I pretty much finalized the turbo bracket.

I used 3/16 plate, and contoured it to leave more metal around the bolt holes.

 

Test fitting bracket, using 1 bolt during mock up

 

The big moment.....

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Spent more time on the mount today.

Trimmed the wide side so now it's symmetrical

Had cut the dp about a half inch shorter (where it meets the turbo) than I'd like, but that was necessary to get the overall width down, to clear the lower trailing arm. Good thing I remembered to put in the lower (rearward) flange bolt bc the tight radius of the dp would not allow installing it after the flange was tack welded.

Then I cut off the outlet to give about 4-1/2" of ground clearance.

Dad patched up the y-pipe with the tig bc I kept blowing through it with the mig.

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Its difficult to see but there's about a 1/2" between the dp and the lower trailing arm.

It's funny.....for such a big car there's not a lot of room for stuff.

 

I hope I don't have to move the Atomic efi wbo2 to the dp, bc it's so short I'll undoubtedly experience reversion.

 

There is plenty of room, just a bunch of sheet metal that needs to be relocated

 

Best Christmas gift. Ever

 

Either deal with the reversion or deal with bad O2 readings. The WB02 doesn't like being pressurized.

 

I agree

Any suggestions for either case?

 

Just go over the axle with the exhaust, it will get you the length you need and make it nicer to drive. All that would take is a couple U bends or 120°s

 

To clarify a bit...

Let's assume I leave the wbo2 in the y-pipe, pre-turbo (in spite of the fact that it's highly recommended NOT to): Can anyone tell me whether the efi will "think" the mixture is too rich or too lean under boost ?

I can try to tune the boost fuel table to compensate for that false reading if I know which way to go.

I get why it's not wise to have the wbo2 pre-turbo because the Bosch Technical and Bosch Trade brochures state their sensors "draw their reference air from the connector and through the wire harness" so I can guess if the sensor sees too much pressure it won't allow in enough reference air into the sensor.

Also can anyone tell me what the minimum recommended length of the dump pipe should be to lessen or eliminate reversion? I've read minimum 12 inches for dp.

Lastly (for now) if I do put the wbo2 in the dp, can it go right up next to the the dp flange where it bolts to the turbo?

Initially, I am going to run a 4psi wastegate spring, so I'm confident the wb02 pre-turbo won't be a big issue at first.

Eventually I'd like to change the 4psi spring to an 8 (or whatever spring it takes to "see" 8 psi on the boost gauge) so wbo2 placement will likely be much more important.

 

Thanks B E N.

I think you're probably right.

Then I'm done. Period. Move the wbo2 post turbo and be done with it.

 

There must be some forgiveness in the o2 sensors and pressure. Its hard to say how much, but most exhaust systems have some pressure in them, and the pressure changes cars see with altitude and weather.

But why go halfway? You are in the fabrication stage now, just set it up the way you want it to be.

Edit: I think we were typing at the same time.

 

You're going to have plenty of back pressure with the small turbine, i'm going to say it'll be backed up, and pressures climbing fast by 4500 rpm. I may be totally wrong, but I think you're sorta wasting your time with this setup on something that makes 260 whp na.

 

shit

ok

thank you

 

Take it for what it's worth, it's just my 2 cents. At the stage you're at, it's easy to change to T4, and keep moving. The 3582 is worth more now than after it's been run for 10 minutes, no one wants a used China turbo. I also think that a single T4 will be better than twin 3582's, that's one extreme to another. A cheap S366 is a little larger than the 3582, but smaller than a Gt45 so it should fit decent. The only drawback is that they're a little more expensive than the dirt cheap 45's. Again, just what I would do, so take it as that.

 

understood.

thank you Mnlx

 

If you look up the spec sheet for the 4.9 sensor....it should have info showing the percent error at lambdas away from 1 and a higher pressures....

But, yes....skip the BS and put it after the turbo

 

Agreed. Thank you ss496 for that.

Wbo2 will go after the turbo.

Any delay in the signal traveling an extra 6 feet is negligible when compared to the tuning headache.

However, here's a graph if anyone's interested.

I'm not sure if it's for the 4.2 or 4.9. The only difference between them that I have found is the 4.9 has a higher heat tolerance.

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