Waste Gated Turbo in a 1st gen?

[Racer Brown]

I've been reading a bunch of the posts on the smaller turbo housings that are available. My 93 has the 18cm2 housing and I noticed that many of you have changed to the 16cm2 housings. With what I know about turbochargers now and what I want from mine, I'm leaning more to the 14cm2 housing with a waste gate. Question is, what's involved in putting one of these on the 1st gen trucks. I also need to know what parts I'll have to change in the exhaust system to do this. TIA... ... ... ... . Racer

 

[KEENO]

Just a simple downpipe mod....

Hey Racer Brown!



The swap to the wastegated housings (14cm2 or 12cm2) is pretty straight forward! The only modification is that the 1. 25" to 1. 50" must be removed from the straight section behind the turbo mounting flange on the downpipe. This is because of the additional length of the wastegate set up.



The other option is to buy a completely new downpipe from Banks, Jardine, Stans Headers or others... $$$$



The mod is simple... Remove the pipe and have a quality muffler shop cut off the mounting flange . 25" behind the flange. Then, have them cut an additional 1. 25"-1. 50" out of the remaining straight section and re-weld the flange to the downpipe. The downpipe is complete.



Matt S just did his last week for a 12cm2 install! Maybe he can offer up a few tips!



KEENO

 

[Matt S]

I just put on the 12cm2. Made a big difference in responsiveness with only a 150* increase in temps. I'd do it again. I took the truck to a custom exhaust shop to fix the downpipe. I just can't seem to weld a pipe completely shut. I tried it without the modification to the pipe but it would touch the rubber mat on the firewall. I'm now working on getting my wastegate to stay shut. 28 psi isn't enough!

 

[KEENO]

HEY MATT!



What are your thoughts on "keeping the wastegate shut"?



Are you considering removing the 12cm2 once again and having the wastegate "flapper" tacked shut w/a welder utilizing nickel rod?



Just curious...



KEENO



You'll have to update that signature once again!

 

[JMorrow]

I thought there was a way you could adjust the 12cm2, I have one on my 1993 and there is I think an adjustment device of some kind. I Don't know how to adjust it.

 

[Lil' Dog]

All you guys need is a mini pressure regulator from a performance shop for Turbos. They aren't that expensive and you adjust it to open the 'gate at any set pressure. My buddy had a cheap one for his Supra, the other guy in the office has a digital one ($$$) for in the car control of his 400 Hp Stealth.



I definitely wouldn't weld it shut, too much back pressure in the manifold at full speed.



J-eh

 

[GOODE11]

Lil Dog, do you know if these regulators can be adjusted in the cab?



That would be awesome is you could adjust boost for pulling up to speed then when at the satisfactory speed, drop boost if not needed!

 

[Lil' Dog]

The digital one from HKS is in the cab of the Stealth, but it was about $400 Cdn. The manual adjusted type was much cheaper but you would have to pop the hood to adjust it. It goes in line with the pressure line from the turbo and the wastegate.



They may make a regulator for in the cab, I just haven't seen one other than the HKS.



J-eh

 

[Matt S]

I wasn't planning on taking it off the truck to weld it. Won't a regular wire feed welder do the trick? They didn't take my exhaust off the truck when they welded it.



As for the waste gate. Mine isn't hooked up. It just opens on its own. Not sure what that waste gate actuator would help a diesel. A weak gasser, yes.



I'm not concerned about how much boost there is. I'm confident the Cummins can handle what I put out. There are others with a lot more than I've got.

 

[KEENO]

Welding 101

Hey Matt!



My thought would be to just tack the wastegate "flpper valve" shaft external of the housing. Doing so with the actuator & pressure pod still attached would insure spring pressure on the flapper valve (closed position). After tacking the shaft the actuator assy could be removed & shelved. If needed, you could always grind off the weld and install a new shaft if an operation wastegate was needed... Remember that your welding dis-similar materials (Steel & Cast Iron).



I plan to install my completely 'plugged' & welded 12cm2 this weekend. You've inspired me to give it a try! It'll be interesting to compare notes...



KEENO

 

[Lil' Dog]

Originally posted by Matt S



As for the waste gate. Mine isn't hooked up. It just opens on its own. Not sure what that waste gate actuator would help a diesel. A weak gasser, yes.

If it opens on its own you would have to have about 50Psi exhaust back pressure pre-turbine. . Holy S#!T. Talk about lost horsepower!!! Not to mention abnormally high EGT's.

Wastegates make up for having an undersized turbine housing and allowing excess exhaust by. The wastegate has a purpose, to let the turbo do what it needs to without holding the engine back with unreal backpressure, as well as control boost pressure to what ever level is required.



I would just have it set to open at what ever boost you want, unless, you don't know what you want, that is.



If the wastegate is opening too early, hook it up to your intake manifold instead of right at the turbo. That would be good for the 2-3 Psi drop through the intercooler anyway. Plus it would allow for a regulator to be plumbed in.



My $0. 02



J-eh

 

[Jim Curry]

Hey Guys;



Another alternative is to buy a 12cm non-wastegated housing from High Tech Turbo. Only costs about $110. 00 plus shipping. No wastegate to weld shut and no downpipe mods to do. Just a drop in replacement like the 16 cm housing.

Just another alternative to think about.







Jim

 

[Matt S]

A non-wastegated 12? Never heard of it. Do they have a 14 cm2? Well, I guess I understand about the welding advice. I'm one of those guys who bought a welder but has never taken a class. I guess I need a class. 50 psi would be nice if I could get it to the intake side.

 

[KEENO]

Hey Jim Curry!



Do you have a tele# or website for High Tech Turbo?



A non-wastegated 12cm2 sounds interesting...



TIA... KEENO

 

[Jim Curry]

Hey Keeno; This is the address and phone number I have for High Tech. There website has changed and the only info up there is the address below. The phone number is off of my invoice from when I bought my 16 from them. I priced the 12 not to long ago at the 110. 00. Hope this helps you out.





Jim









HIGH TECH TURBO

4423 So. 500 W.

SLC, UT 84123

801-268-9721

 

[KEENO]

Heck of a find!

Hey Jim!



Great information & contact! I talked to "Paul" this morning over @ High Tech Turbo (801)268-9721 to confirm Price, Availability & Curiosity...



True Story:



HTT stocks & sells Non-Wastegated 12cm2 for $156. 40



They also sell wastegated 14cm2 for $407. 00. A Non-Wastegated 14cm2 is not available thru HTT.



Paul mentioned that these Non-Wastegated 12cm2 come from "across the pond" and are difficult to locate.



For those of you looking for a Non-Wastegated 16cm2... Piers has them on sale currently for $125. 00. Check PDR out @ www.piersdiesel.com



I wish I would of known about the Non-Wastegated 12cm2 before I had a used one welded up for experimentation. Maybe I'll just have to finally get around to installing it this weekend.



KEENO

 

[Racer Brown]

HOLD ON A MINUTE, QUESTION!

You can correct me if I'm wrong here but isn't the waste gate's function to allow excess exhaust to bypass the turbo? There has to be a point in the upper RPM range where there is more exhaust gas to pass than the 12cm2 housing will let go through, hence the waste gate. Given this, there is a point that even though boost goes up, horspower won't because of the excessive back pressure on the motor created by the welded up waste gate, which will also create too much heat! I'd say welding that thing shut is a mistake. Any other thoughts on this from the more experienced PPL in the group? Later, Racer

 

[Lil' Dog]

Racer

I already have beaten that horse here with no real answers. My comments are exactly as yours, I think that all this chase for higher boost with more restictive exhaust housings is a waste of time, not to mention HP... Any of the big HP guys toss the 14's for the 16, never mind a not gated 12... .



I can give the math for the lost hp from increased back pressure ie. turbo drive pressure if required. At full speed you may as well have a 2" exhaust system with it... .



MHO. ... J-eh

 

[KEENO]

Welded 12 installed....

Hey Jason & RB!



I installed my "experimental" welded 12cm2 over the weekend & will evaluate this week during normal driving.



I understand the purpose of the wastegate on the 12 & 14 housings & agree with the theories mentioned above & before. This is an activity to satisfy my own curiosity and not suck anyone else into my opinions. I've swapped the 12 & 14 back & forth several times now on my truck & the other First Gen has always had a 16cm2. So, I've got to play w/ all of them on almost identically prepared trucks...



Here's what I've found:



The "Welded 12" doesn't behave much differently than the wastegated 12 on my/our truck(s) (my opinion & experience). Yes, I does seem to loose a bit on the top end & I find this loss to be in line with what the wastegated 12 exhibited. The low end & mid-range reponsiveness is impressive though & the EGT are up maybe 100 degrees... Same as wastegated 12. The Boost differences between the welded & wastegated 12 are exactly the same to my disappointment. I'm getting 28# in 4th & 30# in 5th... Same/Same! I was getting a max of 26# w/ the 14cm2 I just took off when the wastegate opened (for reference).



Much of this was done to prove to myself that w/ the limited fueling of the Bosch VE44 on our First Gens that a wastegate isn't as necessary as on potentially over fueled P7100 & VP44 brothers. Remember D/C is putting 9cm2 & 10cm2 on the newer 24 valved trucks that have incredible fueling capacity over our trucks. I'm a bit disappointed that the "Tale of two 12's" has such a identical ending to the story!



I plan to drive this housing for a few weeks and evaluate... In the end I might just put the 14cm2 back on my truck and leave it! The only remaining question would be to 'tack' the flapper valve shut or not?



Just KEENO's weekend fun!



How was your weekend Matt S?

 

[Lil' Dog]

Interesting results. . But some of it is expected if you have a wastegated housing with the actuator line plugged. The spring on the gate will keep it closed far above your spec'd exhaust pressures.



The tacking of the actuator is not required, as you have proven, with the 14 if you have unhooked the actuator or you have a regulator set above the boost the manifold. Basically you have "tacked" the gate by unhooking the line to the actuator.



Good research.



J-eh