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-   -   Hard pipes w/filters causing too much boost!?!? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/hard-pipes-w-filters-causing-too-much-boost-261590/)

White94RX 01-17-04 09:36 AM

Hard pipes w/filters causing too much boost!?!?
 
I got my hard intake pipes off E-bay. I bought two cone filters for them. I got everything installed and put back together, and went for a drive. When I gassed it, the boost went up to 12 or 13 psi! My only other engine mod is a downpipe. I didn't think I'd be experiencing any overboost or creep unless I had a cat-back and/or midpipe.

What's the deal? Why am I getting boost creep or spike or whatever if I only have the intake and downpipe? If I remove the filters and put on the stock airbox with the hard pipes, would this fix the problem?

Do I have to get a boost controller to run the hard pipes with cone filters?

artguy 01-17-04 10:25 AM

you should not be boosting more than ten lbs with the stock restrictor pills in the lines. if you have to, put on the home depot manual boost controller setup and turn the boost all the way down...slowly adjust it until you get the boost back to ten lbs and then adjust the prespool til you get a decent kick in the pants on the first turbo.

what a great time to lose that stock intercooler which is killing your turbos and coolant seals...throw in a fuel pump..injectors...catback...and a powerfc/tuning..should probably do the radiator too....ooooh...and dual oil coolers....gosh...so much love left for your baby.

BAM good to go!

David Beale 01-17-04 10:40 AM

If it settles at some number below 14 PSI, that isn't "boost creep". Boost creep is the system loosing control of the boost limit as RPMs increase. The boost doesn't settle at 12 or 13 (or any other number), it keeps rising until physically limited by turbo output. Caused by the wastegate being overloaded.

In your case it's just the control system not able to work properly. I doubt 12 or 13 PSI will harm the engine with the stock ECU. My understanding is it can handle (fuelwise) up to 14 PSI. You have freed up the intake, so yes, you will see higher boost. Just adjust the pills to compensate. Contrary to some opinion the intake often has a greater effect on this than the exhaust (intercooler, cold air intake, and hose replacement).

It may just be that it's cold outside, and with cold ambient air we all see higher boost.

BoostCrzy 01-17-04 11:12 AM

take the wastegate pill out of the line and you should see a decrease in max boost....

patriick 01-17-04 11:22 AM

Re: Hard pipes w/filters causing too much boost!?!?
 

Originally posted by White94RX
I got my hard intake pipes off E-bay. I bought two cone filters for them....
Be sure to install a heat-shield so that the intakes suck in cold outside air instead of the hot air in the engine compartment. This is especially important since the hot air also has the effect of reducing the intercooler's efficiency (especially the stock one).

Check Robinette's site (here) for a write-up on the manual boost controller.

Mahjik 01-17-04 11:23 AM

Re: Hard pipes w/filters causing too much boost!?!?
 

Originally posted by White94RX
Do I have to get a boost controller to run the hard pipes with cone filters?
Yes, just do it right and get a boost controller.

Less restrictive intake and cool weather = boost spikes

If you must go cheap, at least use the ball and spring type valves, not the bleeder valves. The bleeder valves will slow turbo response.

jupiter 01-17-04 01:35 PM

I'be been having the same problem. Just intake and exhaust. And my boost spikes up to 14 when I gun it.
I guess more toys are in order...

cruiser 01-17-04 02:20 PM

New toys or new engine - your pick ;)

White94RX 01-17-04 08:08 PM

I forgot to mention I am running the poor man's non-sequential mod.

As for the restrictor pills, would I just take a slightly larger drill bit and open up the hole? Do this with the pre-control too? What happens if I go too large, low boost?

Tim Benton 01-17-04 11:14 PM

Russ, poor man's non seq. on the stock ECU?

Tim

Quickfini 01-17-04 11:52 PM

I actually have a downpipe, aluminum hard intake pipes w/ K&N filters and heatshield, Blitz catback, and the Efini Y-pipe with the restrictor pills, and i'm at about 11-8-11 or so.

I tried adjusting it down with the manual boost controllers, but they would just make it go UP to 14-15psi instead. I couldn't get them tuned right, so I just took them out completely.

patriick 01-18-04 01:43 AM


Originally posted by Quickfini
...I tried adjusting it down with the manual boost controllers, but they would just make it go UP to 14-15psi instead.
Sounds like you might have left the pill in wastegate actuator line. The idea is to remove the pill and replace it with an adjustable valve.

More restriction in the line (pill + valve?) = less pressure on the actuator's diaphram = WG opens less = more exhaust energy to spin the turbines = more boost

White94RX 01-18-04 05:25 PM

Yeah, I'm still using the stock ECU.

bee 01-18-04 06:12 PM

Dont listen to them. Its not ok to boost that high on the stock ecu. Go get a needle valve and some vacume hose and replace the line running to your wastegate with a new line having the needle valve in the center. Open it all the way and drive the car around, boost should be somewhere around 9-10 lbs. Closing the valve will cause boost to go higher. Just remember, left = low (boost). Search for Rob Robinette on google. His site has a great write up on the manual boost controller. Dont worry about the prespool line though, just get the one for the wastegate. The other is useless unless you are using the controller to controll high boost. Which your not, because of the stock ecu.

Quickfini 01-18-04 08:01 PM


Originally posted by patriick
Sounds like you might have left the pill in wastegate actuator line. The idea is to remove the pill and replace it with an adjustable valve.

More restriction in the line (pill + valve?) = less pressure on the actuator's diaphram = WG opens less = more exhaust energy to spin the turbines = more boost

Yeah that's exactly what I did haha. I took out the stock pills and replaced them with valves from Home Depot. I still could not get them tuned right.

patriick 01-18-04 08:47 PM


Originally posted by bee
... Search for Rob Robinette on google. His site has a great write up on the manual boost controller...
No need, I posted a link in my post above ;)

Tim Benton 01-19-04 07:24 AM

how good of a good does the stock ecu do when you've went non seq? it doesn't kick back any error codes or anything?

Tim

TwinTurbo93 01-19-04 09:29 AM


Originally posted by White94RX
I forgot to mention I am running the poor man's non-sequential mod.

As for the restrictor pills, would I just take a slightly larger drill bit and open up the hole? Do this with the pre-control too? What happens if I go too large, low boost?

If you're running non-seq. you don't need the pre control, cap it, and the wastegate control remove the hose with the pill and se what's gonna happen, it should not boost more than 7psi so you should be able to adjust easyly after with a HD boost controler starting from wide open and closing 1/4 turn at the time little by little as you test the boost.

racerfoo 01-19-04 12:43 PM

Stock ECU and poormans non-seq throws no codes.....poormans non-seq only removes a few things and caps a few hoses. It is when you start removing solenoids and all that when you see error codes.

RX7UP 01-19-04 01:08 PM


Originally posted by Quickfini
I actually have a downpipe, aluminum hard intake pipes w/ K&N filters and heatshield, Blitz catback, and the Efini Y-pipe with the restrictor pills, and i'm at about 11-8-11 or so.

I tried adjusting it down with the manual boost controllers, but they would just make it go UP to 14-15psi instead. I couldn't get them tuned right, so I just took them out completely.

Are you selling anything you pulled out? PM me....


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