Yeah - clay's def one of, if not the best for parts.

And I'll have to keep an eye out for the stock plenum seals if I stay with them. I'm thinking ill pressure test them now and stick with them for now, the. Upgrade later if needbe. Doesn't seem to be too hard a job with the engine in the truck...

And, seriously - thanks for all the feedback. It's definitely very helpful in putting my plans together.

Oh, one more question for now - I was looking closer at the turbo I have and the wastegate is connected by a rod to a cylinder/disk with a grease fitting on the back side. Doesn't seem to be any direct oil connection to it, or electrical harness. How are they connected up in the SD truck? Are they completely passive devices, or is there some engine control?

And it looks like it would be easy enough to gut the wastegate and plate it over. Obviously over boost could be a problem, but with a chipped PCM, I'd think it could work. I don't know of any obs guys running wastegate turbos even at crazy HP numbers. Maybe they do, I'm just not aware of it.

 

The turbine outlet flange is different (where what people call the "downpipe" is connected) so you'll have to mate a newer flange from the Superduty to the OBS pipe.

 

good point - though my current OBS DP is junk (not sure of the brand, it came wit the truck). its all over my tranny no matter how I adjust it.

so, it'll be getting scrapped when the new engine goes in, so i'll just replace it with an SD-compatible DP. it looks like most of them are 4", which won't fit past the OBS firewall, but a small body lift oughta make it work.

 

Ok guys - I have my engine torn down as far as I'm going to go and everything looks nice and clean inside. So, I've started pricing out the rebuild and based on costs so far, I am DEFINITELY going with the SD turbo that I already have.

That said, and since from what I read, removing an SD turbo is worlds easier than an OBS one, what do you all think of this plan: since the center bearing on my turbo seems to be ok, I'll just install it as is to see how the whole rig performs. Then, yank her back off for a rebuild or anti-surge mods if needbe... From what I read, it's just 4 band clamps and two bolts to get her off - nothing compared to the pedestal bolts and flange bolts to mess with on the obs.

As I see it, this plan is the lowest effort up front (quickest path to getting this engine in the truck), and I don't see much risk in the approach as long as I keep an eye on things after the install.

Thoughts?

Thanks!

 

The SD turbo is worlds easier to remove. Be sure and use anti-seize on the clamp to the collector since that is sometimes a pain to get off.

But the bottom line is, if you're going to run a chip on the SD turbo, and you're going to get your boost up much over 15 psi, you're going to get surge.

The only thing easier than removing a SD turbo is going ahead and installing the OBS wheel off your turbo in the SD turbo before you stick it on the truck.

(remember you'll should change the turbo to pedestal o-rings whenever you do pull the sd turbo)

 

Why not just rebuild your stock OBS turbo install a billet wheel on it, put on a 1.0 A/R exhaust housing, do your injector upgrades and T500 and call it a day for now? Then slowly collect parts for E-fuel and IC. I think a stock SD turbo and ped is a step backwards and a lot of extra cost for manifolds, up pipes, collector, intake y, plenums to reach 325-350 HP when you can do it with OBS gear that you have now.

jrc

 

Is surge a wastegate related thing? I'm sure someone would have tried this, but could you not just disable/block off the wastegate? Obviously that will lead to high boost numbers, which a stock PCM would not like (ok for me since I'll be run in a chip). I guess it could also damage the turbo itself in the long haul?

But yes, I can always do the obs wheel (which IS the wicked wheel,right?) on the SD turbo. I guess I'm just curious to see what it'll do on the truck as-is, though.

Thanks for the antiseize note, though. I put it on most engine parts, but prob wouldn't have thought to put it there!

 

It's kind of a long story, but I have to buy new manifolds anyway, and I with the engine out, I'm def doing bellows now. So, going with SD manifolds (which comes with the collector) and bellowed up pipes will actually save me a few hundred bucks. And as I see it, the SD pedestal will give me a few more turbo upgrade options once I have the dough. And, I do have the IC already, and will be doing E-fuel while the engine's on the stand. I am considering bucking up for the billet wheel (ww2?) for this sd turbo, though. With it as easy as it is - or so I hear and is confirmed here - I'll prob just run it stock for now and so the wheel sometime sooner or later. (Def sooner if I do get surge as 350 predicts). Again thanks for the info guys!

As for housings, the SD turbo I have has a .84 exhaust housing and 1.10 compressor housing. Wouldn't that be a much quicker spooling setup than the obs turbo (1.0+ exhaust, ~0.9 comp - I forget the exact numbers there).

 

Surge isn't a wastegate thing. It's compressor wheel stall, which is hard on the bushings in the turbo.

Yes the OBS wheel is the same thing as the wicked wheel. The other option would be a ported housing for a few hundred bucks.

 

Sorry - poorly worded question. Yes, turbo surge is compressor stall, but I had always thought it was stall due to loss of driving force from the exhaust turbine side. Which in turn is due to the waste gate offing off prematurely.

That is, the compressor wheel begins to stall due to excessive pressure in the intake manifolds. As it stalls, the exhaust back pressure between the exhaust turbine and manifolds shoots up, causing the wastegate to lift off, which in turn drops the exhaust manifold pressure greatly, slowing the turbine and this making the compressor stall worse. Once the intake manifold pressure decreases, the compressor wheel begins turning again, allowing exhaust pressure to drop, which allows the wastegate to close. Then, intake manifold pressure builds again and the cycle starts again - the cycling leading to the fluttering of the boost guage needle that is indicative of "surge"

So, I always thought that decreasing compressor efficiency (I.e, the downgrade to the obs wheel) is just one way to solve the problem. Better wastegate control would be another way... Except that a stock PCM throws a code/CEL above a certain boost level - pressumably to 'protect' the engine - head bolts, gasket, ect. However, with a tuner (and supporting mods), this shouldn't be an issue and making the wastegate stay closed longer/always should be ok.

Right? I'm def asking, not telling, but this has always been my [admittedly untested] logic.

 

Hey guys - its been a while since I've had time to work on 'truck stuff' - this weather in the North East has me on the tractor clearing the driveway every weekend all weekend, plus work's been a bear lately.

finally found a few minutes at lunch to look through and post some turbo pics I took a while back.

in short, could someone please confirm that the turbo on the left in these images is, indeed a stock SD turbo? (the one on the right is my stock OBS turbo for comparison)

I believe its a stock SD turbo I have, but it'd be nice to have a second opinion or two. I've translated the specs that I can read (can't make out the exhaust housing PN's or the OBS A/R clearly).

Thanks and hopefully I can find some time to spend on this project again soon!


compressor sides




exhaust sides




specs

 

By the pics and the specs you found, the one on the left looks to be a stock 99.5-03 turbo.

 

that was my thinking - thanks for the confirmation.

 

Yes you have two stockers there...the one on the left is the SD turbo. After reading through your thread I have a couple questions for you.

Regarding turbo: why stay at 2" plenums? If you have enough fab skills for up pipes and bellows, build your own plenums, or get a set of stockers off a SD. I had stockers off a SD with billet neck incerts from Riff Raff, and push well over 30 psi pre cooler when cranked up, on a stock OBS turbo and 160cc injectors. Never had an issue.

Seems to me this is just making more work for yourself, go up to a 3" setup and just get a factory 99+ if you want to use the SD turbo...they go for 25-50 shipped on ebay every day. Also. Yes aluminum billets are nice.. needed absoluteley not unless your pushing big pressure. I have built 7 or 8 sets of them now out of TIGd steel for for friends... maybe an hour or two and 5 bucks worth of steel. Def worth the time if you do it yourself.

For all the work you are doing and really want to make it worth it, I'd fab your own t4 setup and go with a 366 and call it a day, but that is me. It much more efficient than either of the stockers and is a super DD friendly turbo. Tows like a banshee as well.

pic of my first setup on a 6.0 cooler and stock turbo.

 

Nos - as you might have already guessed, the reason for the plan as is purely money. I have the engine on a stand right now, so I'm doing the stuff that would be a real pain to do once its back in, plus whatever else I can afford at this time.

that's really the only reason I am going with this turbo. as I understand, the s366 is not overly expensive, but considering the fact that I have to buy exhaust manifolds anyway, and the fact that this stock SD turbo is free, its hard to choose any other path at this point. plus with the SD turbo and pedestal, upgrading to a GTP38R should be a piece of cake later on (right?)

regarding plenums - I'm after taking some measurements, I find that the 2" plenums are only slightly restrictive compared to the 3" IC tubing that will be feeing them. 6.25 sq in in total area for the 2" plenums vs. 7 sq inches for the 3" IC tube. sure, upgrading would be better, but with the switch over to efuel, I see this as something not too difficult to do once the engine's back in - and I'm looking for truck work to do again :-)

I do plan to pressure test these plenums up to 30+ PSI, though. if any of the seals fail, i'll yank them and upgrade now.

all that said, I am having a tough time finding a spider to work with my stock SD turbo, 6.0 IC and stock OBS plenums. I'm quite sure something doesn't exist off the shelf, but I'm not opposed to a little fab.

it may well turn out that your modified SD plenums are the better way to go - thanks for the heads up!

and finally - that's a heck of a nice-looking OBS engine compartment!