Boost falling off

vrracing · 05-08-2012, 11:28 AM

Yup. Car runs fine as 12psi of boost. The helper spring was the key piece. Havent messed with it since.

Last week the top plastic radiator endcap cracked and was leaking so he installed a Godspeed aluminum rad with a GM shrouded electric fan. Really opened up the engine bay and the polished rad looks really good. It was in the 90s and muggy as Houston here and it cooled very nicely using a Flex-A-Lite thermoswitch to control the fan.

At the same time the kid put a Corksport turbo intake duct as a purely prophylactic measure. Nice piece.

88turboii · 05-08-2012, 04:56 PM

i have an extra spring on my S5 hybrid too. another problem ive discovered, if you are running the factory turbine wheel, it can cause so much back pressure that it will open the wastegate by itself. the extra spring helps keep it closed until the actuator wants it open. that could have been happening, especially at high rpm. and ive never heard of running too rich that it limits boost, unless its actually misfiring

vrracing · 05-08-2012, 05:25 PM

Yeah, Bryan @ BNR said the adjustable w/g rod didnt really do much.

Sharingan 19 · 05-08-2012, 08:48 PM

Quote:

Originally Posted by vrracing

Yeah, Bryan @ BNR said the adjustable w/g rod didnt really do much.

In your particular case, or as a general rule? Seems kinda of silly to offer an "upgrade" that doesn't work...

10thanniv · 05-08-2012, 09:45 PM

I had same issue, lacking boost (6psi) with BNR stage3. I have the adjustable wastegate, which I had to pay for and was set to 12 psi from BNR. I looked for boost leaks for a couple of weeks and couldn't find any. I adjusted the wastegate rod and the boost went up to 7 psi. I finally installed my MBC and got it up to 11psi. Running good now, but wasted money on the adjustable wastegate.

vrracing · 05-09-2012, 10:58 AM

Quote:

Originally Posted by Sharingan 19

In your particular case, or as a general rule? Seems kinda of silly to offer an "upgrade" that doesn't work...

Bryan forgot to do the adjustable rod on mine (it is supposed to be part of a Stage1 so I didnt pay extra for it) and I asked him how he made the mod. He told me "I cut the rod, weld a coupling nut on it. Then thread the rod end and adjust it that way. Only around a 2-3 additional psi is all you can get out of it"

So he may be doing it as a bonus so someone can get a couple extra psi over stock. I think it might be better to fit an adjustable helper spring mechanism that would better match to typical goals instead.

Quote:

Originally Posted by 10thanniv

I finally installed my MBC and got it up to 11psi. Running good now, but wasted money on the adjustable wastegate.

Our HKS EBC and the unaided WG actuator couldn't keep the WG closed so we had to add the helper spring.

Sharingan 19 · 05-10-2012, 02:11 PM

Interesting...

I too have an HKS ECV (EVC 1 actually) and it seemed to have no problem keeping the wg closed to the tune of 15+ psi, however I very rarely (if ever) took the car to redline, so perhaps thats why I never noticed a problem?

vrracing · 05-11-2012, 10:44 AM

Before the helper spring we would peak at 9.9 @ 4600 and then drop to 7 by 6000 as can be seen in my first post with the graph.

I assume BNR doesnt replace the WG so boost is controlled by a 20 year old spring that has gone thru many heat cycles. It seems reasonable to assume that different springs will degrade at different rates.

I doubt that the version of EVC matters. This one is a Black Edition but I've never been able to figure out which normal edition that maps to. It only displays in kpa but since we use the Zeitronix for monitoring boost it doesnt matter.

05-08-2012, 11:28 AM	#31
vrracing Rotating Assembly Join Date: Oct 2008 Location: TX iTrader: (0) Posts: 102 Rep Power: 17	Yup. Car runs fine as 12psi of boost. The helper spring was the key piece. Havent messed with it since. Last week the top plastic radiator endcap cracked and was leaking so he installed a Godspeed aluminum rad with a GM shrouded electric fan. Really opened up the engine bay and the polished rad looks really good. It was in the 90s and muggy as Houston here and it cooled very nicely using a Flex-A-Lite thermoswitch to control the fan. At the same time the kid put a Corksport turbo intake duct as a purely prophylactic measure. Nice piece. __________________ 90 S5 Vert. JDM Tii with BNR Stage1 turbo. Pineapple Racing street port. Bonez cat-forward. Corksport cat-back with Vibrant UltraQuiet resonator. RTek 2 wZeitronix w/b. HKS EBC. Vis CF Tii hood. 3000GT wing. Ground Control coilover kit with KYB AGX shocks. Red and Black leather RX8 seats. Corksport Odura lip & bumper caps, OEM Tii skirts

05-08-2012, 04:56 PM	#32
88turboii destroy, rebuild, repeat Join Date: Feb 2008 Location: Charleston, SC iTrader: (0) Posts: 395 Rep Power: 17	i have an extra spring on my S5 hybrid too. another problem ive discovered, if you are running the factory turbine wheel, it can cause so much back pressure that it will open the wastegate by itself. the extra spring helps keep it closed until the actuator wants it open. that could have been happening, especially at high rpm. and ive never heard of running too rich that it limits boost, unless its actually misfiring __________________ 1993 RX-7 Touring MB, stockport 13B-REW, 9.4CR rotors, T04S 60-1/p-trim single turbo 1986 RX-7 Base project track beast Last edited by 88turboii; 05-08-2012 at 04:59 PM..

05-08-2012, 05:25 PM	#33
vrracing Rotating Assembly Join Date: Oct 2008 Location: TX iTrader: (0) Posts: 102 Rep Power: 17	Yeah, Bryan @ BNR said the adjustable w/g rod didnt really do much. __________________ 90 S5 Vert. JDM Tii with BNR Stage1 turbo. Pineapple Racing street port. Bonez cat-forward. Corksport cat-back with Vibrant UltraQuiet resonator. RTek 2 wZeitronix w/b. HKS EBC. Vis CF Tii hood. 3000GT wing. Ground Control coilover kit with KYB AGX shocks. Red and Black leather RX8 seats. Corksport Odura lip & bumper caps, OEM Tii skirts

05-08-2012, 09:45 PM	#35
10thanniv Weekend fun Join Date: Feb 2012 iTrader: (0) Posts: 6 Rep Power: 0	I had same issue, lacking boost (6psi) with BNR stage3. I have the adjustable wastegate, which I had to pay for and was set to 12 psi from BNR. I looked for boost leaks for a couple of weeks and couldn't find any. I adjusted the wastegate rod and the boost went up to 7 psi. I finally installed my MBC and got it up to 11psi. Running good now, but wasted money on the adjustable wastegate. __________________ 1982 RX7 172,000miles Sold 1984 RX7 GSL-SE 237,000miles Sold 1994 SHO Sold 1997 GTP Sold 2000 Xtrerra 4x4 Sold 1988 RX7 10thAE 69000 Weekend Fun 2015 CX-5 DD

05-11-2012, 10:44 AM	#38
vrracing Rotating Assembly Join Date: Oct 2008 Location: TX iTrader: (0) Posts: 102 Rep Power: 17	Before the helper spring we would peak at 9.9 @ 4600 and then drop to 7 by 6000 as can be seen in my first post with the graph. I assume BNR doesnt replace the WG so boost is controlled by a 20 year old spring that has gone thru many heat cycles. It seems reasonable to assume that different springs will degrade at different rates. I doubt that the version of EVC matters. This one is a Black Edition but I've never been able to figure out which normal edition that maps to. It only displays in kpa but since we use the Zeitronix for monitoring boost it doesnt matter. __________________ 90 S5 Vert. JDM Tii with BNR Stage1 turbo. Pineapple Racing street port. Bonez cat-forward. Corksport cat-back with Vibrant UltraQuiet resonator. RTek 2 wZeitronix w/b. HKS EBC. Vis CF Tii hood. 3000GT wing. Ground Control coilover kit with KYB AGX shocks. Red and Black leather RX8 seats. Corksport Odura lip & bumper caps, OEM Tii skirts

05-10-2012, 02:11 PM	#37
Sharingan 19 Rotary Fanatic Join Date: May 2010 iTrader: (0) Posts: 138 Rep Power: 15	Interesting... I too have an HKS ECV (EVC 1 actually) and it seemed to have no problem keeping the wg closed to the tune of 15+ psi, however I very rarely (if ever) took the car to redline, so perhaps thats why I never noticed a problem?