newb question
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wHiTe kNiGhT
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From: ct
newb question
ok guys i know this has been asked and told many times, but i couldnt find anythin on the search...so here it is
wut is the difference between creep and spike? i know that creep is when the exhaust cant get out fast enough, and i think spike is caused when the 2nd turbo kicks in or somthin along thos lines? plz help me out on this one. plz plz dont give me any stupid ****, im still learning and i dont wanna hear it from pple who are gonna be dicks about it...thanx
geoff
wut is the difference between creep and spike? i know that creep is when the exhaust cant get out fast enough, and i think spike is caused when the 2nd turbo kicks in or somthin along thos lines? plz help me out on this one. plz plz dont give me any stupid ****, im still learning and i dont wanna hear it from pple who are gonna be dicks about it...thanx
geoff
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From: Los Angeles
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From: cromwell,CT
spike is transition from 1st turbo to second creep is when you let off the throttle at high rpms and the boost creeps up to a higher psi because of a less restricted exhaust and of the small size of the stock wastegate. am i right
I know spike can be prevented by putting a manuel valve between the precontrol acuator and turbo but i'm worried about getting creep. I will have dp,mp,cb (M2 dual) and apexi intakes with a profectic B boost controller and apexi power fc. How bad will i get creep ?? Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
I know spike can be prevented by putting a manuel valve between the precontrol acuator and turbo but i'm worried about getting creep. I will have dp,mp,cb (M2 dual) and apexi intakes with a profectic B boost controller and apexi power fc. How bad will i get creep ?? Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
Originally posted by af908
Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
https://www.rx7club.com/forum/showth...ht=boost+creep
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wHiTe kNiGhT
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From: ct
Originally posted by af908
spike is transition from 1st turbo to second creep is when you let off the throttle at high rpms and the boost creeps up to a higher psi because of a less restricted exhaust and of the small size of the stock wastegate. am i right
I know spike can be prevented by putting a manuel valve between the precontrol acuator and turbo but i'm worried about getting creep. I will have dp,mp,cb (M2 dual) and apexi intakes with a profectic B boost controller and apexi power fc. How bad will i get creep ?? Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
spike is transition from 1st turbo to second creep is when you let off the throttle at high rpms and the boost creeps up to a higher psi because of a less restricted exhaust and of the small size of the stock wastegate. am i right
I know spike can be prevented by putting a manuel valve between the precontrol acuator and turbo but i'm worried about getting creep. I will have dp,mp,cb (M2 dual) and apexi intakes with a profectic B boost controller and apexi power fc. How bad will i get creep ?? Will going non sequential help to stop creep? I know this has been discussed but i can't seem to find a straight answer.
hmm thats a good one can anyone help us
heh
geoff
Boost spike (someone correct me) is the pre-spool allowing too much boost. This can usually be adjusted using a decent boost controller or the Home Depot valves.
Boost creep is the wastegate being overrun and unable to handle the amount of flow. This typically happens when the exhaust is opened up too much (i.e. adding a midpipe). Usually a hi-flo cat has enough restriction to keep boost creep from happening. However, if you experience boost creep your only options are typically to add restriction to the exhaust (something like restriction plates) or to port the wastegate.
Boost creep is the wastegate being overrun and unable to handle the amount of flow. This typically happens when the exhaust is opened up too much (i.e. adding a midpipe). Usually a hi-flo cat has enough restriction to keep boost creep from happening. However, if you experience boost creep your only options are typically to add restriction to the exhaust (something like restriction plates) or to port the wastegate.
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wHiTe kNiGhT
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From: ct
Originally posted by af908
Will going non sequential help to stop creep?...
Will going non sequential help to stop creep?...
i wanna know...by puttin a hfc then ur losing horse power. so how can u take away creep and still be able to run stright pipes and not have to port waste gate?
Originally posted by rx7raca
i wanna know...by puttin a hfc then ur losing horse power. so how can u take away creep and still be able to run stright pipes and not have to port waste gate?
i wanna know...by puttin a hfc then ur losing horse power. so how can u take away creep and still be able to run stright pipes and not have to port waste gate?
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From: west palm beach, FL
boost spike is the turbo spooling faster than the wastegate actuator can open the wastegate.....creep is the wastegate not being able to bypass enough exhaust to control the spool....usually spike is reduced by increasing the volume of air reaching the wastegate actuator....creep is reduced by using a wastegate with a large enough flow capacity to limit the amount of exhaust that reaches the turbo.....
Originally posted by BoostCrzy
mahjik, u can also stop the creep by restricting the intake......
mahjik, u can also stop the creep by restricting the intake......
However, not all FD's experience boost creep (even with midpipes), so there is never a single solution for every car.
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From: cromwell,CT
Originally posted by BoostCrzy
yea...its usally a combination of variables involved......
yea...its usally a combination of variables involved......
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From: cromwell,CT
Originally posted by BoostCrzy
boost spike is the turbo spooling faster than the wastegate actuator can open the wastegate.....creep is the wastegate not being able to bypass enough exhaust to control the spool....usually spike is reduced by increasing the volume of air reaching the wastegate actuator....creep is reduced by using a wastegate with a large enough flow capacity to limit the amount of exhaust that reaches the turbo.....
boost spike is the turbo spooling faster than the wastegate actuator can open the wastegate.....creep is the wastegate not being able to bypass enough exhaust to control the spool....usually spike is reduced by increasing the volume of air reaching the wastegate actuator....creep is reduced by using a wastegate with a large enough flow capacity to limit the amount of exhaust that reaches the turbo.....
Originally posted by af908
what variables do you mean? Would an ecu like the power fc and a good boost controler like the profec B help?
what variables do you mean? Would an ecu like the power fc and a good boost controler like the profec B help?
Originally posted by the_saint
The creep is present because of too much flow through the turbos despite the wastegate being told by the ECU/boost controller to be 100% open.
You will not have boost creep problems unless you are running a full 3 inch exhaust (DP/MP[with or without resonator]/CB). Adding some restriction such as a hi-flow cat, or a more restrictive catback exhaust, or a restrictor plate in the exhaust flow can help.
A restrictor plate is just a gasket (made of metal) that has a hole that is smaller than the internal diameter of the exhaust piping. For example, having a hole of only 2 inches.
You can place it between the DP/MP, or between the MP/CB. I am not sure of the best location. I ran a plate between the DP and MP. As the gases get further from the exhaust manifold they will cool and become denser. You can also run silencers in your exhaust if you have for example the Apex'i GT or N1, or N1 Duals.
The plates are easy to make if you have the right tools, or you can have them machined by a shop. I had a bunch made up when I just wanted one, but now they are all accounted for.
Hope that helps.
Ulimately, the best thing is to port the wastegates. . But with the plates you can keep the boost down to a reasonable level, (depending on how free flowing your exhaust is, how good your turbos are, and the size of the hole, 10-14 psi [ I tried a bunch of different sizes] but you will need the fuel to compensate for the increased boost.) This is not an issue if you are tuned for 14 psi and run 14 psi max.
The Borla XR-1 is a silencer/resonator. I have it welded in the middle of my MP. It has 3 inch inlet and outlet, is a straight through design, with perforated core, and sound absorbing material inside that is apparently able to withstand the hi temps of rotaries. They are about $125 from summit racing, and my exhaust shop charged about $20 USD to weld it in.
The creep is present because of too much flow through the turbos despite the wastegate being told by the ECU/boost controller to be 100% open.
You will not have boost creep problems unless you are running a full 3 inch exhaust (DP/MP[with or without resonator]/CB). Adding some restriction such as a hi-flow cat, or a more restrictive catback exhaust, or a restrictor plate in the exhaust flow can help.
A restrictor plate is just a gasket (made of metal) that has a hole that is smaller than the internal diameter of the exhaust piping. For example, having a hole of only 2 inches.
You can place it between the DP/MP, or between the MP/CB. I am not sure of the best location. I ran a plate between the DP and MP. As the gases get further from the exhaust manifold they will cool and become denser. You can also run silencers in your exhaust if you have for example the Apex'i GT or N1, or N1 Duals.
The plates are easy to make if you have the right tools, or you can have them machined by a shop. I had a bunch made up when I just wanted one, but now they are all accounted for.
Hope that helps.
Ulimately, the best thing is to port the wastegates. . But with the plates you can keep the boost down to a reasonable level, (depending on how free flowing your exhaust is, how good your turbos are, and the size of the hole, 10-14 psi [ I tried a bunch of different sizes] but you will need the fuel to compensate for the increased boost.) This is not an issue if you are tuned for 14 psi and run 14 psi max.
The Borla XR-1 is a silencer/resonator. I have it welded in the middle of my MP. It has 3 inch inlet and outlet, is a straight through design, with perforated core, and sound absorbing material inside that is apparently able to withstand the hi temps of rotaries. They are about $125 from summit racing, and my exhaust shop charged about $20 USD to weld it in.
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From: cromwell,CT
Originally posted by Mahjik
Ulimately, the best thing is to port the wastegates. . But with the plates you can keep the boost down to a reasonable level, (depending on how free flowing your exhaust is, how good your turbos are, and the size of the hole, 10-14 psi [ I tried a bunch of different sizes] but you will need the fuel to compensate for the increased boost.) This is not an issue if you are tuned for 14 psi and run 14 psi max.
Ulimately, the best thing is to port the wastegates. . But with the plates you can keep the boost down to a reasonable level, (depending on how free flowing your exhaust is, how good your turbos are, and the size of the hole, 10-14 psi [ I tried a bunch of different sizes] but you will need the fuel to compensate for the increased boost.) This is not an issue if you are tuned for 14 psi and run 14 psi max.
I understand everything except this....is this saying that if i tune to 14psi i will get no creep?
Another thing i noticed is that 94's dont seem to get creep as bad as 93s. is there something different 94s have that 93s dont?
will going non-seqential help at all with creep? I know it helped Don't Be a Rikki. Because he says he now has zero creep after going non seq. Has going non-seq helped anyone else out with boost creep issues?
Originally posted by af908
I understand everything except this....is this saying that if i tune to 14psi i will get no creep?
Another thing i noticed is that 94's dont seem to get creep as bad as 93s. is there something different 94s have that 93s dont?
will going non-seqential help at all with creep? I know it helped Don't Be a Rikki. Because he says he now has zero creep after going non seq. Has going non-seq helped anyone else out with boost creep issues?
I understand everything except this....is this saying that if i tune to 14psi i will get no creep?
Another thing i noticed is that 94's dont seem to get creep as bad as 93s. is there something different 94s have that 93s dont?
will going non-seqential help at all with creep? I know it helped Don't Be a Rikki. Because he says he now has zero creep after going non seq. Has going non-seq helped anyone else out with boost creep issues?
93's and 94's are basically the same. I've seen no correlation to boost creep and 93's only (not that there isn't any, I've just never seen it).
Boost creep means that the boost will creep to a certain level (whether it's 14 PSI, 15, 17 or whatever) no matter what. It's not necessarily "14 PSI". the_saint was using that as an example. If you are tuned for what your boost is creeping to, then it's not really an issue, however you still have problem as the boost could creep higher.
If you read the_saint's message, you'll see that if your wastegate is already open at 100% and it's still not enough to stop the creep, then there is nothing that can be done but port the wastegate (to allow more air) or add some restriction to the exhaust (to reduce some air flow).
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