot of difference in the boost after I installed the TM except I got a lot more turbo lag. (If I floor it from a dead stop, I get a cloud of smoke out of the exhaust instead of the tires)
The boost fluctuates just the same as it did with the vacuum controller.
To fix the lag, I cranked the spring way in but lost some top end power from too much ebp.
If I was going to do it again, I would wait till the vacuum system broke to get a turbomaster.
If someone would make a mechanical controller that worked off boost pressure instead of back pressure, I would switch.

I've run sustained 19 psi with the vacuum system. Off idle, the wastegate does not open. There is more there too. Like I said, have at it. I'll stay out front.

I did lose some off idle performance at some point in the improvements I have done this year (I did Heath's program first with a weak vacuum pump and and then added the TM). I also noticed a loss of off idle performance when I moved here to Denver, due to the thinner air. I feel I got back some of the lost off idle power last week with the deletion of my muffler.

One of the main reasons for me getting rid of the vacuum pump is the same for most. I was looking at replacing the pump for the second time in 2 years. TM looks to me to be more durable, and one less item to fail on one my long road trips.

guybb3,
I've seen when some of the 1500 GM vehicles that have the HD package, they came stock with the 8 lug set-ups.
I can relate to your parts store dilemas due to what/who they hire. Knowledge factor is not usually an issue.
Mark

Yeap Ya are right You can get a 1500HD ( 8 lug) or a 2500LD (6 lug) and couple of combos in between.

I"m afraid the problem is further spread than local parts houses, I find the dealership guys to be just as lost as they are. No matter where you go, if you say the word 'diesel', you get the 'oooooooohhhkay' response, you know your in trouble.

I"m afraid the problem is further spread than local parts houses, I find the dealership guys to be just as lost as they are. No matter where you go, if you say the word 'diesel', you get the 'oooooooohhhkay' response, you know your in trouble.it's like that when you go to the gm stealer and ask for parts for these trucks.

GOSH I must be D**n luckly then. I have always been able to find dealer ship parts people that work real well with me and searching out my request. I find good counter people at local stores to. May have something to do with my years working the counters myself.

I find it takes some patience to go through the parts counter search for my parts but if you bring part numbers it cuts the time in half.

I only go to the dealer for schematics or for a dealer only part. I did find one place her in the area that has genuine GM parts for a reasonable price and they have some knowledgable people there as well. As for Autozone and Advanced Auto, they need an abundance of assistance when trying to get what you need. Most of the time, they have what you need, you just have to educate them on where to find it and how to get it.
I have learned both of those companies computer systems to the point of when I walk in I just get on and find my own part #'s and tell them what I need for them to go and get.
Ya gotta figure, in place's like that they are not going to hire ASE mechanics on their budget.
mark

TDG,
Yes you are correct in regards to some of the dealers being clueless as well.
mark

I'd put my turbo master up against any truck with the same mods, with vac controlled waste gate. People who drive my truck ask me if I swapped in a D-max. They refuse to believe it's a 6.5 until they see it.

To the 1500/2500 issue if your not the original owner there is the posibility that the doors were swapped from junk yard with whatever badging came on them. If you have 8 lugs on a suburban it IS a 3/4 ton, reguardless of engine/tranny/axles/4wd/2wd.

I'd put my turbo master up against any truck with the same mods, with vac controlled waste gate. People who drive my truck ask me if I swapped in a D-max. They refuse to believe it's a 6.5 until they see it.

To the 1500/2500 issue if your not the original owner there is the posibility that the doors were swapped from junk yard with whatever badging came on them. If you have 8 lugs on a suburban it IS a 3/4 ton, reguardless of engine/tranny/axles/4wd/2wd.
You're on!

RonnieJoe, your a little far away for a head to head drag, so we'll have to do this with dyno's and drag ET's. I'll look for a dyno this weekend, the only one in my immediate area is an elevated indoor dyno my lifted Tahoe doesn't fit between the dyno and the roof, but I'm still looking.

Maybe we should start a new thread as this has gone way off the original topic, no matter how fun it is!:cool:

It doesn't appear to my untrained eye that ya's truck are even close to having the same mods/upgrades. It will be like apples to grapefruits for a comparision, won't it?

The biggest difference is the aftermarket chip, which doesn't drop the WGDC like a rock, above 8 psi. Guys running their stock program are at a disadvantage using the vac pump, unless they have a fooler or chip or both to keep WGDC up to 99.97%, other than that and an IC, his trucks pretty much stock.ie turbo, cr, stock inlet diameter.

Ok So are they looking for the power compare are the amount of boost they can hold. That IC makes a big difference in power so still not a good compare to each other and has little to do with which wastegate system works best?????? That could best be done on the SAME truck by switching for one to the other and redynoing,<is that even a word, wouldn't it ?

Oh heck, let's all get charge air cooling and we can have something of a level playing field to evaluate boost psi as the IC lowers pressure somewhat.

IN case anyone here is interested 16TQ has a GM-8 he is wanting to sell badly. He can be found in the classifed section. I have been talking to him about it for a couple of weeks and decided to not start any Mods right now. I told him I'd pass that out over here too.