The Twin Screw Thread
#166
Bill,
I would would swear you are describing my car exactly! I can also hear a slight difference in the exaust and not quite as smooth as before. I think the computer is working hard trying to main the 14.7 air/fuel ratio.
Please don't forget me on the throttle upgrade.
Thanks
I would would swear you are describing my car exactly! I can also hear a slight difference in the exaust and not quite as smooth as before. I think the computer is working hard trying to main the 14.7 air/fuel ratio.
Please don't forget me on the throttle upgrade.
Thanks
#167
Daryl:
I've posted before that I do have a persistent IDLE roughness when the car heats up. It has been traced to a drop-out of cyl 7 ONLY AT IDLE. Once off idle, cyl 7 fires normally. I have had this since immediately after the SC install and have not found the cause. The car dynos and drives perfectly OK otherwise and has had 10K miles of care-free driving under all kinds of conditions including 100s of miles in the desert almost flat out. So, someday I will probably find a heat-expanding gap somewhere. I am going to get into this when I install the intercooler sometime this winter. Until then I just drive it daily. It's outside here at work waiting for me to drive the 40 mile trip home tonight. Guess I should get back to work for a while....
I've posted before that I do have a persistent IDLE roughness when the car heats up. It has been traced to a drop-out of cyl 7 ONLY AT IDLE. Once off idle, cyl 7 fires normally. I have had this since immediately after the SC install and have not found the cause. The car dynos and drives perfectly OK otherwise and has had 10K miles of care-free driving under all kinds of conditions including 100s of miles in the desert almost flat out. So, someday I will probably find a heat-expanding gap somewhere. I am going to get into this when I install the intercooler sometime this winter. Until then I just drive it daily. It's outside here at work waiting for me to drive the 40 mile trip home tonight. Guess I should get back to work for a while....
#168
Originally Posted by BrianG
Speaking of resealing the manifold............
I got my manifold from Andy preassembled with the intercooler, and powdercoated. Should I dis-assemble it and re-seal the 1/2's before the install?
I got my manifold from Andy preassembled with the intercooler, and powdercoated. Should I dis-assemble it and re-seal the 1/2's before the install?
Just because its pre assembled doesn’t mean its sealed. The best way ive found is to run some masking tape around the perimeter of the seem leaving appx 1/4 inch of the seam exposed. Then take some sealant...i used "The Rightstuff" and apply a light, thin bead of it along the entire seam. then take your finger (wear a latex glove or something) and smear the bead flat and smooth..filling in any gaps or question able areas.
Once done, remove the tape and your left with a really nice neat bead of sealant along the entire perimeter.
With the nice red manifold you have you want to keep it as neat looking as possible!
Looks great!
#170
Originally Posted by Shane
Warren the first v-belt groove on the pulley from Andy is for the A/C belt. It looks like the pulley you have is a two piece design, similar to the stock pullies.
The one I have for the whipple is a one piece design that has a v-belt for the A/C and the rest are ribbed belts. It also comes wth replacement pulley for the power steering pump. I did not have one for the smog pump since I was not using it. HTH
The one I have for the whipple is a one piece design that has a v-belt for the A/C and the rest are ribbed belts. It also comes wth replacement pulley for the power steering pump. I did not have one for the smog pump since I was not using it. HTH
#171
Originally Posted by mspiegle
Your first question:
From the looks of what you have, the largest circular pulley is for the AC (IIRC), and the smaller ribbed pulley bolted to it is for the SC. Now, my question is if you can take the stock pulley, place it inside the center of the SC pulley, and bolt the whole thing up as 1 piece. Does that make sense? I'm thinking if he mentioned something about blocking the smog pump, that's because when you put the stock pulley inside of the SC pulley - the SC pulley will block the rib used for the smog pump. Does that make any sense? This is ALL speculation. I have never seen that pulley design before, and haven't specifically asked Andy about it... but its the only thing that makes sense to me at the moment.
Your second question:
The "normal" pullies (blue anodized ones that most of us got) work on both the autorotor and jag/eaton superchargers. I assume the pulley you have will work the same as well.
From the looks of what you have, the largest circular pulley is for the AC (IIRC), and the smaller ribbed pulley bolted to it is for the SC. Now, my question is if you can take the stock pulley, place it inside the center of the SC pulley, and bolt the whole thing up as 1 piece. Does that make sense? I'm thinking if he mentioned something about blocking the smog pump, that's because when you put the stock pulley inside of the SC pulley - the SC pulley will block the rib used for the smog pump. Does that make any sense? This is ALL speculation. I have never seen that pulley design before, and haven't specifically asked Andy about it... but its the only thing that makes sense to me at the moment.
Your second question:
The "normal" pullies (blue anodized ones that most of us got) work on both the autorotor and jag/eaton superchargers. I assume the pulley you have will work the same as well.
#173
Bill,
I forgot to mention that when my car is cold it runs perfectly, only after it warms up does the slight roughness start.
Geeez, did you have to mention that you get to go for a 40 mile drive in your car today?? I suppose the temperature is about 70s?
Here is what I am looking at out my front door right now!
I forgot to mention that when my car is cold it runs perfectly, only after it warms up does the slight roughness start.
Geeez, did you have to mention that you get to go for a 40 mile drive in your car today?? I suppose the temperature is about 70s?
Here is what I am looking at out my front door right now!
#174
When you pull the vac line off the BEGI you should also pull it off the fuel reg as well to get a true reading.
FWIW, the needle valve will have minimal effect with out the restrictor on the manifold signal line to the BEGI unit
On that note...how many of the TwinScrew set ups are currently using the restrictor in the signal line?
Now that ive figured it out (i think) i dont know how you could NOT use it. It made a HUGE difference in the needle valve adjustment (final fuel pressure under boost)
I would leave the needle valve closed and use the BEGI onset adjustment to tune where you want your final fuel pressure to be when you are in boost.
What is the differnce between a VORTCH FMU and the BEGI unit then?
dont they do the same thing?
Also..the 8:1 ratio...i assume that is above a stock value?
ie: 5psi boost is in acrease of 40psi fule pressure at that level over stock.
Why is the value it 8:1?
#175
Originally Posted by Daryl
Bill,
I forgot to mention that when my car is cold it runs perfectly, only after it warms up does the slight roughness start.
I forgot to mention that when my car is cold it runs perfectly, only after it warms up does the slight roughness start.
#177
Wow. With all the resealing Tony did, if he has it, then there is something systemic. Mine is very clearly a cylinder 7 miss. When the miss starts, it is a stumble at idle in gear at stoplights. It is worse in park or neutral - a virtual complete drop of cylinder 7. You can hear it in the tail pipe and the car shakes mildly. If I pull the spark boot and/or the injector lead to 7, there is no change at all, whereas all the other cylinders show a response to a pulled lead. Swapped injectors, new plugs, wires, etc. It's always cylinder 7. Hit the gas - no problem. I keep thinking something is leaning out #7 at idle when warm - perhaps related to the bypass passage which is nearest 7. I have not gotten any further with this. As I said, the car runs so well under any kind of power, only stumbling at idle, that I have not pursued it vigorously, especially since it's such a stumper with no clear cause.
#178
Daryl:
Looks like a warm day for Saskatoon in December. When I was single I had a brief fling with a girl from Saskatoon and went to visit her one April. April, you know the month when things generally are blooming around most parts of the world? Jesus HC! I thought we had returned to the ice age! It was truly glacial weather. It was the first time I had seen these things you mount on the inside of your car door windows so you can have any hope of seeing out of them in the subzero high for the day. I'm still shivering.
Looks like a warm day for Saskatoon in December. When I was single I had a brief fling with a girl from Saskatoon and went to visit her one April. April, you know the month when things generally are blooming around most parts of the world? Jesus HC! I thought we had returned to the ice age! It was truly glacial weather. It was the first time I had seen these things you mount on the inside of your car door windows so you can have any hope of seeing out of them in the subzero high for the day. I'm still shivering.
#179
Originally Posted by Tony
<snip>
Also..the 8:1 ratio...i assume that is above a stock value?
ie: 5psi boost is in acrease of 40psi fule pressure at that level over stock.
Why is the value it 8:1?
Also..the 8:1 ratio...i assume that is above a stock value?
ie: 5psi boost is in acrease of 40psi fule pressure at that level over stock.
Why is the value it 8:1?
I'm way ignorant on these voodoo fuel pressure regulator devices, but it may have something to do with the relationship between fuel injector inlet pressure difference and fuel injector flow difference. The flow through the injector isn't linear with relation to a pressure change to the injector. IIRC, it's something like the square root of the pressure ratio. Going from 40 lbs to 44 lbs = 44/40 = 1.1 ratio in pressure. Sq. root of 1.1 is 1.0488. in this case a 10% increase in fuel pressure gets less than 5% increase in fuel flow. That's why fuel pressure has to increase more than air pressure. Even then it's logarithmic, not a straight multiplication like 8:1.
#180
Originally Posted by Tony
The best way ive found is to run some masking tape around the perimeter of the seem leaving appx 1/4 inch of the seam exposed. Then take some sealant...i used "The Rightstuff" and apply a light, thin bead of it along the entire seam. then take your finger (wear a latex glove or something) and smear the bead flat and smooth..filling in any gaps or question able areas.
Once done, remove the tape and your left with a really nice neat bead of sealant along the entire perimeter.
Once done, remove the tape and your left with a really nice neat bead of sealant along the entire perimeter.