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Enjoy.
"Weekend Racer" Alpine Back running!
- Thread starter spmdr
- Start date
spmdr
Diamond Level Sponsor
I finally finished and tested the Dual Weber DCOE update today.
It took longer than I thought to fit the carbs (custom inter fender brace in the future).
I started with the 151s because they are NOS.
I started with as close as I had to match Alcala's setup.
30mm
125 mains (Alcala 120)
190 air (Alcala 175)
F16
45F4
I ordered 120 mains and 175 air.
It took two test drives to get the carbs in the ball park, set idle speed and sync.
Then another couple of test drives to get the jetting close.
I started with 125 mains and saw the AF go into the 9s and stay there (WFO).
I changed to 120s (and 175 air) and saw the AF go into the 10s and stay there.
I changed to 110s and saw the AF dip into the 12s at lower RPMs and slowly climb to 14 at the top.
Right out of the gate the cruse (3000) was quite stable in the 14s.
There is still a stumble right off idle.
I played with the By-pass screws, briefly. One turn is better than closed (out of the box).
The bottom line is I was hoping the Webers would be a marked change in the Top end.
They are not.
They let the engine pull higher RPMs, but there is clearly a restriction to high RPM power.
I concluded I don't need to take the car to the track until I get it running stronger at the top end.
So with the Weather forecast with highs only in the 50s and possible rain, I decided to pass on the BBB Track event.
I think my next change is a jump to Electronic Ignition, just to make sure that is a not a problem.
And then it's time to go back to the Big valve head.
It took longer than I thought to fit the carbs (custom inter fender brace in the future).
I started with the 151s because they are NOS.
I started with as close as I had to match Alcala's setup.
30mm
125 mains (Alcala 120)
190 air (Alcala 175)
F16
45F4
I ordered 120 mains and 175 air.
It took two test drives to get the carbs in the ball park, set idle speed and sync.
Then another couple of test drives to get the jetting close.
I started with 125 mains and saw the AF go into the 9s and stay there (WFO).
I changed to 120s (and 175 air) and saw the AF go into the 10s and stay there.
I changed to 110s and saw the AF dip into the 12s at lower RPMs and slowly climb to 14 at the top.
Right out of the gate the cruse (3000) was quite stable in the 14s.
There is still a stumble right off idle.
I played with the By-pass screws, briefly. One turn is better than closed (out of the box).
The bottom line is I was hoping the Webers would be a marked change in the Top end.
They are not.
They let the engine pull higher RPMs, but there is clearly a restriction to high RPM power.
I concluded I don't need to take the car to the track until I get it running stronger at the top end.
So with the Weather forecast with highs only in the 50s and possible rain, I decided to pass on the BBB Track event.
I think my next change is a jump to Electronic Ignition, just to make sure that is a not a problem.
And then it's time to go back to the Big valve head.
spmdr
Diamond Level Sponsor
Last Saturday, The WR Alpine was called into service at the CAT Auto-X up in Big Bear CA.
Steve Alcala ran it in the morning and I ran it in the afternoon.
The Webers worked well (not perfect), even at around 6000 ft.
The course was Difficult, Challenging and for some Hopeless.
Once learned, it was entertaining
!
Steve Alcala ran it in the morning and I ran it in the afternoon.
The Webers worked well (not perfect), even at around 6000 ft.
The course was Difficult, Challenging and for some Hopeless.
Once learned, it was entertaining
!
RootesRacer
Donation Time
Not terribly. They dont like much over 2.5psig but will keep a pretty consistent level from 1.5 to 2.5psig
RootesRooter
Gold Level Sponsor
Any other Alpines at the CAT auto-X?
spmdr
Diamond Level Sponsor
When I installed the Webers, I decided to TRY to avoid the problems I have seen with other installations.
- blowing out Carb to manifold O-rings, With floating carbs.
- constantly fiddling with fuel pressure.
So I rigidly mounted the Carbs and didn't install a regulator.
So far, so good, ...I think.
BTW, I'm using a NAPA solid state electric fuel pump.
I DO have to address a Lean hole in the fuel delivery just off idle.
I have not spent any time correcting that yet.
BTDT, Jarrid?
DW
- blowing out Carb to manifold O-rings, With floating carbs.
- constantly fiddling with fuel pressure.
So I rigidly mounted the Carbs and didn't install a regulator.
So far, so good, ...I think.
BTW, I'm using a NAPA solid state electric fuel pump.
I DO have to address a Lean hole in the fuel delivery just off idle.
I have not spent any time correcting that yet.
BTDT, Jarrid?
DW
RootesRacer
Donation Time
I too went to hard mounts this year, also so far so good.
Depending on the throttle position of the lean spot, you might drill another progression hole.
You might also try to get an idle jet just richer than F4. F13 seems to be that jet followed closely by F8.
Just how lean is this spot?
RootesRacer
Donation Time
is it a very small portion of the progression or it is the whole progression area where its lean?
spmdr
Diamond Level Sponsor
I assume the Cruse AFR is mostly set by the Idle jet, and it's quite good in the 14s.
I think my first move is, I suspect, to play with the bypass screws a bit and see if that does the trick.
It does seem to be quite early in the throttle plate movement.
But I'm hesitant to spend much time on it until I get the top end working better.
Because I suspect I would have to redo the whole process then too.
I think my first move is, I suspect, to play with the bypass screws a bit and see if that does the trick.
It does seem to be quite early in the throttle plate movement.
But I'm hesitant to spend much time on it until I get the top end working better.
Because I suspect I would have to redo the whole process then too.
RootesRacer
Donation Time
The top end should be somewhat isolated from the progression except at the transfer between the progression and the mains.
If after sorting out the mains, the required idle jet is the same and the problem still exists (but all other portions of operation are acceptable) I would modify the progression holes or maybe even drill a new hole in the progression where the AFR goes lean.
The progression holes of the 151 is not ideal for small displacement engines and OEM DCOE carbs in this displacement rage usually had 4 or even 5 progression holes.
spmdr
Diamond Level Sponsor
I checked my inventory of spare idle jets only to be reminded the 151s had 60F8 as original.
I also have 50F9s (From the 34-35s).
Seeing I currently have 45F4s, I may plug in the other idle jets and see what I get.
The only other chokes I have are 28s, I think I want to be at 34s.
Currently, power stops in the mid to upper 5000s.
The Webers may have added a few hundred RPMs of power, at most.
But the seat of the pants tells me it pulls better in the mid range,
with the Webers over the Zeniths.
My goal is to get it to pull good power up to 7000 RPM.
Based on the parts it has, it SHOULD be PULLING higher RPMs...
But why isn't it? (rhetorical question...)
I also have 50F9s (From the 34-35s).
Seeing I currently have 45F4s, I may plug in the other idle jets and see what I get.
The only other chokes I have are 28s, I think I want to be at 34s.
Currently, power stops in the mid to upper 5000s.
The Webers may have added a few hundred RPMs of power, at most.
But the seat of the pants tells me it pulls better in the mid range,
with the Webers over the Zeniths.
My goal is to get it to pull good power up to 7000 RPM.
Based on the parts it has, it SHOULD be PULLING higher RPMs...
But why isn't it? (rhetorical question...)
spmdr
Diamond Level Sponsor
I was all ready to bolt the BIG Valve head back on the WR Alpine when I decided to look closer at the head
from a Performance point of view.
If I'm going to compare the stock head, on the engine now, to a modified head,
I want the Moded head to be as good as it can be (within it's current basic specs).
The BIG valve head was the same as when prepared back around 2004, by "The (old) Head guy".
With the valves out, I decided the size of the valve heads compared to minimum inside diameter of the valve seat/pocket
could be improved by making the IDs Bigger.
I went to a very experienced head Guy and he agreed with the mods I wanted to do plus suggested replacing the valves
would be a good idea.
The valves had some ware on the stems and were a Tulip type valve from a V6 Chevy.
He suggested there are ports that benefit from tulip valves but the Alpine ports, not so much.
Of course, back in the day, the valves we used where Not chosen for their shape, more for their size, price and availability.
We talked about future Alpine head projects and what to do, And to my surprise, he was NOT a big Fan of the "Viszard Mod"!
I'm not sure of the reason, my guess is the trade-off with CR. More about that later.
This was the head when fresh in 2004.
from a Performance point of view.
If I'm going to compare the stock head, on the engine now, to a modified head,
I want the Moded head to be as good as it can be (within it's current basic specs).
The BIG valve head was the same as when prepared back around 2004, by "The (old) Head guy".
With the valves out, I decided the size of the valve heads compared to minimum inside diameter of the valve seat/pocket
could be improved by making the IDs Bigger.
I went to a very experienced head Guy and he agreed with the mods I wanted to do plus suggested replacing the valves
would be a good idea.
The valves had some ware on the stems and were a Tulip type valve from a V6 Chevy.
He suggested there are ports that benefit from tulip valves but the Alpine ports, not so much.
Of course, back in the day, the valves we used where Not chosen for their shape, more for their size, price and availability.
We talked about future Alpine head projects and what to do, And to my surprise, he was NOT a big Fan of the "Viszard Mod"!
I'm not sure of the reason, my guess is the trade-off with CR. More about that later.
This was the head when fresh in 2004.
