Midpipe, Before and After
#1
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Midpipe, Before and After
About a month or two ago I put a catless midpipe on my car as opposed to running the previous stock cat. I had the chance to have my car on the dyno before and after so I have a boost plot.
My car is running the stock twins in parellel, With the midpipe i did pick up alot of spool time, and the car seems to be making a little more horses everywhere, however im not getting boost creep like everyone says i should be? am i just lucky?
(main point of this post is to give people a real graph of boost before and after a midpipe on the stock twins)
catless is red, stock cat is purple
My car is running the stock twins in parellel, With the midpipe i did pick up alot of spool time, and the car seems to be making a little more horses everywhere, however im not getting boost creep like everyone says i should be? am i just lucky?
(main point of this post is to give people a real graph of boost before and after a midpipe on the stock twins)
catless is red, stock cat is purple
#3
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No, thats not true. You can get creep with non-seq as well. Past 4,500 RPM the two types (seq and non-seq) operate exactly the same way.
Every car reacts differently. It depends on a multitude of factors. What are your other (relevant) mods?
Rob
Every car reacts differently. It depends on a multitude of factors. What are your other (relevant) mods?
Rob
#5
Rotary Freak
Soem people creep some don't. When I was going to put my midpipe on I was ready with a restrictor plate and everything, but I never got creep, so I never put on the restrictor plate.
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#9
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Its not bad for smell, (i idle my car around 13:1 afr)
but it is a bitch to start now that its cold out, usually takes 2-3 trys. Im hoping to try and tune that out when i get the chance
but it is a bitch to start now that its cold out, usually takes 2-3 trys. Im hoping to try and tune that out when i get the chance
#11
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af runs about 10.5:0 - 11:1, running about 19 degrees of timing.
Its possible that my second turbo is shot, i went non seq because i couldent get over 7 psi on the secondary. Ive got a single on the way to me right now so i can be done with the twins. Either way its still running the stock intercooler, so i dont think the numbers are too low?
Its possible that my second turbo is shot, i went non seq because i couldent get over 7 psi on the secondary. Ive got a single on the way to me right now so i can be done with the twins. Either way its still running the stock intercooler, so i dont think the numbers are too low?
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Boost creep has nothing to do with having a midpipe/cat. Your catback is the final restriction in your exhaust system and what would more likely deteremine creep. I have a highflow cat and a midpipe. I dont have any boost creep with either. I spike with both though.
I have had 2 sets of turbos and neither one have boost creep. I even put a straight through exhuast and no boost creep. My tests were all done on the 1/4 mile track at Sears Point.
David.
I have had 2 sets of turbos and neither one have boost creep. I even put a straight through exhuast and no boost creep. My tests were all done on the 1/4 mile track at Sears Point.
David.
#13
development
When I had similar mods, the main cat, and stock IC seq. (12-13psi) I was putting down 300wrhp. roughly 40hp diff? Maybe that's the reason for the drop in boost...bad secondary. GO GET'EM SINGLE!!!!
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Originally posted by XSTransAm
40 hp diff? are you lookin at the torque graph? i put down 293
40 hp diff? are you lookin at the torque graph? i put down 293
#19
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Originally posted by ZeroBanger
that 293 was flywheel HP. on a dyno jet you would put about 297 to the wheels.
that 293 was flywheel HP. on a dyno jet you would put about 297 to the wheels.
edit: i just asked my boss why it says flywheel... its cause we can put a tcf value in to correct it to show flywheel hp... but in the case of my car you can plainly see that the tcf (lower right corner) is set to 1.00 which means that it is not using any flywheel correction factor and that is true whp
Last edited by XSTransAm; 12-10-03 at 10:45 AM.
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IC, well the type of dyno you were on was a dyna-pac. As I said earlier a dyna-pac under-reports your hp as it was designed for AWD (its very good for tuning). If you would dyno on a dyno jet your #'s will be around 335. I dynoed at 316 on my previous engine with a MP @ 12 psi.
very good #s anyway.
very good #s anyway.
#21
Rotary Freak
Originally posted by ZeroBanger
Boost creep has nothing to do with having a midpipe/cat. Your catback is the final restriction in your exhaust system and what would more likely deteremine creep. I have a highflow cat and a midpipe. I dont have any boost creep with either. I spike with both though.
Boost creep has nothing to do with having a midpipe/cat. Your catback is the final restriction in your exhaust system and what would more likely deteremine creep. I have a highflow cat and a midpipe. I dont have any boost creep with either. I spike with both though.
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Originally posted by Zoomspeed
Whatever the last component you upgrade in your exhause is going to be the one that determins creep (and the size of your wastegate) so if the last part to be upgraded is the stock cat; then that would determine creep.
Whatever the last component you upgrade in your exhause is going to be the one that determins creep (and the size of your wastegate) so if the last part to be upgraded is the stock cat; then that would determine creep.
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Originally posted by Zoomspeed
Whatever the last component you upgrade in your exhause is going to be the one that determins creep (and the size of your wastegate) so if the last part to be upgraded is the stock cat; then that would determine creep.
Whatever the last component you upgrade in your exhause is going to be the one that determins creep (and the size of your wastegate) so if the last part to be upgraded is the stock cat; then that would determine creep.
Originally posted by ZeroBanger
not true. If your cat back exhaust is restricted you will not get creep. I have an rx7fashion exhaust which is an HKS. I upgraded my highflow cat to a midpipe, no creep.
not true. If your cat back exhaust is restricted you will not get creep. I have an rx7fashion exhaust which is an HKS. I upgraded my highflow cat to a midpipe, no creep.
#24
Rotary Freak
Originally posted by ZeroBanger
not true. If your cat back exhaust is restricted you will not get creep. I have an rx7fashion exhaust which is an HKS. I upgraded my highflow cat to a midpipe, no creep.
not true. If your cat back exhaust is restricted you will not get creep. I have an rx7fashion exhaust which is an HKS. I upgraded my highflow cat to a midpipe, no creep.
For example one could upgrade the CB, then the DP, and then get creep after adding the MP assuming its one of the cars that will get creep. Now if its one of the cars that doesn't get creep then you can go in any order and you still won't get creep.
Sounds like your car is one of the ones that dont' creep (as is mine, lucky for us ). Am I making sense? I havn't slept in a day or 2 and that makes me ramble. lol
#25
Rotary Freak
Originally posted by 911GT2
You guys are arguing the same point, and you're both right. As long as theres one stock piece in the exhaust left, thats what will be holding back flow, and replacing that will determine just how much creep your car is going to have.
You guys are arguing the same point, and you're both right. As long as theres one stock piece in the exhaust left, thats what will be holding back flow, and replacing that will determine just how much creep your car is going to have.