Boost spikes !!
#1
Boost spikes !!
OK I have a straight pipe On my fd and I get boost spikes like 17 ps .. Can I control them with the power fc or get like a normal boost controller ? Thanks
#2
no...
probably need a boost controller..not to mention porting your wastegate...
try a search on this subject..you may find you can try changing pill size and such, but I dont think that will work..
probably need a boost controller..not to mention porting your wastegate...
try a search on this subject..you may find you can try changing pill size and such, but I dont think that will work..
#3
Senior Member
Joined: Dec 2001
Posts: 334
Likes: 0
From: Crestview, FL
I put a downpipe and a catback on my car and was getting similar boost spikes. I think that you should be able to control it by using pills. Even though I don't have a straightpipe I think the principle is the same. You can find more info about changing the pills at this website.
http://www.scuderiaciriani.com/rx7/how-to_turbos.html
I would suggest that you buy the Holley Carb (which contains several different size jets) and get several feet of fuel line hose (I think that is the correct type). What you might want to do is take the hoses off with the pills (wrap tape around them and label them so you know which one goes where) and then replace them with hoses without any pills at all. If you are still getting boost spikes, then changing the pills won't do you any good. You should be getting around 8 psi or so without any pills. If that is around what you get then proceed with adjusting the pills.
When I adjusted my pills I started at a high numbered holley jet (around 84) and then jumped down around 5 jet sizes so that I could pinpoint the correct pill size faster. I would also recommend that you keep the size difference which was set by the factory. By this I mean that the Wastegate (shorter hose) should be 5 sizes larger than the Precontrol (longer hose). I think the stock orifice sizes are as follows:
Pre-control (longer hose) .059"
Wastegate (shorter hose) .064"
These roughly correspond to pill 64 and 59 from Holley. See the website I listed above for more info. I hope I helped at least a little bit.
http://www.scuderiaciriani.com/rx7/how-to_turbos.html
I would suggest that you buy the Holley Carb (which contains several different size jets) and get several feet of fuel line hose (I think that is the correct type). What you might want to do is take the hoses off with the pills (wrap tape around them and label them so you know which one goes where) and then replace them with hoses without any pills at all. If you are still getting boost spikes, then changing the pills won't do you any good. You should be getting around 8 psi or so without any pills. If that is around what you get then proceed with adjusting the pills.
When I adjusted my pills I started at a high numbered holley jet (around 84) and then jumped down around 5 jet sizes so that I could pinpoint the correct pill size faster. I would also recommend that you keep the size difference which was set by the factory. By this I mean that the Wastegate (shorter hose) should be 5 sizes larger than the Precontrol (longer hose). I think the stock orifice sizes are as follows:
Pre-control (longer hose) .059"
Wastegate (shorter hose) .064"
These roughly correspond to pill 64 and 59 from Holley. See the website I listed above for more info. I hope I helped at least a little bit.
#6
The boost controller will not control your boost creep/spike. The PFC worked for me for a little while, but now I have some boost creep. I have hit 17 psi and I'm still surprised that my engine is running extremely strong. The best thing to do is get the wastegate ported, upgrade your ECU and upgrade your fuel system. Also, do a search on the forum, this has been discussed many times, good luck.
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#8
Senior Member
Joined: Dec 2001
Posts: 334
Likes: 0
From: Crestview, FL
Have you figured out the problem yet? Did changing the pills help or have you had a chance to try them? Just checking on your progress. It took me a little over a month to figure out the problem with my boost (I had to adjust the pills, replace a solenoid and a check valve. Let me know how things are coming along. Maybe I can help.
#9
Originally posted by VTAOE
Have you figured out the problem yet? Did changing the pills help or have you had a chance to try them? Just checking on your progress. It took me a little over a month to figure out the problem with my boost (I had to adjust the pills, replace a solenoid and a check valve. Let me know how things are coming along. Maybe I can help.
Have you figured out the problem yet? Did changing the pills help or have you had a chance to try them? Just checking on your progress. It took me a little over a month to figure out the problem with my boost (I had to adjust the pills, replace a solenoid and a check valve. Let me know how things are coming along. Maybe I can help.
#11
You may also be getting the higher boost spikes because of the cold weather. I've noticed on the few warmer days we had this winter, my spikes weren't as bad. I may try the Home depot solution as soon as I get some good silicon tubing.
#14
A PFC will likely not fix the problem if you are seriously spiking over 15 psi. The stock fuel pump and injectors cannot supply enough fuel for that much boost. You are seriously risking running very lean on the spikes. This is one of the cons of installing a midpipe. A boost controller (or Home Depot method) may not help enough either because your wastegate is simply getting overwhelmed and can't vent enough air. If your attempts to reduce the spike don't work, you should seriously consider going with a high-flow cat instead of a midpipe.
#16
I have the same problem but it is not as high. I am thinking of setting up my AVC-R too see if it helps to lower the boost spike. It went to abit over 15 then back. I noticed this when I was running on dyno, and here is my chart I don't know why it is not a smooth cruve, can anyone help me out?
Dyno sheet
Dyno sheet
Last edited by rerx7; 03-22-02 at 09:03 PM.
#17
Originally posted by rerx7
I have the same problem but it is not as high. I am thinking of setting up my AVC-R too see if it helps to lower the boost spike. It went to abit over 15 then back. I noticed this when I was running on dyno, and here is my chart I don't know why it is not a smooth cruve, can anyone help me out?
Dyno sheet
I have the same problem but it is not as high. I am thinking of setting up my AVC-R too see if it helps to lower the boost spike. It went to abit over 15 then back. I noticed this when I was running on dyno, and here is my chart I don't know why it is not a smooth cruve, can anyone help me out?
Dyno sheet
#18
Damn, I just noticed that you're running an intake, downpipe, midpipe, and exhaust and you don't have an ecu! You need an ecu now. That HKS fuel stuff is not enough. You should also upgrade your intercooler and fuel pump.
With those mods you should be making more than 275 rwhp.
With those mods you should be making more than 275 rwhp.
Last edited by rynberg; 03-23-02 at 12:40 AM.
#21
Originally posted by Ef-Dee
will somebody please tell me what a boost spike is??????!!!
will somebody please tell me what a boost spike is??????!!!
Last edited by RecKleSs; 04-04-02 at 12:09 PM.
#23
Originally posted by Ef-Dee
how do you tell that you have a boost spike then?
how do you tell that you have a boost spike then?
#25
Originally posted by to_slow
Do you think the new blitz boost controler will help a bit? well thanks again ..!
Do you think the new blitz boost controler will help a bit? well thanks again ..!
I was hoping the blitz boost controller will help me a little bit with the boost creep, however, there was no change at all in boost creep.