help me on this debate boost creep is bad for.....
 

ok before anyone yells at me for being a noob see my point and tell me what you think!

i have had hondas in the passed and i came to a real sports car! and now i was talking to some buddys and we where talking about boost creep. now he was telling me that boost creep is bad for the motor, which i can agree with, but the problem is if you have a stock top mount intercooler your will never get that boost creep to the motor. now how do i come up with that? easy the stock top mount intercooler can handle at max 12 psi and it doesn't hold that much until red line. now i was saying that boost creep is bad for the turbo if you have a stock turbo and a stock tmic. because if the wastegate is too small. all it is going to do is over heat instead of letting the extra flow out the wastegate. am i right about that? let me get your feed back and input on this! now the only reason why i say i had a honda is because we had a civic in the car club and he would suffer from boost creep because of the spot where his wastegate was so it was spike but it never reached his motor because he had a dsm smic and it can only hold like 10-12 psi. his gauge would shoot up to 14 psi at times. so he switched some vaccum hoses and he noticed that it never went past 8psi. so that is why i say boost creep is more damage for a stock turbo with a stock intercooler am i right?

boost creep has nothing to do with the intercooler...
It's all based on the wastegate. The stock top mount intercooler is efficient until 12 PSI...it won't stop boost at 12....

If your wastegate is too small and you have an unrestricted exhaust, you will have boost creep....no ifs ands or buts...

The only way to counter the boost creep problem is by porting the wastegate.

The intercooler will hold as much pressure as the welds or the couplers, there's no way for the pressure to escape. Boost creep is bad if your car isn't capable of running at that boost. (Which the stock car isn't capable of doing at 12-14 psi)

the stock turbo CAN blow 19psi worth of air
is it hot air that is worthless and bad for turbo? yes
but can it do it
yes

so me saying that boost creep is just as bad for a turbo is not valid? that is what the debate was about he was saying that boost creep can not do any damage to the turbo! i was saying that it will over heat and blow the interals of the turbo

Not unless it's overspinning the turbo. It's all relative. Such as, how MUCH it creeps, how much the turbo can flow, etc. If the stock turbo creeps from 8psi to 12psi, it won't harm it at all. If it creeps from 8psi to 20psi, well, it ain't good!

ok now leads me to ask how this all got started! my FC is all stock but the rebuild was done with a street port set up and it has an intake and a turbo back exhaust so he was telling me that i will boost creep to 20 psi now and that is how we got into the whole wastegate and stuff, but i find it impossible for it to creep all the way up to 20 psi! maybe 10 what do you think?

With a full exhaust and intake, and running the wastegate directly, i'd expect creep to around 12-15psi, it varies. It's not all too hard to port the wastegate though.

yeah your talking to someone that is not ready to change the injectors yet alone port a wastegate!...lol i am going to send it out in the spring for a stage one set up so i can get it ported that way!

If you hit 20psi with the stock turbo and the stock ECU, you are going to damage something.


-Ted

I had an unrestricted exhaust and I didn't have any boost creep. All cars are different. How's that but for you?

What do you call an "unrestricted exhaust"?
Even a 3" is slightly restrictive.
Anything 3.5" / 4.0" or larger is what I would "unrestrictive". :)

Also, do you own a Zenki or a Kouki turbo?
It does make a difference...


-Ted

I had stock S4 turbo.

Ask him, i thought he ment not utilizing the stock cats as "unrestricted." A full turbo back system would be "unrestrictive" to most of us on the forum, or so I thought. Don't know many who have a 3.5" or 4" turbo back system.

I don't know. Im not Japanese. Ask me in english and I can answer you.

Zenki is the S4.
Kouki is the S5.

Well, rather, Zenki means 'early model', and Kouki is 'late model', or something like that, there's a lot of cars that use those terms.

Technically something like that.... :)

When it comes to boost creep, all S4's are the same. If you had an unported wastegate and an "unrestricted" exhaust, and you had no boost creep, then something was broken.

i agree about the English though...

fcs rule-

unless you want to go killing that new motor, port the wastegate, get a FCD, and start building up a fuel system (EMS or RTEK/piggybay, injectors, pump, etc.) that will support higher boost levels. Check out FC3Spro.com and the "mild to wild" section for step by step modifications required for higher horsepower levels than stock. Search for NZconvertibles wastegate porting how-to on here. Like I said, you don't want to go killing that motor.........

I knew someone would tell me that it was broken. :)
You know, I was boosting 8psi for about a year no boost creep, working twin scroll. Then swapped in some 680cc inj. a Walbro and ran the stock s4 turbo at 10 psi, (turning it up with a MBC) for another year. No creep. What would have to break to cause me to be able to consistently run 8 and then 10psi with no creep? And with no other side affects other than no boost creep?

I say, all cars are different! Even with the same turbo. Take into account we all use different after market parts. I had a full turbo back HKS system. Maybe my turbo is worn out, or maybe his is. Bottom line, that turbo I had on there (never rebuilt) is now on another car, boosting 12psi for track purposes, while his turbo gets an upgrade. I dunno how that poor little turbo is still alive. And he boost creeps to 14psi, haha. Very rarely but I've seen it happen. Most cars will boost creep, because of the wg, very true, but not every single rx7 that ever got a full "unrestricted*" exhaust will. All im saying.

:)


Happy Holloween to all. :devil:


*Unrestricted: 2.5" inch or 3" turbo back system with no cats.

I can only hazard a guess that all that extra fuel kept the boost creep at bay...


-Ted

yeah if your running too rich it wont make as much power and wont spin the turbo as fast to cause as much creep

i have a 88 vert with a tii swap, it was like that when i bought it....now...the question is how would i know if he swapped a Zenki TII or Kouki TII. What are the signs?

You think at 10psi with 680cc secondaries that its way to much fuel? Hmm... Well I thought I needed them, but not before I installed the S-afc II and dyno tuned that badboy. Turns out it was just about right and didn't really need any adjustments. But I smoothed out my a/f line and gained 8hp after tuning. :bigthumb: I didn't mention all of that because we were talking about creep and I wanted to stay on topic. Have no fear my rex is well taken care of :)

Why would running rich keep the boost down? I didn't think it would affect boost. Has no one else had a car that didnt boost creep? Am I alone?


At 8psi I did not have the 680cc's or the Walbro. Still no creep.

i agree with you there, mine doesnt creep at 8psi either, at 75% throttle. you metioned a dyno, what numbers did you get, with those mods you should support over 200rwhp. im suprised nobody has mentioned rotor compression. simple physics, even 85-90 psi per rotor will not allow boost creep to develop until like 10k rpm in 1st-2nd gear! if you wot in 5th, you have to get boost creep. its just not possible, really man. im not trying to gang up on you with everyone... the only other thing i can think of is it already is ported and you dont know. or loose throttle cable, things of this nature.

to the guy who wrote the thread, sorry we bombed it. for you i really think some reading is nessasary. start from scratch, learn how a turbo system works, then branch from there. millions of write ups around, youll have to look though. from the way you ask things, its sounds like your friends read half a paragraph then go smoke a hoobie or something :) come back to this thread in a year and read what you said. youll laugh! trust me, i did with mine!

ok, your prob, think about it, your fuel management is a computer that has a set fuel ratio to deliver. when you alter the motor, you cannot change the fuel ratio to compensate. so, you are effectively running lean(not enough gas, too much air) you can do 2 things to combat this, stay stock, or port the wg(wastegate) and get a mbc(manual boost controller). also think of this, middle of winter and you have heavy clothes on. you can do work but its rather difficult, yet you dont really need extra water. now, middle of summer and you have t-shirt and shorts on. its easier to move, you can get more work done, but you are more thirsty. same deal with the motor. dont touch it and its fine, soon as you mod it to make it run faster, it needs supporting mods like gatorade :)

Ok, ok , let me give my Japanese a wurl. Although this has nothing to do with creep. You want to know if your vert was swapped with an earlier model TII Rx-7 or if he swapped your vert with a later model TII rx7? Well, just go outside and look at it, fast way is do you have round lights?:rofl: Although he could have changed them, check to see if you have a little 1/4 pie boost gauge in the left corner of your cluster... :rofl: j/k, lets everyone calm down! Ok, sorry about that, my Japanese needs some work.

I will assume you mean TII motor and not the whole car. Or do you mean S4 and S5 turbo since this is about boost creep? Hmm...that question seems to require a long answer, and many ifs and's or but's. He could have swapped over stuff from both or everything from just one. There are many signs to look for on many of the parts, to know what was used from what series car. Since you can see the car and don't know what's what, I suggest you start a thread and post some pics, as the explanations between parts from both cars will require long answers with details on the "signs" to see what part was used in your swap.
Other than that, since you have a S4, my guesstemate would be that he took the easier route and used a S4 motor ECU and harness. You would have to pick out all the other parts and identify them separately. Easy way, just ask him. ;)