Loosing boost above 5k RPM, I have HB DV's....do I need better?

[speedtrapped]

Mr. Hall has been kind enough to alert me that I am loosing boost above 5k RPM, I have basically new hyperboost DV's installed(500 miles old) I spoke with stratmosphere this am, they are telling me the DV's are rated 28psi...hmmm...as far as all hose connections, all triple checked and tight, and new since engine swap, w/ vennair's and oem. I wonder if i can use forge springs in the hperboost? If not, Is forge 007's the way to go because of the tunability?

[V8weight]

Neither the Hyperboost or the Forge valves can physically bleed boost. The pressure is against the side of the piston, not the bottom. The springs only purpose is to control how quickly the valves open and close. How much boost are you losing? Your probably just tapering due to the wastegate springs.

[speedtrapped]

well u reply might answer my question, I know that my exit which is the side outlet is piped into Y pipe, and bottom of the DV is hooked into turbo...so backpressure is pushing on bottom of pistion, and blowing off outside into Y pipe....do I need to reverse?

[DHall1]

Could be wastegate springs but the turbos are upgraded and they hold 2300mb just fine up to that point. Backpressure could be an issue but the entire exhaust is also upgraded. Diverters are easy enough to bench test. How old is the N75 on this engine? Do you have specs on the turbos? a/r sizes

[speedtrapped]

the n75, waiting on a response from dion....brb

[DHall1]

from memory of the log. Its not like the boost is crashing over 5k. Its just starting to taper down while the requested is still high. With the upgraded turbos and exhaust you should not be seeing this so soon. Boost is still well over anything a stock turbo can hold so we may be looking at the limit. But, still need to ensure the simple stuff is working. d/v and N75.

[speedtrapped]

what about the race n75 that ecs sells. It holds wastegates closed a little longer

[speedtrapped]

how would I bench test a DV?, tire pump and some duct tape?

[JSRS6]

what about the race n75 that ecs sells. It holds wastegates closed a little longer

Nope.678

[V8weight]

well u reply might answer my question, I know that my exit which is the side outlet is piped into Y pipe, and bottom of the DV is hooked into turbo...so backpressure is pushing on bottom of pistion, and blowing off outside into Y pipe....do I need to reverse?
Stephen, your understanding of the diverter valves is as backwards as your mass air flow sensors. :) The hose coming off of the y pipe is the pressure side, or inlet to the diverter. The hose coming out of the bottom of the diverter valve is the dump side, and is routed back to the turbo inlet. Your pressure hoses off the y-pipe should be pushing against the side of the piston, thus no chance of boost creep unless the O-rings in the valve are physically damaged.

[V8weight]

The ECS N75 is just a slower reacting valve that allows your car to spike boost.....your ecu will hate it.

[speedtrapped]

Nope.678

elaborate please.....

[speedtrapped]

ok, so n710's stronger then HB DV's? thats what was on the engine, I removed because I thought HB would prove stronger. Pat doubt a ring is bad, they are basically new, and I did not screw with them.

[JSRS6]

Stephen, your understanding of the diverter valves is as backwards as your mass air flow sensors :)

:lovl::lovl::lovl::lovl:

[JSRS6]

elaborate please.....

What pat said. Let the ecu do the work.

[speedtrapped]

well Dave the peanut gallery seems to think besides me being an idiot, that my dv and n75 are ok, i am trying to find out what springs are rated for the turbos, but DBR has not responded to my email yet.

[DHall1]

Did you change the diverter valves on this engine? I seem to remember you making a few changes to the setup.

What was on the engine and what is on there now? diverter valves.

It still can be the N75. Didnt answer how old it is yet.

[speedtrapped]

n75 is original....the dbr set up had n710 DV's but assumed the hyperboost was stronger

[DHall1]

You know what they say about assumed.

Change the N75 valve and take two Aleve. Call me in the morning.

[speedtrapped]

si, gracias

[marklar182]

Have you tried running the DV's backwards? They definantly should hold the pressure that way. (I believe a few here run them backwards as well)

[skribe]

You get a very subtle little boost venting sound when you flip the DV's. Which i think is kind of cool. But I have all the maturity of an eleven-year-old on a pop rocks bender.

[speedtrapped]

I will give it a whirl, once I'm done burning some ants with a magnify glass. Ordered stock n75 and I will switch dv orientation, data log end of week.

[yokust]

From personal experience, every HB valve I have put in on 1.8 or 2.7. They hold horribly in "original" position.

But when flipped to "correct(but not oem)" position they hold great, have a better sound.

I have a pressure checker I made for DV's I will hunt it down and take a picture of it

[speedtrapped]

yokust, thank you for that, i plan on reversing them, if u can find a pic that would be awesome!!
Stephen

[DHall1]

Who was it that said diverters again?


yokust, thank you for that, i plan on reversing them, if u can find a pic that would be awesome!!
Stephen

[speedtrapped]

U mr hall, but yokust was the first to share a similar problem with HB, unlike some of my compatriots here who enjoyed pointing out my ignorance:hihi:

[arS6]

how would I bench test a DV?, tire pump and some duct tape?

You can check to see if your DVs are leaking simply by pushing the piston down and holding it with a...pen. Then at the same time place your finger on the vac port, and then release the pen. The piston should stay in place (open). If it doesn't, then your DV seals are leaking. That's how I test my Forge DVs. Good luck.

[speedtrapped]

TY arS6...I will test them

[JSRS6]

That's a great, simple and easy way to test the seals. However, the problem Stephen thinks he is having is the letting off boost pressure. For this test, you will need to make a tester. I forget the diameter of the dv ports...1.5 inches? Regardless, get a PVC end cap in that size. Drill a hole(I believe it's 7/16, but it might be 1/2 inch) and pull a valve stem through. It shoulnt be easy, if it is the hole is too big. Valve stems are super cheap. Two hose clamps. A short length of hose to attach the end cap to the bottom port of the dv. Once everything is connected, start pumping with a bicycle pump with a gauge. See how many psi the spring and seat seal holds.

[speedtrapped]

Ty Macguivere, ah josh -will do this weekend

[JSRS6]

No problem ;-)
http://images.dvdsetshop.com/upload/uploadfiles/macgyver2.jpg

Gonna go strap another rocket to my beast now.

[speedtrapped]

lol, nice

[Aronis]

on the line of this thread!

I can hear the sound of some kind of air leak at about 3500 to 4000 RPM (Only when the car is in gear, NOT when parked), but there is not real noticed loss of performance by butt dyno.

I could not find a loose hose, as best I could see.

Did did the VAGCOM log for the boost level and the actual matched the requested.

So what would you think the leaking point is?

If I had a small boost leak would that show up in the logs?

Thanks,

Mike

[speedtrapped]

Mike,
In my situation its a small boost bleed, per se....above 5k rpm, spec is 2350-2400 and actual will read 2300, next several secs down bleed down 2000, 1950.....now since my engine swap i can confidently say, charge pipe connections are new, and vennairs are new...u checked SMIC's? if they are stock, I would bet you lunch, they leak, stock are awful...I had no leak issues, and switched to wagners because I figured I would be going bigger turbo, bench tested my smic's, viola..leaked, both of them

[Aronis]

I guess I'll drive it as is for now!

Swapping intercoolers is too big of a DIY at this time. I'd try but need a backup car!

Thank you.

Mike

Maybe I can spray some fix a flat in there! Lol

[speedtrapped]

Mike, if u like u can have my stock for 200.00, there are some diy to seal them, pretty easy fix....they are sitting in box

[Aronis]

Thanks for the offer!

I saw some oily sooty stuff on the bottom of the drivers side IC about 6 months ago. I cleaned it and it's now back!

If it's leaking from the front side I can JB weld it in place!!

If not then I'll live with the small leak until it causes a noticeable issue.

Thanks for the help!

Ps: If I were to go through the work to swap out the IC why not just seal my own!! Just saying!! But I'd probably go ahead and install new IC s. The time required to DIY is the more expensive item than the $2000 aftermarket kit!



Mike

[DHall1]

If only 1 is leaking. You could buy 1 OEM IC.

Time savings is the benefit of picking up a set of used and resealing. You can take you time resealing and be ready for install then sell your stockers to the next member.


Thanks for the offer!

I saw some oily sooty stuff on the bottom of the drivers side IC about 6 months ago. I cleaned it and it's now back!

If it's leaking from the front side I can JB weld it in place!!

If not then I'll live with the small leak until it causes a noticeable issue.

Thanks for the help!

Ps: If I were to go through the work to swap out the IC why not just seal my own!! Just saying!! But I'd probably go ahead and install new IC s. The time required to DIY is the more expensive item than the $2000 aftermarket kit!



Mike

[speedtrapped]

Reversed the DV's, still haven't swapped n75, let a speed junky take her out with me as passenger. I wanted to see if he was impressed. He owns an rs6 Giac chipped and an overtop NSX, he sends away every year to have turbo work done in chi-town, 1000hp. He loved top end, my beast has tons of top end pull, but he was a little let down, that my car wasn't more explosive under 3500 rpm, which I admit a good tune should fix. Can't wait for the custom tuning, i have found out the new dbl secret test track, 3 weeks...2 mile long abandon airstrip, 20 miles from my house....so racelogic fans, 3 weeks, 60-130, top speed( never done that before)

[MaxRS6]

^Wooohooo- I look forward to that report

[ben916]

Lakehurst?

[speedtrapped]

wow Ben, no sir, its an abandoned municipial airport, that a wealthy person bought property that has house he lives on. I am only keeping it hush and def not sharing on audizine, because I was invited.

[Beastly]

speed - did you ever sort this out? Would like to hear your progress thru this.

[speedtrapped]

I reversed DV's, and I have a new n75, yet to be installed...hopefully this weekend. The boost drop off is very minor above 5k rpm, but I will log soon and repost