Here's my setup:

B20vtec

Sp fab A-spec manifold

T4 Turbonetics twin scroll bb 60-1

Tial 38mm with small green 7 lb. spring

3" open downpipe

Greddy type s bov

My tuner and I did a little street tuning yesterday and ran into some pretty severe boost creep. 7 psi spring seemed to hold ok until around 6K rpm, then it would creep to nearly twice the spring rate... QUICKLY!

I know people make a lot more power on tial 38mm wastegates than what I'm shooting for (around 300-350whp).

Any good advice on fighting this boost creep would be greatly appreciated.

Chime in if you need me to provide any more info. Thanks, H-T!

 

Pics of manifold and dump tube

 

problem is your wastegate is too small for such a large turbo and low boost. also the collector setup on the a-spec manifold is not ideal either.

get a smaller turbo would be my first answer. why such a large turbo for low hp goals? your normal 50-57-60 trim would be way more responsive and be in a more efficient part of the compressor map.

 

Hard to get a good pic of the dt, cramped CRX engine bay ftl.

 

Hmm, well I acquired this turbo in a trade so I thought I'd give it a shot rather than drop serious coin on a new snail. My original plan was to run a quick spool valve. Surprisingly though, this turbo is making 8psi at 4k which is def less laggy than I expected it to be without the qsv.

As for the collector, are you referring to how the runner to the wg is one-sided and at a 90 degree bend? That tubing will accept a 44mm wg also. Think I'd be better off with that?

 

Those manifold always creep on me. I would say that the turbo size really wouldent help much. See how its kinda just in there like a T. The pressure kinda blows right past the T


A 44 would help but a 60 should cure it. Also if you shortened the length of the T it would help.


How many bends are in the dump tube? I seen that change things up too.

 

what is the diameter of the pipe to the wastegate? putting a larger wastegate on it won't help if the pipe going to it is the same size.

 

The pipe diameter is 44mm. Really not sure why somebody opted to weld on a 38mm flange, but that's how I purchased it. With the bigger tubing to the flange, it bottlenecks. :/ I'm sure that isn't helping matters.

 

Is it just me or is that turbo clocked at a crazy angle ?

 

tial wastegate?? old school tial? or copy?

looks nothing like tial, were did you get the spring could be a copy as well i had the same issue after buying a "tial" spring off ebay

 

Kyden is right.
Get a smaller turbo to match with the smaller wastgate, or use a Large wastegate, (either a 44mm or 60mm) to bleed off all of that boost for that measly 7psi. The wastegate placement isn't ideal but it would work with the A-spec fine, if you get a proper wastegate.

 

na its not you. that oil feed and consequently return line is no where near optimal...

 

Holy ****!! you're right.. He's over 35* angle on the cartridge..I missed it the first time I saw this. Better get that center section going straight up and down.. It may "seem" to work now, but I"m just waiting until oil feed issues destroy this thing.

OP, you need that at a perfectly vertical angle...

 

Thanks for all the tips, fellas. I'll re-clock the turbo and look into a bigger wg.

 

I just wanted to update this for those that were concerned. I have the 60-1 perfectly vertical now. Feed and return lines are good. I shortened the T pipe from the manifold by half its original length. Switched from the 38mm gate to a 44mm gate with a 4 psi spring and 44mm dump pipe that's perfectly straight. I'm still having creep, but it's minor, from 4 psi to 7 psi and holds there.

I got with my tuner yesterday to dial it in on spring pressure, but we got rained out. We are shooting for tomorrow now. Any of you guys with boost by gear setups think we can tune to 12 psi on the 4 lb. spring from where the boost stops creeping at 7 lbs?

 

I think you could tune to 12psi on a 4 psi spring but if your creeping to 7psi already... can you just put in a 7psi spring?

Congrats to you that you got your boost creep issues under control. You should take another picture!

I also didnt notice the oil feed lines poor angle... good eyes from HT guys. This website has some smart people!

 

I would agree with this. The turbocharger is large (using a P-trim or even o-trim exhaust wheel) with a small wastegate at Very low boost. The is the cause of most boost creep issues, other than wastegate placement.

Glad you got it straightened out.

 

Post tune update:

I'm a bit ashamed to admit this brochachos, but yesterday was full of fail. :/

Little background:

On Saturday, after reading that your fpr should have its own dedicated vacuum line, I decided to install a Golden Eagle vacuum distribution block that I'd been sitting on for a while. The install went great and now every component requiring a vacuum line is sourced from the vac block. The Bov had a new, stronger sound popping off and I'm sure the fpr was loving life too!

Keep in mind that before the vac block install, my boost gauge was showing 4 to 7 psi and holding. Of course the gauge now has its own line from the vac block too, which I believe deceived me.

I didn't figure this out until my first pull yesterday with my tuner. He set boost cut from the previous 13 psi "all tire fire" to like 8 psi. We hit it right away. Raised it to 12 psi. Same thing the following pull.

So I'm still creeping about 10 psi by 7200 rpms. It's just coming on a little slower now with the 44mm gate, which enables the car to actually hook in 3rd but still leaves us unable to dial in the boost by gear.

We even tried adding 4 degrees of timing. This brought the creep down below the boost cut, but the plugs showed signs of detonation. Pulled half a degree of timing iirc and hit boost cut. :[

Btw, vtec is set at 5200 rpms and all creep is happening after vtec engages.

This sucks! No worries though, we will NOT let this car get the best of us. Even though I felt like driving it off a cliff yesterday! I know one of you mentioned a 60mm gate, but after looking at the dimensions on one of those bad boys, I don't have room for one lol! without moving things around in the bay that I'd rather not.

What I'm leaning towards now is adding another 44mm gate to the other side of the mani. And running a 4 port solenoid for the bbg, if the additional gate will control the creep. What's your thoughts, guys?

A new, more suitable turbo just isn't in my budget right now, unless TheShodan has an interest in this T4 beast and wants to trade me something straight up! PM me if so, good sir. Haha, but honestly, I like this turbo! It's wild! I just need to tame it.

I apologize for misleading you all and I appreciate all the help and suggestions.

 

you need to get the gate better priority

 

Are you referring to its boost reference line? Or the gate's need to be "tear dropped" in line with boost flow from the collector of the manifold as opposed to its current T off the collector? Are either one of those assumptions in line with what you're getting at?

 

the gate needs a direct blast of exhaust gas, a 90* angle port does not provide that...take the gate off and do a pull (3rd gear), let me know how much boost you generate

 

Ok, I'll give it a shot. I too would like to know the results. I'm struggling to get my brain wrapped around your suggestion. Others have said the same thing. I guess when I think of popping a hole open in a pressurized system, the air will be forced out under pressure regardless of where the hole is located. So I'll pull the gate and report back. Thank you.

 

Hehehe, sorry my friend,.. no-can-do

 

don't think of it like that, think of it as the exhaust gas is going to follow the path of least resistance, the turbo system should always be at a 1:1 back pressure ratio (intake vs exhaust) and if you can maintain that or close to it, there is no 'pressure build up'


now with poorly designed turbos and kits, where backpressure is through the roof, it will get more exhaust gas to the wastegate just because of the traffic jam you have going on in the exhaust side of things

 

Dern!! Lol, well now I know you're aware at least. And if you're anything like me, this will weigh heavy on your conscience at night and cause restlessness and possibly restless leg syndrome! <--- you don't wanna get none of that on you! I'll even sweeten the trade with a bottle of Benadryl so you can rest easy. :] That's good for allergies too. Spring is upon us. Wth, while I'm throwin' out bottles, you fancy Jameson Irish Whiskey?!

I see. Those examples make sense.

So I just got back from making a "no wastegate" 3rd gear pull. Forgive me because it was hard for me to watch the boost gauge constantly and the street in Mexico I was traveling down, but at the peak of my pull I saw roughly 6 lbs. of boost. Take into account my gauge being slightly off and add 1 or 2 lbs. to that for a total of 7-8 psi approximately.

Thoughts?