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Old 06-23-2003, 08:12 PM   #1
8Complex

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Default Deltagate vs. boost creep...

Now, I've heard stories of boost creep on Deltagates, but how bad is it really?

I have been building a car for a friend that has a Deltagate in it still (quite the shame) with a GT30/40 turbo and plan on running it around the 16-18psi level.

The funny part is, I drove it around for a while at 4-5psi and it never once creeped, but as soon as I got the fueling done, and an intake on the turbo, and coolany plumbed into the turbo properly, I was out tuning and the boost wasn't limited to the 4-5psi it was before. All of a sudden I notice that it just keeps going up to 8-9+psi. I haven't been able to test how high due to the fuel wall when the secondary injectors kick in (I haven't tuned up that high yet, so it's WAYYYYY too much fuel for sure).

Does anyone have any ideas if a Deltagate can really boost creep when set to 4-5psi?
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Old 06-23-2003, 08:55 PM   #2
kastle
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If you plan to run @ the same boost levels I do, you WANT the Tial. I had boost creep on the deltagates @ 12psi, pretty badly, when I had the TT setup. It would creep to 15psi, which was not good with the stock internals.


Just my .02
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Old 06-23-2003, 09:31 PM   #3
Sunrise City Rider
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They Creep with the low boost spring...They will hold with the stiffer spring...My friend was running 600HP out of his integra with 28psi using a simple Integra Drag Log Manifold and a T3/62-1 and the Deltagate...Of course he swapped to a 46mm Tial when he switched to an ITS T78 but the deltagate lasted over a year of 100s of dyno tuning and just as much drag strip runs...Took him to a 10.01 in a 2.0liter GSR...

Zee
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Old 06-23-2003, 11:01 PM   #4
8Complex

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Sounds like it also depends on to what potential of the turbo's ability the wastegate is set to.

I really want to get a Tial on there, but I have exactly $109 to finish this project, which includes getting a different oil return line made up (this one keeps freakin leaking! damned -10), and at least another tank of fuel. I don't think anyone will sell me a used one for $75. The owner is very tight on cash even, and this is almost a charity project... I may get something in trade for the labor, but at least so far I can say that the knowledge gained has been incredible.
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Old 06-23-2003, 11:06 PM   #5
Eric SS
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The one that came with the Ludespeed kit (first run turbonetics) works fine for me at 10psi with the 7-9psi spring in it.
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Old 06-24-2003, 02:05 AM   #6
8Complex

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This one is from a VERY early Minnam kit... like the 6-7th out the door. It has a 5-7psi spring, so I don't wonder if I can just swap it and the one I've got sitting around from my Ludespeed kit and see if it works ok... wonder if the design had changed...
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Old 06-24-2003, 04:26 PM   #7
JST
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The one i have was creeping at 5psi to 8psi. I install a turbonetics MBC and set it at 8pis and now i have no more boost creep!!
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Old 06-24-2003, 05:11 PM   #8
Sunrise City Rider
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All those Deltagate swap, no matter what version it is...

I think the Tials swap over too...

Zee
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Old 06-24-2003, 09:28 PM   #9
milkman
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Default Deltagate II racegate

With the 5-7# spring, works good for me over a year now. All most switch to the Tial but couldn't see why. The only thing I see is maybe 1/2# over the set poundage when first getting into to it.
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Old 06-25-2003, 03:38 PM   #10
Pavlo
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Seems people are confused between wastegate creep and boost creep.

A wastegate with a 10psi spring means it just starts to open at 10psi. TO actually limit boost to 10psi, it may need to open more than the "crack" you see at 10psi, so boost will actually be higher by perhaps a psi or so. THis is not boost creep, it's normal, and depends on how the spring rate and preload are balanced.

When have a 10psi spring but your boost is only at 8psi till high rpm, this is wastegate creep, caused by the gate being blown open by the exhaust gas back pressure. It's this that will be solved by using a boost control system of some sort.

Boost creep occurs when there is just too much exhaust gas to cope with, with raises boost, which creates more gas, so it's a vicous circle, which when at it's most extreme will mean very high boost with no spring at all (ie wastgate just open).

But in answer to you 8Complex, TiAL now do a 38mm wastegate with Deltagate compatible flanges, which may help you if you are getting real bad creep. And it sounds like you might do. THe other thing to check is good flow to the WG, so a sharp 90º tee into the up-pipe isn't the best way to get good flow through the WG.

Paul
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