Denmah kit - GT45 Help
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Denmah kit - GT45 Help Hey everyone,
I posted this in my build thread (link in sig) but I figured it would have a better chance of being answered here.
I am having a problem with this turbo burning oil. It's a regular cheap GT45 you get with the Denmah kit. At first I thought it was possibly a feed/drain problem. Maybe it still is. What do you guys think?
Feed: 4AN coming from directly above the oil filter. Has a .060 restrictor in the line.
Drain: 1/2" falling directly down (maybe 2') to the timing cover. I originally had a 90 degree fitting in there which I have heard can cause problems. However, I removed it and it still does it.
The car does have high oil pressure ~55psi at idle. Goes to 80 at higher RPMs.
Driving the car around without getting into boost there are no problems. As soon as I step on the gas a little (not even getting into boost, but so you can hear the turbo start to spool) it blows a small amount of blue smoke. If I really get on it, it smokes. Then if I let off it blows a huge cloud.
I haven't tested to see if it could be valve seals or something. I am fairly certain it is the turbo because I took off the intake tube and there was a pool of oil in it. I also removed the center section from the exhaust housing and there was baked on oil.
It just seems weird, I thought for sure it was my drain. But, it flows fine and we even put an adjustable valve in the feed to further limit the oil the turbo is getting. We cut it down to half (approx. 150ml/20secs, was 275ml/20secs before - at idle) and it made no difference.
Did I get a bad turbo? Or could I possibly be still getting too much oil to the turbo/not enough away?
Any help is appreciated!
I posted this in my build thread (link in sig) but I figured it would have a better chance of being answered here.
I am having a problem with this turbo burning oil. It's a regular cheap GT45 you get with the Denmah kit. At first I thought it was possibly a feed/drain problem. Maybe it still is. What do you guys think?
Feed: 4AN coming from directly above the oil filter. Has a .060 restrictor in the line.
Drain: 1/2" falling directly down (maybe 2') to the timing cover. I originally had a 90 degree fitting in there which I have heard can cause problems. However, I removed it and it still does it.
The car does have high oil pressure ~55psi at idle. Goes to 80 at higher RPMs.
Driving the car around without getting into boost there are no problems. As soon as I step on the gas a little (not even getting into boost, but so you can hear the turbo start to spool) it blows a small amount of blue smoke. If I really get on it, it smokes. Then if I let off it blows a huge cloud.
I haven't tested to see if it could be valve seals or something. I am fairly certain it is the turbo because I took off the intake tube and there was a pool of oil in it. I also removed the center section from the exhaust housing and there was baked on oil.
It just seems weird, I thought for sure it was my drain. But, it flows fine and we even put an adjustable valve in the feed to further limit the oil the turbo is getting. We cut it down to half (approx. 150ml/20secs, was 275ml/20secs before - at idle) and it made no difference.
Did I get a bad turbo? Or could I possibly be still getting too much oil to the turbo/not enough away?
Any help is appreciated!
oil feed at the top and oil drain at the bottom of the turbo?
sorry i had to ask, we have seen people with turbo feed and drain horizontal haha
see if your drain is clogged
i have seen it happen many times
sorry i had to ask, we have seen people with turbo feed and drain horizontal haha
see if your drain is clogged
i have seen it happen many times
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Haha no worries. Yes, I have the turbo clocked so that the oil drain is perpendicular to the ground. Draining straight down. Has a fall of probably 16 inches and an overall run of maybe 28 inches. I have had the hose off and it flows tonnes of oil. I also stuck my finger into the hole on the timing cover. I couldn't feel any obstruction there. The .060 restrictor that they send with the kit is what I am using. Plus the adjustable valve now. Doesn't seem to make a difference.
I am going to run the car with the intake off and see if it smokes as badly. If it does the next step I guess is to remove the turbo completely and see if it still smokes.
I read a couple things online about rebuilding these turbos with better seals and such, have you ever had to do that? Any luck with it?
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
I took a couple of pics.
Let me know if anyone sees anything wrong!
I had AN line and a 90 degree fitting at the timing cover before but I removed that to see if the 90 was causing the problem. Right now It's sloppy-style with a ID 1/2" fuel hose. Looks pretty direct to me, I'm no expert though.
My only other thought is that maybe the motor has too much oil pressure? Obviously 55psi is quite a bit, my old small block had ~30psi at idle.
Let me know if anyone sees anything wrong!
I had AN line and a 90 degree fitting at the timing cover before but I removed that to see if the 90 was causing the problem. Right now It's sloppy-style with a ID 1/2" fuel hose. Looks pretty direct to me, I'm no expert though.
My only other thought is that maybe the motor has too much oil pressure? Obviously 55psi is quite a bit, my old small block had ~30psi at idle.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Okay, sorry for all of the posts. I took the intake side completely off the turbo compressor and went for a drive. The car is no longer smoking at all. I opened the hood and the turbo had blown oil all over my engine and there was an actual pool of oil in the coupler that was hanging off the turbo outlet. Needless to say, it is definitely the compressor side of the turbo that is leaking oil. I am running it without an air filter at the moment (haven't mocked one up yet) and I don't have a blow off valve. Would either of these cause it to leak oil like crazy??
I guess the next step is to take the turbo apart and inspect the seals.
I guess the next step is to take the turbo apart and inspect the seals.
Okay, sorry for all of the posts. I took the intake side completely off the turbo compressor and went for a drive. The car is no longer smoking at all. I opened the hood and the turbo had blown oil all over my engine and there was an actual pool of oil in the coupler that was hanging off the turbo outlet. Needless to say, it is definitely the compressor side of the turbo that is leaking oil. I am running it without an air filter at the moment (haven't mocked one up yet) and I don't have a blow off valve. Would either of these cause it to leak oil like crazy??
I guess the next step is to take the turbo apart and inspect the seals.
I guess the next step is to take the turbo apart and inspect the seals.
Trending Topics
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Yes I am!
I'm thinking about ordering an S475 with the T4 flange. How are the external dimensions of that compared to the GT45? I'm hoping to not have to change the piping too much.
I am going to take this GT45 apart and have it looked at by my turbo guy. I'm thinking I might have just got a bad one.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Alright guys,
Sadly I think I got a bad turbo. I played around with it all afternoon, I have an adjustable valve on the feed line so I was able to vary the amount of oil the turbo sees. I am getting oil in the compressor no matter how much oil the turbo is getting. I turned it down to about 1/5th the amount it was getting with just the .060 restrictor, it still burns oil. Albeit, less.
After we couldn't get it to work I took it to my turbo guy and he says that the design of the seals on the compressor side is something he normally sees in diesel turbos. Not sure if this is a bad thing or not, apparently he thinks it should have a spring loaded ceramic seal instead of just the piston ring type seal.
I gambled and lost apparently! Although I had a lot of fun doing it, the turbo made 10psi no problem, just burned oil. I'm going to order an S475 with the T4 housing and see how that goes!
Thanks for your help everyone.
Sadly I think I got a bad turbo. I played around with it all afternoon, I have an adjustable valve on the feed line so I was able to vary the amount of oil the turbo sees. I am getting oil in the compressor no matter how much oil the turbo is getting. I turned it down to about 1/5th the amount it was getting with just the .060 restrictor, it still burns oil. Albeit, less.
After we couldn't get it to work I took it to my turbo guy and he says that the design of the seals on the compressor side is something he normally sees in diesel turbos. Not sure if this is a bad thing or not, apparently he thinks it should have a spring loaded ceramic seal instead of just the piston ring type seal.
I gambled and lost apparently! Although I had a lot of fun doing it, the turbo made 10psi no problem, just burned oil. I'm going to order an S475 with the T4 housing and see how that goes!
Thanks for your help everyone.
What is your catch can setup for crank case pressure? I pulled my catch can off while doing some fab work and put AN caps on my valve covers, started the car it it pushed lots of oil past the rings as the crank case couldn't breathe.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
I don't really have one at the moment. I thought the same thing as you so I just stuck a rubber hose on the valve cover and "vented" it under the car. I think I am probably going to buy the mightymouse one. This should work okay for the time being though. I was able to confirm that the engine doesn't smoke at all (yay) it was just the turbo.
I called Forced Inductions up today and ordered the S475 with a 1.25AR T4 housing. Hopefully it isn't much bigger than the GT45, I would rather not change my hotside piping.
I called Forced Inductions up today and ordered the S475 with a 1.25AR T4 housing. Hopefully it isn't much bigger than the GT45, I would rather not change my hotside piping.
Last edited by LSChevelle; Apr 25, 2014 at 12:33 PM.
i never run a blow off valve and have built a ton of turbo kits with these turbos, without an issue.
not sure what the deal is here, maybe talk to VS and see if he has some suggestions or will swap it out?
not sure what the deal is here, maybe talk to VS and see if he has some suggestions or will swap it out?
Staging Lane
Joined: Aug 2013
Posts: 98
Likes: 0
hose kinda looks kinked ?
add make your drain better before deciding turbo is bad. you can add like 4 inch of vertical drop by moving fitting to pan, up size to 10an, also seen where people add a little reservoir below turbo when they have long horizontal stretches
add make your drain better before deciding turbo is bad. you can add like 4 inch of vertical drop by moving fitting to pan, up size to 10an, also seen where people add a little reservoir below turbo when they have long horizontal stretches
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
It threads into there approx. 1/8th of an inch. I stuck my finger in there and couldn't feel anything, which makes me think it should have enough flow. I never thought, I should have used the calipers to see how far away the block actually is, I'll check that today.
I had an adjustable valve on the feed line and restricted it down a lot and it still leaked oil past the seals, it is 100% possible that I over-oiled the turbo at the beginning. But, most guys say that over-oiling it usually doesn't wreck the seals.
Yea, good eye. It was kinked a bit, that is why we put the hose clamp on to keep it round. I would have tried moving it to the pan. I have an aluminum pan (and no TIG) and can't take the pan off with the engine in the car though. So it would have been a lot of work to get it out and then I would have to pay someone to TIG a fitting on there. It may come to that still. If it wasn't for the fact that limiting the oil supply down (which in theory should have also limited down the amount going into the drain) didn't affect the turbo burning oil, I would have tried this.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Hey all,
I thought I would update this. I have been working with the guys from VS Racing to try and figure out what is up with this thing! They requested that I do a leak-down test on the engine because they were convinced I must have huge crank case pressure as a result of excessive blow by. Fortunately for me, the test came back amazing, less than 8% leakdown on all the cylinders (1-2% on 6 of them.) VS Racing has agreed to take the turbo back and send me a replacement. I can't say enough good things about the service and prompt email replies I have received. I will update once I get the new turbo back and hopefully it doesn't burn oil!!
I thought I would update this. I have been working with the guys from VS Racing to try and figure out what is up with this thing! They requested that I do a leak-down test on the engine because they were convinced I must have huge crank case pressure as a result of excessive blow by. Fortunately for me, the test came back amazing, less than 8% leakdown on all the cylinders (1-2% on 6 of them.) VS Racing has agreed to take the turbo back and send me a replacement. I can't say enough good things about the service and prompt email replies I have received. I will update once I get the new turbo back and hopefully it doesn't burn oil!!
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 97
Likes: 0
Hey guys,
I just thought I would update this with the results! I received the replacement turbo on Friday and got it bolted up. I didnt change anything. This one doesn't burn any oil!! It also feels like it spools a lot faster and isn't as noisy. Glad I got this figured out, it was driving me nuts!
Thanks again to VR Speed for going the extra length to make the customer happy!
I just thought I would update this with the results! I received the replacement turbo on Friday and got it bolted up. I didnt change anything. This one doesn't burn any oil!! It also feels like it spools a lot faster and isn't as noisy. Glad I got this figured out, it was driving me nuts!
Thanks again to VR Speed for going the extra length to make the customer happy!
