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TT This
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Discussion Starter #1 (Edited)
Alright as some of you know I got the Dave H intake in the fall last year. I made a few runs in late fall last year. I never got around to hooking my boost gauge back up until this last weekend. I have a 14.5 psi wastegate spring governing boost. I can only make about 12 psi boost max though. Prior to the intake install I would boost to 14.5 all the time no problem. The only thing different now is the intake (which must have a considerable increase in volume over stock), and I also changed out the cool side I/C piping from 2.75 to 3.5 inch from I/C to the throttle body. I've also switched to the Q45 throttle body but that shouldn't affect anything. SO does the increase volume of the intake and the I/C piping affect the boost pressure? I do have a 17.5 wastegate spring I was going to install here shortly, so I'll see if the pressure goes up with that spring installed...Anyone have any input?

 

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I wouldn't sweat it. The fact is you've completely re-plumb the delivery of air to the head, and it's much better than before. Consequently, you'll probably push more CFM of air at less pressure. Does that explain the drop in pressure? Probably not.

Getting the motor to breath better will change just about everything - when the turbo spools, volumetric efficiency, boost pressure, etc. However, all changes will be for the better.

I have a DaveH intake, and the car put down 630rwhp at just 24psi of boost on a very mild tune. Of course, that's with a T71, 264 cams (intake and exhaust), and a Greddy 4-row IC.

Am I glad I pitched the OEM intake? You bet. The new setup makes the air flow more efficient, maintenance is much easier, and the chance of a boost leak is substantially lower.

Don't worry about it... However, I it wouldn't hurt to double check for boost leaks.

-scott
 

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You're just running more efficiently than before. You should be able to make the same power at 12psi as you did at 14.5. Also a change from 2.75 to 3.5 is pretty substantial.

Check for boost leaks and work from there.

Do the car feel any less strong?
 

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TT This
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Discussion Starter #4
The car feels very good. I didn't even notice this until I hooked the boost gauge back up. It felt stronger than my stock intake for sure. I'll be checking over everything here in the next few days. I'm pretty sure I don't have a boost leak, but you never know...
 
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Glad you are running ok, guys...

Mine is still NA (need Dave to hook me up with a turbo manifold that fits mine!).

At 4000rpm, my car bogs down, seems to be the time in the stock system when the butterfly valve opens to make the runners the same length, so in top gear my car makes no progress! Also the mixture is running rich (or so I think) as the spark plugs smell of petrol, when I take them out!

Need turbo asap!
 

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TT This
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Discussion Starter #6
Just thought I'd update... I found my problem to be two things. One was my gasket between the tial wastegate and the exhaust manifold had blown from the sides. funny thing is I really didn't notice any exhaust leaking sounds. :scratch:



I also did a pressure test on the I/C piping and found a pretty substantial leak :takethat:
So I fixed all that crap and she boosts to about 16 now which I assume is as close to the 17.5 psi wastegate spring pressure that I'm going to get with the intake and I/C piping volume... thanks everybody.

Hey Wiglet how's things goin man... What are you using for fuel control? Do you have a wideband yet? I'd be interested to see what Dave's intake will do to the A/F when ran NA.
 
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Easy Ninety!

Just bought a SAFC2, I severed 3 fingers last week, had to have a tendon sewn back together, so can not do anything at the moment!

I am 99% sure that the car is running rich, as the plugs stink of gas, when they are removed to check! Hoping that the SAFC will allow me to trim the fuel to compensate!
 

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wiglet said:
I severed 3 fingers last week, had to have a tendon sewn back together, so can not do anything at the moment!
eek!! :eek3: I wish you a speedy recovery, but did this happen when you working on the car and does it mean you don't have 3 fingers anymore? eek!! :eek3:
 

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wiglet said:
Easy Ninety!

Just bought a SAFC2, I severed 3 fingers last week, had to have a tendon sewn back together, so can not do anything at the moment!

I am 99% sure that the car is running rich, as the plugs stink of gas, when they are removed to check! Hoping that the SAFC will allow me to trim the fuel to compensate!
If your running rich the plugs will be black...
 

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TT This
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Discussion Starter #10
wiglet said:
I severed 3 fingers last week, had to have a tendon sewn back together, so can not do anything at the moment!
:worthless

how did you manage that? maybe I really don't want to know :eek3: Is everything going to be alright? Full function regained? soory dude
 
W

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Err regarding my fingers, was cutting some fence posts with a compound mitre saw (circular saw) do not know how my hand got so near, but it did.

Going to hospital tommorow for physiotherapy, I can move my fingers, but could not make a fist, so hopefully when healed I will be able to.

Was on holiday last week (I am a teacher) got another week off sick, so annoyed as last week had loads to do!

Thanks for your thoughts.

Will post up a pic of my hand tommorow maybe!
 
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