Rajicase's First Turbo Build, Ballin' On A (Nonexistent) Budget

[crazyyardie]

20ish. I have a digital boost gauge and the hose for it is like 2 inches right off manifold. Highly doubt it's leaking. But I will boost leak test before it gets back on the road.

Out of curiosity, what are you getting at?

Which bov and spring were you running ?

[vollosso]

Tial and whatever their lightest spring is

[pbonsalb]

I think the one most of us use is the plain spring. My bov flutters at idle vacuum and is often partially open. My gauge typically shows around 19-20 inches at idle but the eboost2 gauge may not be 100% accurate.

I have a used Tial 50 mm BOV for sale with new steel weld flange and oring if anyone is interested.

[flyfishvt]

M Innovate SCG-1 reads 20 at idle too. I always thought that was a little high. Maybe not.

[Butters Stoch]

Tial and whatever their lightest spring is

Tials lightest spring may open in boost. Unpainted should be used, 16-19 in/hg

[rajicase]

Tials lightest spring may open in boost. Unpainted should be used, 16-19 in/hg

Yes I am using tial 50mm.

It's absolutely wide open at idle. I'm thinking it's staying open way too long. Certainly hurting spool significantly and again,only getting 5 psi on 7.5 psi spring set up.

Maybe I have another boost leak, I'll test tomorrow hopefully. But that bov has to be causing me problems I'd think..

I picked up the unpainted one from busterhax today.

[rajicase]

I think the one most of us use is the plain spring. My bov flutters at idle vacuum and is often partially open. My gauge typically shows around 19-20 inches at idle but the eboost2 gauge may not be 100% accurate.

I have a used Tial 50 mm BOV for sale with new steel weld flange and oring if anyone is interested.

Same bov I have. Cracked at idle I think is fine. Mine is wide open.

[vollosso]

Tials lightest spring may open in boost. Unpainted should be used, 16-19 in/hg

i use synapse with a preload bolt

[pbonsalb]

Are you sure it is staying open under boost, at least as you go into boost? How do you know? I doubt even the weakest tial spring will open under the 7 psi you are running. Your problem may be elsewhere. For a cheap test, shim the spring with a large washer or two

[rajicase]

Idk if it's open at all under boost, but I'm pretty sure it's staying open longer than it should which would explain my slow spool, yeah? I mean it's completely open at idle which is certainly incorrect.. and also has way too weak of a spring for s52 application. Seems logical ?

And I'm not even getting 7 psi. I'm getting 5 psi on a 7.5psi spring set up.

Possibly my wg is opening early?

[MisterM52]

How much have you spent so far though? And how much are you expecting to pull out of it when you are done?

I bought myself a Turbosmart Dual port BOV recently, US made afaik. It may be your Spring in the waste gate, friend was having same issues..

You haven't even lit the match that lights the fire yet.

Turn the wick way up, maybe 4 times that 5psi. But at your pace, don't be foolish, you truly now have a weapon that can be pointing in your own mouth if your not careful. I suggest not going too heavy into throttle around corners just yet.

totally Raji, 20 PSI is where its at.

[pbonsalb]

Idk if it's open at all under boost, but I'm pretty sure it's staying open longer than it should which would explain my slow spool, yeah? I mean it's completely open at idle which is certainly incorrect.. and also has way too weak of a spring for s52 application. Seems logical ?

And I'm not even getting 7 psi. I'm getting 5 psi on a 7.5psi spring set up.

Possibly my wg is opening early?

The BOV is certainly worth looking into, but I am doubtful it is your problem. I just don't see any spring Tial sells not holding 7 psi boost. The BOV is not like a WG where you change springs to control boost. You change springs in the BOV so you have one that just barely keeps the BOV closed at idle. If you read the Tial BOV instructions, there is no mention of spring ratings by PSI or engine sizes. The main concern with an open BOV is that air for which fuel has not been metered could enter, but this is not a concern on a blow through system with the BOV located before the HFM. You might be able to secure a phone under the hood to video the BOV while you transition from vacuum to boost. I think you will find it is fully closed with a little more than idle rpm and a little more than idle throttle.

I would be more concerned if your BOV was not getting manifold reference boost/vacuum or getting vacuum only. Make sure it is not in a check valve line or a leaking line.

The WG spring rating is just a rating for ideal circumstances. You could get a little more or a little less. But more often people tend to get a little more. You might double check to see what the spring is unless you ordered it and know for sure because you installed it. Maybe you really have a 5 psi spring. Also check how you are setting up the WG ports -- there are a couple of methods for the typical 2 port WG. Not sure one is any better than the other, but if you did it wrong, like used only the top port, there could be issues. For trouble shooting, bypass any boost controllers and any other taps off the reference line. Should go compressor discharge to WG.

But bear in mind that 7 psi at the turbo discharge could be 5 psi at the manifold where your boost gauge is tapped. This might be due to a boost gauge that reads 2 psi low or it could be due to restrictions in the IC piping or intercooler, or it could be due to a boost leak.

I would keep looking for boost leaks. Butters sells a boost leak tester that is easy to use (but you need a compressor). We have used them to find leaks around the HFM, a split in a boost hose, and other leaks. Sometimes a leak opens up only under boost.

While I understand most people here can buy, install, tune and troubleshoot a turbo system on any E36 in an afternoon, it takes some of us a little longer to fully sort out a turbo conversion. Be patient and keep at it.

[rajicase]

BOV is getting its reference directly from intake manifold. I tapped and threaded/epoxied a two fittings into my manifold(one for BOV and one for boost gauge).

The spring set up is correct, I installed them myself.

I also installed a plugs according to Tial and am currently not using a controller, just running wg pressure. My WG reference is right off the compressor housing.

I will make a boost leak tester and check for leaks asap. Just gotta get some free time..

And yeah, Im really pleased for now. I mean it runs great, so I consider this a small issue in the scheme of things...

- - - Updated - - -

I think I have spent in the $3800 range on the turbo set up. But I have 2 turbos and 2 manifolds and 2 motor mount arms. Spent a rather big sum on a boostlogic manifold and scavenge pump. Went a bit over budget, but for a full running set up with almost all high end, name brand parts... Cant really complain. That boostlogic manifold is a piece of art , I feel lucky to have one....

How much have you spent so far though? And how much are you expecting to pull out of it when you are done?

I bought myself a Turbosmart Dual port BOV recently, US made afaik. It may be your Spring in the waste gate, friend was having same issues..



totally Raji, 20 PSI is where its at.

[Butters Stoch]

. My WG reference is right off the compressor housing.

Ummmmmmm that's why your seeing only 5 psi on a 7# spring. Due to pressure loss.

Go off manifold, change the spring , or put a MBC/EBC in there.

[rajicase]

Ummmmmmm that's why your seeing only 5 psi on a 7# spring. Due to pressure loss.

Go off manifold, change the spring , or put a MBC/EBC in there.

Well at least we know the manifold has good boost control.

Could a super low wg spring set up hurt response / spool? If it's cracking open early?

[Butters Stoch]

Well at least we know the manifold has good boost control.

Could a super low wg spring set up hurt response / spool? If it's cracking open early?

Anytime your running off WG spring without some type of controller, it will naturally crack open as it sees pressure. This is what makes an electronic controller so valuable. It clamps the signal to the gate so it sees no pressure till your desired set point. Even a MBC will bleed off a little keeping it shut longer.

[bry195]

If you are idling you have X amount of vacuum in the manifold. How much X? Depends on the elevation you drive in.
-7psi of vacuum in the manifold requires a -7 or -8 psi spring to keep it closed at idle.
When you throttle the car the manifold vac goes from -7 towards 0 or beyond to a positive pressure.
The spring is to keep the BOV just barely closed at idle. As vacuum moves towards 0 or positive the pressure in the manifold finds itself adding spring force to the BOV holding it closed even harder than just the spring.

-Xpsi is an unusual measurement but its good to work in these units for the purpose of the explanation. InHG, INH2O,.....it all converts.



2 schools of thought.
1-set the spring up to barely keep it closed at your elevation.
2-set the spring to keep it closed at any elevation (sea level).

[pbonsalb]

OP is low elevation but referencing boost gauge from intake manifold and wastegate turbo so there is a difference. That is to be expected.

[hsvturbo]

If we assume the gauge and spring are correct, then you have 2.5 psi drop across the 12x3 FMIC. Is this a bar and plate design?

[rajicase]

If we assume the gauge and spring are correct, then you have 2.5 psi drop across the 12x3 FMIC. Is this a bar and plate design?

I'm not sure?

Is a cheap ebay ic. 2.5 psi drop reasonable or too much?

Actually my spring set up according to the tial chart is 7.25 psi. So assuming 2.25psi loss.

Also my aem digital boost gauge only reads whole numbers so it could be a bit over 5 psi. So we can say it's losing roughly 2psi.

[hsvturbo]

I'm not sure?

Is a cheap ebay ic. 2.5 psi drop reasonable or too much?

Actually my spring set up according to the tial chart is 7.25 psi. So assuming 2.25psi loss.

Also my aem digital boost gauge only reads whole numbers so it could be a bit over 5 psi. So we can say it's losing roughly 2psi.

IDK, but I'm interested in this as I plan to add a 4" bar and plate IC to my car. Treadstone advertises a 1.5psi drop at 760 hp on thier 12.5 x 3.5 intercooler.

[Butters Stoch]

I'm not sure?

Is a cheap ebay ic. 2.5 psi drop reasonable or too much?

Actually my spring set up according to the tial chart is 7.25 psi. So assuming 2.25psi loss.

Also my aem digital boost gauge only reads whole numbers so it could be a bit over 5 psi. So we can say it's losing roughly 2psi.

I tossed my AEM digital boost gauge over a bridge cause it was off by 2 psi. I confirmed that by a snap on gauge, 2 different mechanical autometer gauges and an Eboost2 .

[familyMAN]

Boost gauge? You guys are funny. Pick the hp you want and that your engine build and fuel system and octane can handle. Then select a turbo that just meets those requirements. Put in an appropriate WG spring, install MBC and keep cranking it up until it stops making power...confirmed by dyno or track or 70-90 times.

[bry195]

Poor mans (super accurate) pressure loss gauge.

For example-T the signal line from the compressor to the manifold or BOV with a clear silicone tube and an ounce (or whatever) of water in the tube. The tube should have a low spot below the compressor outlet and manifold. An M shape will get you around ground clearance issues and if you want the center point of the M can be above the compressor. The compressor outlet pressure will push the water in the tube towards the manifold. As measured perpendicular to the ground (not the arc distance) the water will move say 10 inches vertically towards the manifold. This 10 inches of water column can be converted to PSI or whatever you prefer. Its a direct reading of the difference in pressure between the 2 ends of the tube and more accurate than most gauges on the market. A little water in the manifold shouldn't be a problem. Don't hydrolock your motor with a gallon of water.

You could even run enough silicone tube to watch the water column in the cabin. However, there is pressure loss in the silicone tube. Make sure the center point of the M in the tube has the same distance from the center point of the M to the compressor and the manifold. You want the pressure drop in the silicone the same on both sides of the sample point and then your results don't need fancy math.

You can also use this to determine the spring needed in the BOV.

[GG///M3]

Sadness awaits. That is all.