TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
06-17-2003, 08:33 AM
#1
0.5 BAR
Thread Starter
Join Date: Mar 2003
Posts: 116
TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
Hey Guys...
I've completed my D16Z6 rebuild about 3 weeks ago, and I'm using a custom Turbo Cam (for 9PSI), 5-angle valves, a 10:1 FMU, 1 step colder NGK spark plugs, stock injectors, stock pistons and stock rods.
I've been running this setup with an IHI RHB5 turbo for about two weeks now, without any problems, pinging, detonation, etc... The max boost in 5th gear hit 9PSI, but most of the time it was about 7-8 PSI.
Yesterday I've changed an elbow, that goes from the turbo to the IC from a PVC (very restrictive) elbow, to a nice flowing welded elbow... The new elbow is a lot less restrictive, the turbo spools up VERY fast, BUT:
here's the problem...... !
I'm boosting at like 12 PSI max, and an average of 10 - 11 PSI.....
Do you guys think that this might be too much for a stock (but freshly rebuilt) D16Z6 ('95 Si).
The car feels so ------' fast, that it's scary, but I don't wanna blow up the freshly rebuilt motor.
Aha, and I've heard no detonation, even with these HIGH PSI's.
How much boost should I be running?
What would be a safe PSI setting for my motor with the parts that I've mentioned at the top?
How come the elbow made such a HUGE difference in boost? (from 7-9 PSI to 11-12 PSI).
What's the best way to lower the boost on an IHI? (The guy who was rebuilding my turbo suggests putting washers underneath the wastegate, where it connects to the compressor housing. Is that a good way?
Thanks in advance for all the answers.
P.
I've completed my D16Z6 rebuild about 3 weeks ago, and I'm using a custom Turbo Cam (for 9PSI), 5-angle valves, a 10:1 FMU, 1 step colder NGK spark plugs, stock injectors, stock pistons and stock rods.
I've been running this setup with an IHI RHB5 turbo for about two weeks now, without any problems, pinging, detonation, etc... The max boost in 5th gear hit 9PSI, but most of the time it was about 7-8 PSI.
Yesterday I've changed an elbow, that goes from the turbo to the IC from a PVC (very restrictive) elbow, to a nice flowing welded elbow... The new elbow is a lot less restrictive, the turbo spools up VERY fast, BUT:
here's the problem...... !
I'm boosting at like 12 PSI max, and an average of 10 - 11 PSI.....
Do you guys think that this might be too much for a stock (but freshly rebuilt) D16Z6 ('95 Si).
The car feels so ------' fast, that it's scary, but I don't wanna blow up the freshly rebuilt motor.
Aha, and I've heard no detonation, even with these HIGH PSI's.
How much boost should I be running?
What would be a safe PSI setting for my motor with the parts that I've mentioned at the top?
How come the elbow made such a HUGE difference in boost? (from 7-9 PSI to 11-12 PSI).
What's the best way to lower the boost on an IHI? (The guy who was rebuilding my turbo suggests putting washers underneath the wastegate, where it connects to the compressor housing. Is that a good way?
Thanks in advance for all the answers.
P.
06-17-2003, 09:13 AM
#2
0.5 BAR
Join Date: Feb 2003
Posts: 170
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
as long as you are not leaning out, 10 psi is fine. a local guy up here has a boosted d16y8 running 10 psi and a little over 200 HP to the wheels. you should be fine at 10...12 is really pushing it. use a bleeder valve to control that boost
06-17-2003, 09:23 AM
#3
1.5 BAR
Join Date: Feb 2003
Posts: 702
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
A bleeder vavle will increase the boost. As long as you have enough fuel the 12psi should also be ok. You looking at 120psi fuel pressure at that level and its not going to be long till the pump or injectors start to have problems.
06-17-2003, 10:09 AM
#5
1.5 BAR
Join Date: Feb 2003
Posts: 702
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
a bleeder valve goes in the line to the wastegate actuator. it bleeds the boost pressure off so that the wastegate opens later.. This increases the boost. you can get all the parts at homedepot for about $7
06-17-2003, 10:41 AM
#6
0.5 BAR
Thread Starter
Join Date: Mar 2003
Posts: 116
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
OK, so a bleeder valve INCREASES boost...
What should I do to DECREASE boost?
(can this be done with a bleeder valve?)
or... Do I have to take off the turbo off the mani, and modify the wastegate actuator arm? (Is there any better/simpler/faster way of modifying the boost setting on an IHI RHB5?)
What should I do to DECREASE boost?
(can this be done with a bleeder valve?)
or... Do I have to take off the turbo off the mani, and modify the wastegate actuator arm? (Is there any better/simpler/faster way of modifying the boost setting on an IHI RHB5?)
06-17-2003, 11:59 AM
#8
0.5 BAR
Thread Starter
Join Date: Mar 2003
Posts: 116
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
How much do I have to shorten it by (approximately) to land in the 8 PSI range?
Do you know of a place where I can find pics of a "modified" wastegate actuator arm (instead of a shitty-*** diagram in the NEWBIE FAQ's...? (I wanna see what parts I need to get in order to lenghten/adjust it...)
Does anybody know exactly what parts I need to get in order to do this?
(IS 12 PSI too much?)
Do you know of a place where I can find pics of a "modified" wastegate actuator arm (instead of a shitty-*** diagram in the NEWBIE FAQ's...? (I wanna see what parts I need to get in order to lenghten/adjust it...)
Does anybody know exactly what parts I need to get in order to do this?
(IS 12 PSI too much?)
06-17-2003, 12:25 PM
#9
1.5 BAR
Join Date: Feb 2003
Posts: 702
Re:TOO MUCH BOOST? (On my D16Z6 with IHI RHB5)
I don't think 12 psi is too much with a good fuel system.. it is a little high with an fmu.
www.denverspeed.com has a good write up on the actuator rods. I think you need to make it longer. doesn't it push the wastegate flapper open?
www.denverspeed.com has a good write up on the actuator rods. I think you need to make it longer. doesn't it push the wastegate flapper open?
