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only ~6psi with 3"exhaust/TID?

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Old 06-19-04, 10:53 AM
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only ~6psi with 3"exhaust/TID?

hello friends,

i have been breaking in my atkins reman and i'm up to about 80psi on both rotors so i've boost a couple times just to see how high the boost would go with no boost controller or anything. i changed my oil at 500 miles and i'm at about 700 miles so i'm gradually starting to show the motor more load, etc. i havent taken it over 4000 rpms (i'll wait til the break in is over for that) i've only gotten into boost a couple times so dont think i'm reaming on my motor while it onl has 700 miles on it

but anyways, why will my boost only go to 6psi with my full 3" exhaust and my TID?
Old 06-19-04, 10:58 AM
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is the wastegate ported? with my 25mm wastegate i noly gto 6psi also
Old 06-19-04, 11:51 AM
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nope. and its an s5 turbo.
Old 06-19-04, 11:58 AM
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port the wastegate
Old 06-19-04, 12:01 PM
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wtf does porting my wastegate having anything to do with this post?

porting the wastegate lowers boost
Old 06-19-04, 12:07 PM
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I dunno I asked a rotary friend and that's what he told me... sorry
Old 06-19-04, 12:07 PM
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Sounds like me, I have a S4 T2 w/ S5 turbo with exactly the same mods as you and a ported wastegate. 3" all the way back, no cat and I get 6 psi... you should probobly be getting a bit more then 6 turbo in good shape ? . Boost controller should fix that up
Old 06-19-04, 01:03 PM
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did you check to see if the wastegate actuator is working? or if its even hooked up. does the boost come quick or is it laggy? do you still have the stock boost controler? also your FMIC might be the cause because of the longer pipes. and make sure the BOV isnt leaking. thats all i can think of now.
Old 06-19-04, 01:42 PM
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under 4krpm might be your reason.. that's all the boost I see below there, and I've got about the same mods.

once I hit 5-6k in 3rd though, it's at 10-11.



80psi on a fresh rebuild is crap compression, hopefully those numbers come up some more for ya.
Old 06-19-04, 01:43 PM
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if the wastegate actuator wasnt hooked up then the boost would climb as high as possible. it could SOMEHOW get stuck all the way open, but i doubt thats possible.

the boost is a bit laggy as well yes. and no i dont have the stock boost solenoid.
Old 06-19-04, 01:48 PM
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i had a similar issue when i had my CAT still on..

I removed it and hit 15psi.

swapped it with a RB Pre-silencer
Old 06-19-04, 01:53 PM
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How hard have you gotten on the car? Was it at WOT when you hit 6psi?
Old 06-19-04, 02:02 PM
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yeah WOT under 4k rpms. i've done it a couple times just to see what the boost would do. only for a second or two at a time. as soon as i saw where to boost would settle, i'd let off.
Old 06-19-04, 09:48 PM
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Well, sorry this isn't going to give you any answer, but I've been boosting 10/11 S5 for the last year. Today I go to pick up my wife from work, and the gauge stops at 5/6 and factory gauge only 1/2 way. I try it 3 times, and every time 5/6 lbs. I pick her up and try it on the way to the movies, same thing. Check all clamps, hoses, visually, everything seems fine. Come out of the movies and on the way home in second, right up to 10/11 immediately. Went to dinner and again on the way home, it jumped right up to 10/11 and ran fine. I dunno, I give up!!!!!!
Good Luck
Old 06-19-04, 10:50 PM
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interesting. i found 2 vacuum leaks today and fixed them and now i'ts hitting about 6-7 psi so its slightly better. hopefully my k2rd blockoff plates will cure the problem when i get them this week.

Last edited by jacobcartmill; 06-19-04 at 10:56 PM.
Old 06-21-04, 08:39 AM
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Is it just me or does 80psi sound weak for 700 miles...especially for soft atkins seals.
Old 06-21-04, 08:59 AM
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I will be troubleshooting a 6PSI limit the next few weeks.
It's a J-spec with the wastegate ported.
The plan:
1) Check the wategate linkages & operation.
2) Check the stock boost control solenoid & its hoses.
3) Upgrade the fuel pump.
4) TID mod.
5) CAI mod.
6) Replace gutted cats with downpipe.
7) Swap the old (was pushing 12PSI) turbo to the J-spec?
Old 06-21-04, 09:14 AM
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Originally posted by jon88se
Is it just me or does 80psi sound weak for 700 miles...especially for soft atkins seals.

Exactly what I was thinking. My rebuild has 0 miles on it (just running it to warm it up parked) and it has 90+ all the way around. What compression does atkins guarantee?
Old 06-21-04, 09:33 AM
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If you have an S5 turbo - and it's only making 5-6psi, make sure you have the stock Boost controller on there. The wastegate spring is only rated at 5psi -- S5 Turbos used an stock electronic Boost controller so that they would hit 8psi. Without it, it won't allow more then 5psi.

Plus, with the better wastegate design, I'm sure a TID/DP isn't enough to alllow more boost...

Get a BC, it'll solve all your problems.

David
Old 06-21-04, 01:32 PM
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no guarantee

porting affects compression
Old 06-21-04, 04:23 PM
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Jacob I bet the 85+ degree weahter isn't helping the cause either. I think once its broken in and a bit cooler you might see more psi with the mods you have...but maybe 8 max. Intake, down pipe and high flow cat on my car (yes its a IV not V) only yielded 8 psi when I really hammered on it or it was cool outside.
Old 06-21-04, 04:41 PM
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Originally posted by jon88se
Is it just me or does 80psi sound weak for 700 miles...especially for soft atkins seals.
i think i got a set of "not the best" rotor housings. the rotors were actually NEW (had a pricetag on one of them, perfectly clean)

the compression is in the 90's now, its just taken a while for the seals to seat. i have also been using MMO premixed in every other tank of gas.

as long as it gets over 100 by 1500 miles i'm happy
Old 06-21-04, 04:41 PM
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yo, 80psi on each housing sux, that's worse then my engine with 166k on the orginal iron good luck man!
Old 06-21-04, 04:54 PM
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yes, thanks for the news flash.

it only has 800 miles on the motor incause you missed that.
Old 06-21-04, 06:24 PM
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Originally posted by PilotSi The wastegate spring is only rated at 5psi -- S5 Turbos used an stock electronic Boost controller so that they would hit 8psi. Without it, it won't allow more then 5psi.
Is this true? Both S4 and S5 FSM say it should be open at 10 psi, but the FSM doesn't say when it should start opening, just that it should be open at 10.

Right now I have my S5 turbo connected like an S4 without the twin scroll crap and no boost controller, i.e. wastegate line hooked right up to the compressor outlet pressure. Is this why I'm only getting 5 psi boost?

TIA,

Scott


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