Boost Creep Problem after 2 changes

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Well, I went and REMOVED the dump line from the downpipe, sealed off the hole at the downpipe, and now im running OPEN dump and its holding SOLID at 8 psi..!!Its very loud, which I HATE, but at least my boost is holding now..Thank God..!!!So now i have to order a 1.5 inch mandrel bent pipe to shoot the dump down and then re-route it back somewhere at the mid-pipe and bring it in at an angle... And hope that works..OR Buy a small muffler that will absorb MOST of that noise..!!

Website · Post by **daniel240** » Sat Feb 07, 2004 1:58 pm

i think it would be a lot simper to use a small muffler. and believe me it really works, i could barely here when my wastegate opened up when i had a small muffler on mine. i was just using a small muffler i bought at an auto parts store for $5.

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Well how "small" of a muffler are we talking about..?? Is this a chambered muffler that will restrict the wastegate flow by any chance..?? Or is it a straight thru design or what was this muffler made for..??I dont mind a little bit of wastegate dump noise, but not what i have now..!!

Website · Post by **daniel240** » Sat Feb 07, 2004 1:58 pm

i think its for small engines. its not straight through. id say its about 10'' long cylinder shape.

Post by **SloS13** » Sat Feb 07, 2004 1:58 pm

I got a muffler on my dump tube and LOVE IT. I would take it off at night and sleep with it if I could. ~$5 at Advance Autoparts in the small motors section. You can still hear a sound change when the wastegate opens, but it sounds 100000x better than open dump tube.

Its about 6-8" long and roughly the diameter of a coke can..no...pepsi can.

Post by **j-z** » Sat Feb 07, 2004 1:58 pm

awesome, i may try that first before i reroute into my dp. it would be alot easier to do it that way. also how does your iap mani differ from your rev hard mani? can you tell of any differences?

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

HMMDifference between the revhard and IAP manifold.. HUGE..!!The Revhard worked, but the design of it was not made for all out hp...Revhard: Spool up started at about 3k rpm...At top rpm and/or high speed the motor was choking. Passing 5k rpm the motor felt like it was dying. At top speed (4th gear) the same problem, it just felt like there was no pwer left.

IAP manifold: Spool up started at about ~1700 rpm NO LIE.. This motor reved to redline with EASE..!! I sware if this motor could run to 9k rpm, it would go..!!I could just feel the motor PULLING to redline with ZERO hesitation, too bad I have to shift at 6k rpm.. And also top end speed is incredible, it just goes and goes..

This manifold was WELL worth the money. Dont get me wrong, the revhard did its job, it worked fine, but it was not designed for all out power. I got rid of it cause im building up a spare KA with all new internals, and will be pushing about 600+ rwhp and the revhard just isnt gonna cut it..

Now I just have to find a way to quiet down this annoying dump..

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Boost Creep is BACK..!!!Why its back, I can tell u why. I went and purchased a 1 inch 90 degree mandrel bent pipe and had it welded to the dump flange on my wastegate. So now i have the dump dumping down to the ground.. But for some reason now my boost creep is back. Could it be the pipe being too small or is it the 90 degree turn down..??I should not have any restriction in the wastegate flow anymore..The hole on the dump flange is 1.25 inch in diameter, but i was only able to find a 1 inch mandrel bent 90 here locally so i went with that one...But I know for a fact that i can fit a 1.5 inch pipe on that dump flange.. I just have to order one on-line.I removed the dump pipe completly and the boost held solid, so its either the pipe too small or that 90 degree bend down..Im not too sure which it is..

ThanksRobert

Website · Post by **TurboKA37** » Sat Feb 07, 2004 1:58 pm

probly a combination of both. id try out the 1.5" one to see if that helps

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Well, Im gonna order the 1.5 inch 90 from JC whitney and try it again to see what happens....

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Ok guys, about my wastegate dump return.I got under the car and saw a spot where I think it may work.From the turbo i have the downpipe which drops down the firewall and attaches to the Mid-pipe ( http://www.projectnissan.com/p...e.jpg )On this midpipe I have a 90 degree bend as u can see from the picture. Can i dump the wastegate back in thru that 90 degree turn..?? Or should i just go further down the pipe and come in at a 30 degree angle..??

Do u think that route would work...??

Post by **TrunkMonkey** » Sat Feb 07, 2004 1:58 pm

the further down the exhaust the better.

-demetrius

Post by **huguetpj** » Sat Feb 07, 2004 1:58 pm

I don't see any 90° bend on the downpipe in the picture... but anyway... it is best to merge the wg return and downpipe at a 45° angle or less. You might have boost creep if you merge them with a higher angle.

Post by **C-Kwik** » Sat Feb 07, 2004 1:58 pm

I have mine routed back in at a similar point. It's naturally a good place for it if you have the pipe merging to the pipe parallel to the ground right where the bend is. It's also pretty far from the turbo so it should have minimal effect if any on the gasses exiting the turbine.

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Ok, guys, i inserted a hand drawn picture of what i meant. It kinda came out sideways and not large enough. But try to make it out. Basically I wana route the dump return line to enter the mid-pipe at that sorta 90 degree turn...If that doesnt work, then i can always enter it further down the ex stream at about 30 degree's...OH by the way the picture is above at that post where i gave u that link to the picture of that mid-pipe i have..

Post by **TrunkMonkey** » Sat Feb 07, 2004 1:58 pm

that will work. i'm sure that's what c-kwik was talking about.

-demetrius

Post by **Projex240** » Sat Feb 07, 2004 1:58 pm

OK great----glad we all got that cleared up. After the pee pee contest, i thought wed never get it staright.

RN240sx--you should really think about getting the dump opened up. Ive heard, but cat say for sure without dyno sheets, that you actually gain power form running open dump.

If you dont liek the sound of the open dump--got a small tractor "muff" (me and wd were laughing about that) from a lawn mower shop, home depot, etc--it doesnt sound bad at all--acutally sounds really screamy and intimidating without the ricey sound that is sometimes associated with open dumps.

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Well, if i can find a SMALL TINY muffler to fit down and IF it quiets it down to a descent level, then i might consider it.But as it is now, its loud and annoying, and everyone here locally loves that sound and they compliment me on it all the time. Not that i mind the compliments, cause I do, but i still have that sound...Not sure about you guys that love that open dump sound, but me I prefer the sound of a turbo spooling up to redline..!! If anyone has a site on where I can visually see these tiny mufflers, let me know. I have been to local speed shops, and a few automotive shops and all they have are the large flowmaster, maxspeed, borla, etc type mufflers..Maybe im looking into the wrong places...

And i also heard that the open dump does add more hp simply cause its kept away from the turbine's exhaust path and lets it spin freely without any interuptions. Im all for that, but its just way too loud and i need it to quiet it up a LOT...

Post by **huguetpj** » Sat Feb 07, 2004 1:58 pm

I think somebody said Autozone... maybe look in motorcycle parts shops or something. Cause normally a car won't use a tiny muffler like that.

Post by **rn240sx** » Sat Feb 07, 2004 1:58 pm

Ivoryj30t Wrote:no, its not the return that the problem, its that the flow of the exhaust is causing a restriction to the wastegate flow that hes forcing into the downpipe at a 90 degree angle.

if he would have done it properly and blended in at like a 30 degree angle, there wouldnt be a problem.

see, i just wasnt being clear when i said the exhaust is restricting the wastegate flow

Now my turn:So explain why this photo also has a 90 degree entry from the dump pipe back to the downpipe and he has ZERO boost creep..My setup was very similiar, but my entry was further down the line. And i had boost creep...Can u explain this one..??

http://images.cardomain.com/me...l.jpg

Post by **TrunkMonkey** » Sat Feb 07, 2004 1:58 pm

i don't have time to explain, but it's much easier for the wastegate to pull the excess exhaust from a log manifold than it is from a tubular with a collector. think about it.

-demetrius

Post by **MaxType 240** » Sat Feb 07, 2004 1:58 pm

I have the F-Max Stg 1 on mine.

Dyno 1 w/ F-Max wastegate design: Dyno Results 1

I changed the design, here's info/pics on the redesign:Dyno Results II

I've dyno'd several times thinking the redesign did something for me but other factors are holding me down perhaps?

If someone says my new wastegate exhaust design sucks compared to the original, I'm gonna shoot myself...

Jesse

Post by **MaxType 240** » Sat Feb 07, 2004 1:58 pm

[quote=" rn240sx Now my turn:So explain why this photo also has a 90 degree entry from the dump pipe back to the downpipe and he has ZERO boost creep..My setup was very similiar, but my entry was further down the line. And i had boost creep...Can u explain this one..??

http://images.cardomain.com/me...l.jpg [/quote]

OK, that was my original design. I had creep but it was fixed w/ the AVC-R solenoid settings.

With the new design, I have mad boost creep, runs up to .61bar. Need to reduce the solenoid % some but is that not a sign of efficiency? The ability to flow more exhaust?

Trying to find my power is my concern, you deal w/ the boost creep

Boost Creep Problem after 2 changes

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