FMU modification
#21
Supporting Vendor
Thread Starter
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
man, on the dyno I could make Brad run at 60psi or 120psi at 12psi, with the tiniest little turn of the ****.
Are you running a restrictor on the vacuum line?
when you described what Corky said to do I was thinking this (see image)
But it makes sense to just open up the breather line to help relieve more pressure out of the fmu so the needle valve can work more effiecently.
Are you running a restrictor on the vacuum line?
when you described what Corky said to do I was thinking this (see image)
But it makes sense to just open up the breather line to help relieve more pressure out of the fmu so the needle valve can work more effiecently.
Your image is still a concept I will explore if necessary. It would ramp up pressure quickly until the point where the second path opens, then continue to raise pressure, but at a slower rate.
#22
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
yeah.
no seriously, without a restrictor I could barely adjust the pressures anything less than a 10:1 rise. the restrictor gives you a hell of a lot more adjustability, and like corky said, you plain can't bleed off enough.
no seriously, without a restrictor I could barely adjust the pressures anything less than a 10:1 rise. the restrictor gives you a hell of a lot more adjustability, and like corky said, you plain can't bleed off enough.
#25
Supporting Vendor
Thread Starter
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
Success
Restrictor and double check valve ftmfw. Look good to you guys?
(quick street tune between office and house)
(quick street tune between office and house)
__________________
91 Turbo | 10AE Turbo | 01 Track Rat | #323 Mazda Champcar
Chief of Floor Sweeping, DIYAutoTune.com & AMP EFI
Crew Chief, Car Owner & Least Valuable Driver, HongNorrthRacing
Last edited by Ben; 01-03-2007 at 05:54 PM.
#27
Supporting Vendor
Thread Starter
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
yes, it's actually a little richer in the middle and a good bit leaner at the top. my setup is completely the same since i went to the dyno last month. i might be crazy, but i think i saw 10psi on the boost gauge. it's been a solid max 9 psi for the past month, and i haven't touched the mbc. the car is definately more responsive.
the log i posted was the result of 3 or 4 street pulls. compare that to the log from the dyno which was the result of an hour of tuning.
the log i posted was the result of 3 or 4 street pulls. compare that to the log from the dyno which was the result of an hour of tuning.
#28
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Got mine setup...i think I'll try to dual check valves as I don't think I'm bleeding off enough....
Seems to be smoother and holds out as the fuel dumps in, hopefully i can fine tune it a little more....
Seems to be smoother and holds out as the fuel dumps in, hopefully i can fine tune it a little more....
#29
Supporting Vendor
Thread Starter
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
That's pretty good. Here's something to try, might work a little better than where you are now :
Run a 8:1 vortec disc and put a ball n spring mbc between the needle valve and check valve. Set the check valve to open after peak torque. That way the needle won't actually bleed until when it starts going towards 10:1. Hopefully at that point, the needle starts to vent, and slows the rate of rise at higher boost. Should hold a flatter a/f curve that what you showed. If the 8:1 is a little agressive, try the 6:1.
This doesn't accomplish turning the vortec into a afpr, per say. But it allows bleed to slow the rate of rise after a certain point. Between that, and choosing the proper disc, it should give a lot more flexibility... and ultimately, more hp and flatter tq.
Run a 8:1 vortec disc and put a ball n spring mbc between the needle valve and check valve. Set the check valve to open after peak torque. That way the needle won't actually bleed until when it starts going towards 10:1. Hopefully at that point, the needle starts to vent, and slows the rate of rise at higher boost. Should hold a flatter a/f curve that what you showed. If the 8:1 is a little agressive, try the 6:1.
This doesn't accomplish turning the vortec into a afpr, per say. But it allows bleed to slow the rate of rise after a certain point. Between that, and choosing the proper disc, it should give a lot more flexibility... and ultimately, more hp and flatter tq.
Thread
Thread Starter
Forum
Replies
Last Post
FAB
Prefabbed Turbo Kits
216
03-22-2017 04:00 PM
expensivehobby22
Prefabbed Turbo Kits
65
02-06-2007 08:31 PM