QuickFuel 450 Update and Fix (suggest reading if you have one)
#16
#17
#18
#19
Yeah, with EFI, the max CFM doesn't matter, since it just supplies what it needs. Plus, if you get good, quality injectors, it'll give that precise metering at low RPMs on smaller engines too. Good stuff.
As for the QF 450, I put it to the test this weekend and drove it to my parents house for Christmas (about 300 miles round trip). Gave a nice, steady 14.5 AFR the whole way there and back and about 150% better gas mileage than it was before they fixed it, which is impressive considering that I was driving through a blizzard the whole way there and had the hubs turned and was in and out of 4x4.
So, yeah, it's nice and fixed.
As for the QF 450, I put it to the test this weekend and drove it to my parents house for Christmas (about 300 miles round trip). Gave a nice, steady 14.5 AFR the whole way there and back and about 150% better gas mileage than it was before they fixed it, which is impressive considering that I was driving through a blizzard the whole way there and had the hubs turned and was in and out of 4x4.
So, yeah, it's nice and fixed.
#21
I wasn't able to top it off when I got home like I usually do, but judging from my fuel gauge, I'm down about 20 gallons for 300 miles. So, around 15mpg. Not too shabby considering the hubs were locked the whole time and I was sporadically in and out of 4 wheel drive, and on winter formulated gas.
This summer, before I took the carb off and sent it back to them, I got 9 or 10mpg under much more ideal circumstances. A power valve that doesn't close sure makes a difference.
This summer, before I took the carb off and sent it back to them, I got 9 or 10mpg under much more ideal circumstances. A power valve that doesn't close sure makes a difference.
#22
Not too shabby. What R's are you turning with the 1:1 top gear, 3.00's, and 32's?
By the way, what do you think of the DUI? And is yours running the GM module? Tim Meyer is working with them to get their stuff put in his billet distributor body for the 400, but they seem to be having problems.
By the way, what do you think of the DUI? And is yours running the GM module? Tim Meyer is working with them to get their stuff put in his billet distributor body for the 400, but they seem to be having problems.
#23
80 - 2650
75 - 2500
70 - 2350
65 - 2150
60 - 2000
55 - 1850
I'd love an overdrive, but those RPMs aren't bad at all. I'm very curious what I'll get for MPG when I get the new engine in, and the QF tuned for it. This engine is tired and has around 120 compression in all the cylinders.
As for the DUI, I really like it. It was easy to install and makes for some really snappy performance. The only issue was a module that went bad, but they took care of it for me. The module in it is DUI's version of the GM module.
75 - 2500
70 - 2350
65 - 2150
60 - 2000
55 - 1850
I'd love an overdrive, but those RPMs aren't bad at all. I'm very curious what I'll get for MPG when I get the new engine in, and the QF tuned for it. This engine is tired and has around 120 compression in all the cylinders.
As for the DUI, I really like it. It was easy to install and makes for some really snappy performance. The only issue was a module that went bad, but they took care of it for me. The module in it is DUI's version of the GM module.
#24
#25
I've thought about a ZF, and would love one, but I really don't like their starting gear ratio.
(When not starting out in the low 1st, which is really unnecessary on a daily basis) The NP-435 starts out in a 3.34:1 whereas the ZF is a 2.94. I'd almost always have to start out in it's "granny" gear or I'd be burning my clutch up. Or swap in a 3.50 rear end to compensate, but then I'd basically eat my overdrive up. So... It's not enough to justify the cost/work, so I'm happy with what I have. And my RPMs really aren't much to complain about since I still do have the 3.00.
This is what DUI puts in their system:
GM 4 Pin Dyna-Module - DUI / HEI - Performance Distributors Performance Distributors
(When not starting out in the low 1st, which is really unnecessary on a daily basis) The NP-435 starts out in a 3.34:1 whereas the ZF is a 2.94. I'd almost always have to start out in it's "granny" gear or I'd be burning my clutch up. Or swap in a 3.50 rear end to compensate, but then I'd basically eat my overdrive up. So... It's not enough to justify the cost/work, so I'm happy with what I have. And my RPMs really aren't much to complain about since I still do have the 3.00.
This is what DUI puts in their system:
GM 4 Pin Dyna-Module - DUI / HEI - Performance Distributors Performance Distributors
#26
That's pretty much exactly the rpms I have in OD with mine and 3.73 gears and maybe a 30" tire. It's 245/75/16 I think. Any more gear and it wouldn't accelerate, especially with wind. I get into the enrichment circuit now trying to go 75+ and any wind, especially in any hot weather.
I sure wish I had one of those carbs to "test". The Holly 600 just seems to big for me to tune the secondaries even with the big black spring and just the primaries leave some power on the table. The old Holley 390 I have has issues and I really think it's too small for me to go back and try to work with it. The Edelbrock 500 I have now *seems* decent, but I'm having issues trying to tune the secondaries and it may be from lack of airflow too and it being too big.
I sure wish I had one of those carbs to "test". The Holly 600 just seems to big for me to tune the secondaries even with the big black spring and just the primaries leave some power on the table. The old Holley 390 I have has issues and I really think it's too small for me to go back and try to work with it. The Edelbrock 500 I have now *seems* decent, but I'm having issues trying to tune the secondaries and it may be from lack of airflow too and it being too big.
#27
AB - My 351M with 3.50's had no problem starting in first on the ZF, and I didn't notice a big difference when going from the NP435. However, your RPM's aren't bad at all, so the view might not be worth the climb.
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
GF - Unless you are really winding the 300, which isn't easily done, 500 CFM is a bit much. But, do you have the Performer or the Thunder? The latter can easily be adjusted to open sooner or later, while the former is a huge pain to adjust the opening point.
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
GF - Unless you are really winding the 300, which isn't easily done, 500 CFM is a bit much. But, do you have the Performer or the Thunder? The latter can easily be adjusted to open sooner or later, while the former is a huge pain to adjust the opening point.
#28
AB - My 351M with 3.50's had no problem starting in first on the ZF, and I didn't notice a big difference when going from the NP435. However, your RPM's aren't bad at all, so the view might not be worth the climb.
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
GF - Unless you are really winding the 300, which isn't easily done, 500 CFM is a bit much. But, do you have the Performer or the Thunder? The latter can easily be adjusted to open sooner or later, while the former is a huge pain to adjust the opening point.
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
GF - Unless you are really winding the 300, which isn't easily done, 500 CFM is a bit much. But, do you have the Performer or the Thunder? The latter can easily be adjusted to open sooner or later, while the former is a huge pain to adjust the opening point.
#29
Originally Posted by Gufluh
That's pretty much exactly the rpms I have in OD with mine and 3.73 gears and maybe a 30" tire. It's 245/75/16 I think. Any more gear and it wouldn't accelerate, especially with wind. I get into the enrichment circuit now trying to go 75+ and any wind, especially in any hot weather.
I sure wish I had one of those carbs to "test". The Holly 600 just seems to big for me to tune the secondaries even with the big black spring and just the primaries leave some power on the table. The old Holley 390 I have has issues and I really think it's too small for me to go back and try to work with it. The Edelbrock 500 I have now *seems* decent, but I'm having issues trying to tune the secondaries and it may be from lack of airflow too and it being too big.
I sure wish I had one of those carbs to "test". The Holly 600 just seems to big for me to tune the secondaries even with the big black spring and just the primaries leave some power on the table. The old Holley 390 I have has issues and I really think it's too small for me to go back and try to work with it. The Edelbrock 500 I have now *seems* decent, but I'm having issues trying to tune the secondaries and it may be from lack of airflow too and it being too big.
5.12 * 3.25 = 16.64:1 for his crawl ratio.
I have a 3.00 rear end and a 6.69 1st, so I have a 20.07. Puts it to shame.
From my experience, a 600cfm carb is drivable on a 300. I've had one on there a number of times, and it does surprisingly well. However, you'll just never have that low end snap. I don't think I had any issues getting the secondaries tuned in. It was just a bit higher up in the RPM range (around 3500 - 4000) so I didn't really get into them much.
The 450 QuickFuel is just about the perfect size. Mathematically, the 300 runs out of breath with the 450cfm right around 5200 RPMs, which is plenty. So, the whole carb is used through the whole RPM range. The 500cfm isn't all that much bigger, so unless it's lacking in tunability, it should be a great size too.
I agree that the 390cfm is too small. I tried one for a while and the gas mileage is some of the worst I've dealt with and it always seemed like it was struggling.
AB - My 351M with 3.50's had no problem starting in first on the ZF, and I didn't notice a big difference when going from the NP435. However, your RPM's aren't bad at all, so the view might not be worth the climb.
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
As for the module, that makes sense. Replaces the stock GM module, but you could go back to it if needed. What coil are you running?
3.00 * 3.34 = 10.02:1
3.50 * 2.94 = 10.29:1
However, the ZF with a 3.00 seems like it'd be doggy:
3.00 * 2.94 = 8.82:1
So, I'd probably swap everything out to a 3.50. Front and rear diffs and a ZF swap seems like so much work to drop my RPMs down by 10% seems overkill.
This is the coil that comes with the DUI:
Street/Strip DUI Ignition Coil - Performance Distributors Performance Distributors
Both are DUI's version, but are easily swapped out with generic parts store equivalents should the need arise.