Here is some feedback reguarding the Q trim wheel that I did. Im running a 3 bolt 72 with a P trim wheel and a Garrett .82 exh housing.. I'm using a TH DP with the intergral wastegate. 1.5" puck. I have the high pressure actuator. I couldnt get more than 24 psi. In talking to John C I thought maybe I was running out of turbo. He told me to wire the wastegate door shut to see if I could make more boost. I had already tightened the rod as far as it would go. After tying it shut with bailing wire and going around it 3 times I took it for a run. The boost went to 26 psi. When i got back and looked under the hood the wire had stretched and the door got pushed open!!!. I though damm I have some serious BP in there. I told John and asked if I should step up to the Q trim. He said to try 1 more thing,a Precision .85 first. I did and nothing changed. So he came to the conclusion that I had reached the choke point of the P trim wheel. He estimates thatI have over 50 psi BP in the housing for that to happen. I have since gone to a Q trim to try and am wating for a day to do it.
Header leak causing HIGH egt's???
- Thread starter Spooled
- Start date
TurboTR, the goal is LOW 10s, i'm running high 10s now on 12 lbs.
JDE, those pressure numbers were with the intercooler installed. I'm going right now to make some passes with a pressure guage before and after the intercooler.
Someone is suppose to be sending me a 1.12 turbine housing for me to try with my p trim wheel. If that doesn't work, I guess I'll have to sell this T72 and buy the 74 q trim.
I'll let ya know how the pressure drop goes across teh powerstroke intercooler. Thanks guys!@
JDE, those pressure numbers were with the intercooler installed. I'm going right now to make some passes with a pressure guage before and after the intercooler.
Someone is suppose to be sending me a 1.12 turbine housing for me to try with my p trim wheel. If that doesn't work, I guess I'll have to sell this T72 and buy the 74 q trim.
I'll let ya know how the pressure drop goes across teh powerstroke intercooler. Thanks guys!@
Have I found my problem???
Ok fellas, here's what I found today. I put my boost guage right on the compressor housing. I have a 1/8 pipe fitting about 5 inches behind the outlet of the compressor housing that I tapped into. I then hooked everything up as normal. I was going to log a run, and watch the boost guage and compare the boost pressures. WOW! I had my blitz boost controller set on 45, which usually yields 19 lbs in the intake. I get into the throttle and bam, peg's the guage at 20, so i let out fast. I did this at different settings till I finally go down to 10. This usually yeilds 11 lbs at the intake. So i rip on it...I am seeing about 18-19 lbs on the boost guage (remember it's connected tot he compressor housing), and when i get back, I checked the log and was seeing about 11-11.5 at the intake. So i've got one hell of a pressure drop. Image what the boost is at the compressor housing at 19 lbs at the intake! But one question, since I measured the boost on teh compressor housing way back there where the area is very small, would it be any different than measuring it in the plenum of the intake? COuld that be some of my drop? If not, then i'm thinking the intercooler's the problem and not the turbo. ALso, on those runs, when i saw 11 at the intake, i had about 30 psi in the exhaust before the turbo. And on the "45" setting on the blitz controller, i had like 55. So i'm thinking when i try and get 19 in the intake the turbo is working MUCH too hard and it's puttin out like 32 lbs of boost and that's causing the HIGH EGTs, alog with the decrease in power. I also learned that VE's are slightly HIGHER at 11 lbs than they are at 18 lbs boost. So am i getting into the surge part of the compressor map maybe? To add to the problem as well, i have about 3 tubes on the top of that intercooler that are crushed in. The front of my car bumped into the workbench 4x4 post and crushed a few tubes in. So i'm sure that's not helping flow any. Think it's time for a new intercooler?
Ok fellas, here's what I found today. I put my boost guage right on the compressor housing. I have a 1/8 pipe fitting about 5 inches behind the outlet of the compressor housing that I tapped into. I then hooked everything up as normal. I was going to log a run, and watch the boost guage and compare the boost pressures. WOW! I had my blitz boost controller set on 45, which usually yields 19 lbs in the intake. I get into the throttle and bam, peg's the guage at 20, so i let out fast. I did this at different settings till I finally go down to 10. This usually yeilds 11 lbs at the intake. So i rip on it...I am seeing about 18-19 lbs on the boost guage (remember it's connected tot he compressor housing), and when i get back, I checked the log and was seeing about 11-11.5 at the intake. So i've got one hell of a pressure drop. Image what the boost is at the compressor housing at 19 lbs at the intake! But one question, since I measured the boost on teh compressor housing way back there where the area is very small, would it be any different than measuring it in the plenum of the intake? COuld that be some of my drop? If not, then i'm thinking the intercooler's the problem and not the turbo. ALso, on those runs, when i saw 11 at the intake, i had about 30 psi in the exhaust before the turbo. And on the "45" setting on the blitz controller, i had like 55. So i'm thinking when i try and get 19 in the intake the turbo is working MUCH too hard and it's puttin out like 32 lbs of boost and that's causing the HIGH EGTs, alog with the decrease in power. I also learned that VE's are slightly HIGHER at 11 lbs than they are at 18 lbs boost. So am i getting into the surge part of the compressor map maybe? To add to the problem as well, i have about 3 tubes on the top of that intercooler that are crushed in. The front of my car bumped into the workbench 4x4 post and crushed a few tubes in. So i'm sure that's not helping flow any. Think it's time for a new intercooler?
Spooled - it does sound like you are learning a lot of good things here!
That intercooler sounds like it is definitely a problem. You could try taking the IC out and going for another run. If your ratio of exhaust pressure to MAP pressure drops down from it's current 30/11.5=2.6 to something below 2.0, preferably in the 1.5ish range I think, then you will really know that you are on the right track. I think if you run it at 19 psi without the IC, you should see about the same 30 psi backpressure.
As for the VE change, the worse the backpressure is the more exhaust gets left in the cylinder, and the less fresh charge can get in, and this is expressed as a lower VE. So it's not surprising that the lower backpressure level helped the VE out a little. I think you'll see the VE's get better if take the IC off, and you ought to see them get better when you replace the IC with a lower pressure drop unit.
John
That intercooler sounds like it is definitely a problem. You could try taking the IC out and going for another run. If your ratio of exhaust pressure to MAP pressure drops down from it's current 30/11.5=2.6 to something below 2.0, preferably in the 1.5ish range I think, then you will really know that you are on the right track. I think if you run it at 19 psi without the IC, you should see about the same 30 psi backpressure.
As for the VE change, the worse the backpressure is the more exhaust gets left in the cylinder, and the less fresh charge can get in, and this is expressed as a lower VE. So it's not surprising that the lower backpressure level helped the VE out a little. I think you'll see the VE's get better if take the IC off, and you ought to see them get better when you replace the IC with a lower pressure drop unit.
John
John, about a week ago, I took the intercooler out and just looked for a +correction of the 02 sensor. It was minor. I might do it again and mesure the pressure ratio as you suggest. i thought about doing it today but it's kind of a pain to take it out and rig up the piping so I didn't do it. I'll try it in the next coupla days and let ya knwo what happens. Tests....tests...and more tests... 
oh yeah, if you do go intercooler shopping, look for something that can flow about 750 cfm @ 1 psi drop (~28" water) or so through the tubes. That should present a lot less restriction than what you apparently have now. You could put your existing IC on a flow bench and see how it compares to the above if you're curious.
John
John
The restriction has to be somewhere between the compressor housing and the location of the MAP sensor. I presume the MAP sensor is connected to the intake in some manner? If so I guess a rag or a dead rat in the throttle body or piping could do it... The stuff they find in refinery piping and equipment is amazing. Hard hats, rain coats, lunch boxes, note books, styrofoam coffee cups, all do a great job at plugging stuff up! Why the **** they don't think about cleaning that stuff out before they bolt it back together I'll never know. Anyway, taking the IC out and looking at the difference between discharge pressure at the compressor housing and MAP would positively confirm it.
John
John
Well today i put my intercooler bypass hose on. I saw about 16 lbs at the compressor and about 14.5 at the intake. I said earlier that my compressor fitting was about 5" behind the outlet..well thats' wrong. It's WAY behind the compressor outlet. It's about 270 degrees from the compressor outlet. It's down in there where the compressor ID is very small. I don't know if that's indicating a little more pressure there b/c the area is so small but it's just a thought. I definitely think alot of the problem is the intercooler now. I didn't get a chance to see the exhuast pressure b/c my bypass hose blew off. I cut off the 4 bent rows of the powerstroke intercooler...and cut my finger so bad in doing so I shoulda got stitches Anyways, i'm gonna patch up the end tanks and try it that way. I'm HOPING to get it done by this weekend and head up to the track saturday night for my first 10 sec timeslip! I'll get some more pressure results after this intercooler is patched up.
Anyways, i'm gonna patch up the end tanks and try it that way. I'm HOPING to get it done by this weekend and head up to the track saturday night for my first 10 sec timeslip! I'll get some more pressure results after this intercooler is patched up.I thought you were already running high tens though? I don't see how removing several (crushed even) rows is going to help the pressure drop? I hope it does, but you'll be reducing the cross sectional area and that should hurt pressure drop, not help it (?) Iguess we'll see. Hopefuylly it goes faster at least. Who knows, at 11 psi boost maybe you'd get more speed non-intercooled even I had a friend with a blown Cobra that went faster with a few more psi boost and no IC vs the IC and a few psi less boost.
TurboTR
I had a friend with a blown Cobra that went faster with a few more psi boost and no IC vs the IC and a few psi less boost.TurboTR
Well, last time i went to the track, it was the hottest day of the year and a huge head wind and i had a few 11.20 passes at 124, and everyone there (the big bracket racers) were running almost exactly .5 off their normal times. So i figure it's got easy high 10s. As far as the core goes, it's HUGE. I'm sure you've seen one. They are 30x18x2. I took about 6 inches off of the top. Those four rows were completely smashed down and the air was rushing into them and it was like hitting a wall. Probably trying to back up and caused turbulence and pressure drop. I wouldnt' think it could hurt anything. The end tanks are VERY small on these http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1853065904
There isn't much area for the air to travel in. I'm just going to try it like this and see what happens. If it doens't work, i guess i'll have to get a good core/intercooler. If I can't find one in time before the season ends, i'll take a trip to the track non-intercooled. I, myself, thought this "fixing" of the intercooler might help alot. Were you just misunderstanding what I was doin or do you still think it would cause MORE of a pressure drop?
There isn't much area for the air to travel in. I'm just going to try it like this and see what happens. If it doens't work, i guess i'll have to get a good core/intercooler. If I can't find one in time before the season ends, i'll take a trip to the track non-intercooled. I, myself, thought this "fixing" of the intercooler might help alot. Were you just misunderstanding what I was doin or do you still think it would cause MORE of a pressure drop?
Man those end tanks are small! If you can give me the dimensions of the tubes (inside height and width) and the # of tubes I can make a stab at the pressure drop. Just an estimate you understand, but it should tell us whether the restriction is in the tubes or the end tanks. Whatever the case, since taking the IC out improved the difference between your two pressure measurement points by a good 6 psi, I think it's safe to say that something about the IC is a problem.
As for the location of the compressor discharge pressure measurement point, from what it sounds like I don't think you have the most accurate spot. I'd rather see something right at the outlet. But, since we're really looking at differences instead of absolute numbers, I wouldn't worry about it. Bummer you didn't get a chance to read the exhaust backpressure... Does it feel a lot more responsive without the IC in place? Turbo lag get better?
John
As for the location of the compressor discharge pressure measurement point, from what it sounds like I don't think you have the most accurate spot. I'd rather see something right at the outlet. But, since we're really looking at differences instead of absolute numbers, I wouldn't worry about it. Bummer you didn't get a chance to read the exhaust backpressure... Does it feel a lot more responsive without the IC in place? Turbo lag get better?
John
John, i cut out the rows of the intercooler that were bent up and patched it up. I loaded the car on the trailer to take to teh track. Iheard a knockign noise so i unload it and drain oil. I've got alot of metal in the pan! I'm taking the motor out in the morning to see what the hell went wrong. I was really looking forward to seeing if that patching of the cooler worked. But now i've got other problems to deal with. Hopefully it's not too awful bad and i can get it back to the track before this year's over. I'd like to talk to you about intercoolers sometime. I'll drop you an email this week. thanks for the help!
nightdiver
New Member
- Joined
- Feb 25, 2002
Spooled
Ha
same here,i did one piston
I saw the cooler you got and i see that it has very little flow
I have a Kenne Bell a2a that is 18 inches x 3,5 that makes 63 sq.inches and does for 500 to 600 hp
Your cooler has just 36 sq.in. wich is nothing for your set up
I am ready to order a bigger one 23 x4 =92 sq.in. flow area
Now this is what i call flow without pressure drop
Your end tanks are small for sure but making those bigger aint gonna cure your problem
Regards from sunny Greece
Ha
same here,i did one piston
I saw the cooler you got and i see that it has very little flow
I have a Kenne Bell a2a that is 18 inches x 3,5 that makes 63 sq.inches and does for 500 to 600 hp
Your cooler has just 36 sq.in. wich is nothing for your set up
I am ready to order a bigger one 23 x4 =92 sq.in. flow area
Now this is what i call flow without pressure drop
Your end tanks are small for sure but making those bigger aint gonna cure your problem
Regards from sunny Greece
