champLSinteg

Last week I posted up because I just switched to a ramhorn with a 38mm gate and boost crept all the way to my boost cut at 17lbs. I switch from the 10lb spring to my 4lb and it still hit boost cut without the use of my boost controller. We came down to the conclusion that the gate was too small. I am now planning on buying a 44mm but I want to know if I should be fine with that.

Dunc

I just went through this a couple months ago with my car. I went from a log style with a 38 (no problems) to a ram horn and a 38 (major creep problems). I got the 44mm on there but didn't have any tubing so I used the 38mm style tubing for the dump. It still creeped bad. I swapped out the tubing, and bingo the problem was gone.

Conclusion: Yes the 44 will fix your problem, just makes sure to use the 44mm style tubing as well. This is assuming you didn't have problems with the last manifold.

SpoolnG2

I went through this as well a couple years ago. Full-race ramhorn manifold...t3 sc61..full 3" exhaust..built motor, etc. I had a 44mm wastegate with the proper dumptube and definately had wastegate creep. I had a 12psi spring in there and it would creep to 16-18psi. I even took the mani off and had the wastegate port polished and rounded out to help the airflow. That didnt even help. My advice as given in that other thread would be to go with a 60mm gate.

Schister66

In most cases, a 44mm wastegate will be enough, but it depends on the manifold design and the turbo you're using. Check this link and you might gain a little more insight as to what will work for you

http://www.evans-tuning.com/te....html

champLSinteg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">In most cases, a 44mm wastegate will be enough, but it depends on the manifold design and the turbo you're using. </TD></TR></TABLE>
This is what my set up is...


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote"> I had a 12psi spring in there and it would creep to 16-18psi. </TD></TR></TABLE> If mine would stay between 16 and 18 creeping from 12 I would just leave it. but mine is going from the spring of 5psi to hitting boost cut at 17 hard!

Schister66

The wastegate placement is good and by the looks of the turbo, i'd guess it to be a 60 trim. I dont think you'll have any issues with boost creep on that setup unless something crazy happens.

champLSinteg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">The wastegate placement is good and by the looks of the turbo, i'd guess it to be a 60 trim. I dont think you'll have any issues with boost creep on that setup unless something crazy happens. </TD></TR></TABLE> Yes it is a 60 trim! The funny thing is that I've seen quite a few setups with a ramhorn and same wastegate placement and using the 38mm. Could something have happened to the wastegate to not function correctly? I will give the 44mm a shot! Thanks Schister66, I see you posting here and always good input and advise!

SpoolnG2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">The wastegate placement is good and by the looks of the turbo, i'd guess it to be a 60 trim. I dont think you'll have any issues with boost creep on that setup unless something crazy happens. </TD></TR></TABLE>


How would you say that the wastegate placement is good?? Its at a 90 degree angle with no slant even to angle the air into it. Why would air want to come rushing down out of 4 separate pipes and make a 90 degree turn?? The thing is, it doesnt. The exhaust gas will travel the path of least resistance (into the turbo) which is why your getting your creep. Sure hope that 44 helps ya. But I can tell you from my experience that it sure didnt help me.

Schister66

take physics and learn how pressure works...you'll understand. If the wastegate was placed at an angle away from the engine, there would be a build up of pressure in the wastegate elbow causing it to open prematurely. The backpressure in the manifold is pressing equally on all sides meaning that even though the wastegate is 90* from the direction of flow it still sees the same pressure as the turbine.

champLSinteg

so basically whats happening is that my 38mm is opening but not relieving enough pressure to hold boost?

Dunc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">How would you say that the wastegate placement is good?? Its at a 90 degree angle with no slant even to angle the air into it. Why would air want to come rushing down out of 4 separate pipes and make a 90 degree turn?? The thing is, it doesnt. The exhaust gas will travel the path of least resistance (into the turbo) which is why your getting your creep. Sure hope that 44 helps ya. But I can tell you from my experience that it sure didnt help me. </TD></TR></TABLE>
It's not as life or death as you make it seem. My wastegate elbow has a slight uphill incline to it and it holds solid at all pressures. A straight 90 like he has will be plenty fine.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by champLSinteg &raquo;</TD></TR><TR><TD CLASS="quote">so basically whats happening is that my 38mm is opening but not relieving enough pressure to hold boost?</TD></TR></TABLE>
That is exactly correct.

SpoolnG2

If everything is so "fine and perfect" then why is he getting such bad creep?


Whats happening is that due to the placement of the wastegate, all the exhaust gas wants to go to the turbine (keep it spinning). The 38mm of opening isnt relieving enough pressure from the manifold which means that everything that is not exiting is going to your turbine and making it spin faster and faster (causing your boost creep). If you had a bigger wastegate it could let more of the exhaust gas out at one time which would not allow it to go to the turbo. Which is how you get rid of the boost creep. It has to do with not perfect wastegate placement so that the manifold is more efficient. People would rathter use a larger wastegate to keep boost levels stable down low rather then put the wastegate in an optimal place and let it rob the turbo of that extra air going to it.


Modified by SpoolnG2 at 11:40 AM 1/11/2008


Modified by SpoolnG2 at 11:42 AM 1/11/2008


Modified by SpoolnG2 at 11:43 AM 1/11/2008

SpoolnG2

Read this, it should hopefully help you.

https://honda-tech.com/zerothread?id=2174132

b20vtechb

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">Read this, it should hopefully help you.

https://honda-tech.com/zerothread?id=2174132</TD></TR></TABLE>


lol my brain hurt after reading that some people are just dumb

Dunc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">If everything is so "fine and perfect" then why is he getting such bad creep?


Whats happening is that due to the placement of the wastegate, all the exhaust gas wants to go to the turbine (keep it spinning). The 38mm of opening isnt relieving enough pressure from the manifold which means that everything that is not exiting is going to your turbine and making it spin faster and faster (causing your boost creep). If you had a bigger wastegate it could let more of the exhaust gas out at one time which would not allow it to go to the turbo. Which is how you get rid of the boost creep. It has to do with not perfect wastegate placement so that the manifold is more efficient. People would rathter use a larger wastegate to keep boost levels stable down low rather then put the wastegate in an optimal place and let it rob the turbo of that extra air going to it. </TD></TR></TABLE>

The two topics you are talking about are different. I agree that both can have an effect on creep (whether it being too small of a wastegate or a poorly placed wastegate outlet). However his current straight out the front design is very common. Judging by the image below and Full-Race's claims that their manifolds are designed for flow and wastegate placement...and their strong track record of functioning the right way time after time, I would say there is no issue with the "straight out the front design".

What people should also be asking themselves is <U>why</U> does Full-Race not provide their ramhorns flanged for 38mm gates. The answer is simply the 38 can not flow enough....it's not that the manifold is causing it and the bigger wastegate is a mere bandaid for the problem.

So the port placement is fine. The 38 is too small. The 44 will correct the problem (again assuming this issue started when the manifold was replaced and nothing else happened).

EDIT: Instead of spending all this time typing, how about this: original poster, go get a 44mm and put it on there. Make sure the outlet hole is opened up enough if need be, make sure to use 1.75" piping for the dump tube and see if that corrects your problem. I would honestly put a $100 bet down that it will and you won't need to proceed. Pretending that that does not work, then work with the wastegate placement on the manifold while still using the 44mm. Either way you need to have a bigger wastegate before you can solve the problem.

Once you have done that then come back here and let us know if just upgrading to the 44mm gate solved the issue. That will be the sure fire way of putting this debate to rest.

champLSinteg

The manifold is one of the older style that came flanged for a 46mm 4bolt gate. I already had my 38mm from my previous manifold and it held the boost fine so I just had a new flange welded on.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">Read this, it should hopefully help you.

https://honda-tech.com/zerothread?id=2174132</TD></TR></TABLE>
In this thread they talk about a 44mm and tony1 says that with a smaller turbo on any manifold there should not be any creeping issues. I consider my 60trim to be on the smaller side. Full-race do sell ramhorns flanged for a 44mm so that should be enough. I get that on there and update.

SpoolnG2

Just cause they sell them like that doesnt mean its always enough. In my case it wasnt. What stage wheel are you running in your 60 trim? What a/r's ?

atec

how are your Vacum lines routed??

Dunc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">Just cause they sell them like that doesnt mean its always enough. In my case it wasnt.</TD></TR></TABLE>

True I agree with that too. But a 60mm for 60trim is definitely overkill

building boost

i had the same style manifold with a similar sized turbo and a tial 38mm with dumptube. boost held rock solid at 14.7 psi all day.

Schister66

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">http://www.evans-tuning.com/te....html</TD></TR></TABLE>

Check this article and see what Evans has to say. Basically, a 38mm should be enough for most setups up to about 500whp depending on the manifold design and turbine size

SE-Rawkus

I'd look into the fact that it seems many people having these problems are running 2x+ what the wastegate springs are rated for. Something to look into; spring fatigue.

Skilz10179

What size is the turbine housing. A 38mm gate should be plenty assuming your turbine housing isn't too small.

champLSinteg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpoolnG2 &raquo;</TD></TR><TR><TD CLASS="quote">Just cause they sell them like that doesnt mean its always enough. In my case it wasnt. What stage wheel are you running in your 60 trim? What a/r's ?</TD></TR></TABLE>
I have the stage 3 wheel and .63ar.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by atec &raquo;</TD></TR><TR><TD CLASS="quote">how are your Vacum lines routed??</TD></TR></TABLE>
as of right now I just have one the bottom port of the gate hooked up to a source on my vacuum block.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SE-Rawkus &raquo;</TD></TR><TR><TD CLASS="quote">I'd look into the fact that it seems many people having these problems are running 2x+ what the wastegate springs are rated for. Something to look into; spring fatigue.
</TD></TR></TABLE>
I have two springs. I tuned with the 10psi spring and the boost controller to 15psi on the dyno. Now with the boost controller unhooked the 10psi spring and the 4psi spring creep to my boost cut at 17psi. I am sure i can boost alot more than 15psi with a 10psi spring though.

champLSinteg

I actually just got back from a track event that I went to with some buddy and I saw another ramhorn setup with the same gate placement and he was running the 38mm with a SC61 with the S housing. he said there were no problems with boost creep.