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rosevillain Samba Member
Joined: December 28, 2005 Posts: 1289 Location: roseville, ca
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Posted: Fri Feb 04, 2011 6:13 pm Post subject: |
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Adriel Rowley wrote: |
[Well, there we have it: 250c.c. per each runner tube and 550c.c., for a total of 1550c.c.. This is interesting for the fact the engine is about 1584c.c..
I did some calculating of cylinder volume. 1600c.c engine is 396c.c., 74mm stroke 1699c.c. engine has a cylinder volume of 425c.c., 76mm stoke 1744c.c. engine has a cylinder volume of 436c.c., the famous 1776c.c. engine has a cylinder volume of 444c.c., and 78.4mm 1779c.c. engine has a cylinder volume of 450c.c.. The intake holds 800c.c of air per a cylinder. This might be the reason up to the 1776 works, as there is enough air to comfortably fill the cylinder and not create high intake air velocity.
The 1776c.c. increases the cylinder volume by 12 percent and 1779c.c. is a 14 percent increase, which to me just be right on the edge of being acceptable, but we probably not going to find out. |
If it's all the same to you guys, I'm going to post all of the FI related info in this thread. Even if this thing falls on it's ass... I know that the help here will be invaluable, and the details may come in handy. |
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Adriel Rowley Samba Member
Joined: October 12, 2006 Posts: 4748 Location: Mesa, Arizona
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Posted: Fri Feb 04, 2011 6:24 pm Post subject: |
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rosevillain wrote: |
Adriel Rowley wrote: |
Well, there we have it: 250c.c. per each runner tube and 550c.c., for a total of 1550c.c.. This is interesting for the fact the engine is about 1584c.c..
I did some calculating of cylinder volume. 1600c.c engine is 396c.c., 74mm stroke 1699c.c. engine has a cylinder volume of 425c.c., 76mm stoke 1744c.c. engine has a cylinder volume of 436c.c., the famous 1776c.c. engine has a cylinder volume of 444c.c., and 78.4mm 1779c.c. engine has a cylinder volume of 450c.c.. The intake holds 800c.c of air per a cylinder. This might be the reason up to the 1776 works, as there is enough air to comfortably fill the cylinder and not create high intake air velocity.
The 1776c.c. increases the cylinder volume by 12 percent and 1779c.c. is a 14 percent increase, which to me just be right on the edge of being acceptable, but we probably not going to find out. |
If it's all the same to you guys, I'm going to post all of the FI related info in this thread. Even if this thing falls on it's ass... I know that the help here will be invaluable, and the details may come in handy. |
Fine by me, as if I do a 76mm stroke engine, it will defiantly be here. I agree, this is the place to show pushing the D-Jetronic as it is not for newbes. _________________ Please consider I am Autistic, so I process information differently and still working on social skills. Thanks.
Dad's 1964 Beetle purchased September 1968.
https://www.thesamba.com/vw/forum/viewtopic.php?p=9252810#9252810
1971 Sunroof Squareback with Fuel Injection
http://www.thesamba.com/vw/forum/viewtopic.php?t=219811&highlight=squareback+rejuvenation |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Fri Feb 04, 2011 7:04 pm Post subject: |
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rosevillain wrote: |
If it's all the same to you guys, I'm going to post all of the FI related info in this thread. Even if this thing falls on it's ass... I know that the help here will be invaluable, and the details may come in handy. |
Thats why the thread is here.
you can be our guinea pig!
Adriel might be on to something with his number calcs -- though where are you getting 800cc per cyl? lets assume that if each runner holds roughly 280 cc, plus 580/4 = 425cc per cyl.
stock cyl volume is 396, and 1776 is roughly 444. that means a 1776 is *JUST* running out of breath with the stock intake. At that size, you probably NEED the extra lift to force ALL the available air from the intake into the cylinder just to meet its basic needs. _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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Adriel Rowley Samba Member
Joined: October 12, 2006 Posts: 4748 Location: Mesa, Arizona
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Posted: Fri Feb 04, 2011 7:54 pm Post subject: |
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JSMskater wrote: |
rosevillain wrote: |
If it's all the same to you guys, I'm going to post all of the FI related info in this thread. Even if this thing falls on it's ass... I know that the help here will be invaluable, and the details may come in handy. |
Thats why the thread is here.
you can be our guinea pig!
Adriel might be on to something with his number calcs -- though where are you getting 800cc per cyl? lets assume that if each runner holds roughly 280 cc, plus 580/4 = 425cc per cyl.
stock cyl volume is 396, and 1776 is roughly 444. that means a 1776 is *JUST* running out of breath with the stock intake. At that size, you probably NEED the extra lift to force ALL the available air from the intake into the cylinder just to meet its basic needs. |
Thank you Joe for the compliment!
What I first did was round the numbers down for margin of error: remember he said he was drinking? Then, as I understand it, the intake valve only opens once. This means the air in the I.A.D. and the air from one runner goes into the engine. So, 250c.c. plus 550c.c. equals 800c.c..
Did all my numbers glaze you over? I stated in there 1776c.c. engine is in fact 444c.c..
With your number of 425c.c., it is interesting to note it is the cylinder volume of a 1699c.c. engine. If you are right about the valves, then this be technically the maximum engine size. _________________ Please consider I am Autistic, so I process information differently and still working on social skills. Thanks.
Dad's 1964 Beetle purchased September 1968.
https://www.thesamba.com/vw/forum/viewtopic.php?p=9252810#9252810
1971 Sunroof Squareback with Fuel Injection
http://www.thesamba.com/vw/forum/viewtopic.php?t=219811&highlight=squareback+rejuvenation |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Fri Feb 04, 2011 8:02 pm Post subject: |
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Ok I see where you got 800 from now, though I think you're forgetting the intakes open on two cylinders at the same time -- so even generously each cyl is only gonna get half of that 550. I think 1/4 is the safe estimate, though if it gets as much as half then you can see where the "wiggle room" comes in, allowing the 1776 to be the max size. _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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Adriel Rowley Samba Member
Joined: October 12, 2006 Posts: 4748 Location: Mesa, Arizona
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Posted: Fri Feb 04, 2011 8:52 pm Post subject: |
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JSMskater wrote: |
Ok I see where you got 800 from now, though I think you're forgetting the intakes open on two cylinders at the same time -- so even generously each cyl is only gonna get half of that 550. I think 1/4 is the safe estimate, though if it gets as much as half then you can see where the "wiggle room" comes in, allowing the 1776 to be the max size. |
I was thinking two intakes open after I posted, so just left it.
So, that would be 250 plus (550c.c./2) which equals 525c.c. and 388c.c. if the I.A.D. air is quartered, which is interesting for the fact a 1584c.c. engine has a cylinder volume of 396c.c.. One could say the middle is safe, which would be 433c.c., or 1744c.c. engine. This then be along the same lines of thought that the 1776c.c. engine is a bit over the maximum for 1600 D-Jetronic.
In the end, we both come out the 1776c.c. engine is the maximum engine for stock type 3 D-Jetronic with stock intake.
This is where we then have to figure out an intake if we were to go larger, though I see no need. But, there might be a way to cut the ends off the stock runner and use 2L I.A.D. and the tubes cut to size. If this worked out, then the only challenge would be cold air intake and possibly a later M.P.S. and fuel injectors.
Sorry about the late night rambling, but maybe some of it will be useful. Very tired so should hit the sack.
Good night you all! _________________ Please consider I am Autistic, so I process information differently and still working on social skills. Thanks.
Dad's 1964 Beetle purchased September 1968.
https://www.thesamba.com/vw/forum/viewtopic.php?p=9252810#9252810
1971 Sunroof Squareback with Fuel Injection
http://www.thesamba.com/vw/forum/viewtopic.php?t=219811&highlight=squareback+rejuvenation |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Fri Feb 04, 2011 9:31 pm Post subject: |
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I think ultimately if you were going to go larger than 1776, you'd have to start using T4 intake parts. IAD and Runners, like you said with the ends cut off and t3 ones welded on -- though at that point I would also have the holes in the head and the feet of the runners opened up and match ported, as I think the step-down to a stock size cross sectional area would restrict flow and increase velocity too much -- but maybe I'm wrong and it'll produce a slight ram air-turbo effect. Something that Ray might know. _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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rosevillain Samba Member
Joined: December 28, 2005 Posts: 1289 Location: roseville, ca
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Posted: Fri Feb 04, 2011 10:08 pm Post subject: |
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JSMskater wrote: |
I think ultimately if you were going to go larger than 1776, you'd have to start using T4 intake parts. IAD and Runners, like you said with the ends cut off and t3 ones welded on -- though at that point I would also have the holes in the head and the feet of the runners opened up and match ported, as I think the step-down to a stock size cross sectional area would restrict flow and increase velocity too much -- but maybe I'm wrong and it'll produce a slight ram air-turbo effect. Something that Ray might know. |
The more I read, the more I believe that that the plenum volume is sized to dampen the vacuum signature. An accumulator of sorts. Runner volume is a factor in this also.
Runners length is determined by cam timing, duration, and desired optimum RPM. When the intake valve shuts, the intake charge bounces off of the shut valve and returns toward the plenum where it hits the high pressure in the plenum, and bounces back toward the valve. If it returns to the valve at the same time that the valve is open, turbo effect coolness.
Intake runner area (diameter), is sized based on the engine displacement, and the required RPM for max torque.
Custom intakes, anyone? |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21510 Location: Oklahoma City
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Posted: Sat Feb 05, 2011 8:48 am Post subject: |
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Bobnotch wrote: |
rosevillain wrote: |
I jumped in with both feet. 1776, stock heads(?), 69mm DPR counterweighted crank.
Found a guy that grinds Porsche cams. He lists a 914 FI cam, much like the Web 107i. Spoke with him on the phone, he's done D-jet engines, and he recommended a custom ground cam close to the specs of his 914 cams, 8.5:1 compression, and ratio rockers if I choose.
Here we go... |
Actually the cam you want him to duplicate the grind for is the Web 86. That grind is a very good replacement grind for FI use in a t-4 engine. I know Ray will cough up the real info on it, but it's a good cam. Even Jake recommends it for FI t-4 engines. |
Avtually the web # 73 (for type 4) is what you want for D-jet. Its intake valve timing is almost identical to the early V code timing of the 411.
A little more lift than what the system was calibrated for is ok...a lot more is not. Excessive lift stalls velocity. Stalling velocity makes for big dips in manifold vacuum....which screws with the MPS.
A little more duration is fine.....as long as it does not screw of the lobe center too far. About 105-106 minimum and about 110 maximum is what these are set up for.
Now.....if you are willing to change the actual injection point timing....a few more things can be done. Its not all that hard...but will take a lot of testing to find the right combination considering the paired injection puts at least two injections quite a ways from ideal valve opening point.
Thats not a real big issue for general running over 2000 rpm....but for idle and throttle transistion, if you get the injection timing too far out....the effect on atomization has quite a large effect on the vacuum signature....which has quite a large effect on the MPS signal.
You can see this for yourself by slotting the screw holes in the trigger point plate. With the engine warmed up and idling normal.....and the fuel pressure gauge hooked up....slide that plate around to change the injection timing point. Not onlt doesit greatly affect idle.....it causes a radical and large swings infuel pressure. This ic caused because the changes it makes to vacuum signature is causing the MPS to bring the pulsewidth to maximum and minimum in an alternating fashion. Ray |
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Bobnotch Samba Member
Joined: July 06, 2003 Posts: 22407 Location: Kimball, Mi
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Posted: Sat Feb 05, 2011 9:34 am Post subject: |
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raygreenwood wrote: |
Avtually the web # 73 (for type 4) is what you want for D-jet. Its intake valve timing is almost identical to the early V code timing of the 411.
A little more lift than what the system was calibrated for is ok...a lot more is not. Excessive lift stalls velocity. Stalling velocity makes for big dips in manifold vacuum....which screws with the MPS.
A little more duration is fine.....as long as it does not screw of the lobe center too far. About 105-106 minimum and about 110 maximum is what these are set up for. Ray |
That's what I get for using my memory. And we know how bad that is. _________________ Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
Tram wrote: |
"Friends are God's way of apologizing for relatives." |
Tram wrote: |
People keep confusing "restored" and "restroyed". |
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rosevillain Samba Member
Joined: December 28, 2005 Posts: 1289 Location: roseville, ca
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Posted: Sat Feb 05, 2011 10:45 am Post subject: |
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My cam will be milder than the Web 73. My displacement will not be 2 liters, though. Trying to optimize the highway RPM and not cause lag off idle.
Ray, would leaving the runner sizing alone (for velocity), and attempting to increase the volume of the plenum help with vacuum signature?
I can imagine a distributor with degree marks, and a slotted trigger plate. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21510 Location: Oklahoma City
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Posted: Sat Feb 05, 2011 2:00 pm Post subject: |
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There are a lot of ways of looking at this.....and I am by no means an expert. I have just looked at, measured and tuned on quite a few systems. As I noted a long time ago just looking at and measuring volumes on lots of succesful engine configurations...not just acvw....tells you a lot about what the factories have found that works.
Runner volume and diameter are important. If the volume gets too low....it becomes either high velocity (not a bad thing in itself because it aids atomization)...but that also makes for high velocity air colums slamming to a halt when the valve shuts. This means that plenum volume and design becomes critical.
If the runner colume gets to high, velocity gets too slow.
The real difficult issue is that when valve sizes go up...the runner diameter shoul;d go up a bit also...but not so far that it creates excessive volume or size transition issues at the port.
In most cases runner volumes are about one cylinder and port volume each. Most runner diameters are right at valve diameter minus a few millimeters for valve stem diameter.
That means at "0' static pressure one runner would be vacuumed dry by the intake stroke. This would be high vaccum like 30" or so. So...the plenum volume needs to be able to readily replenish that runner...and the next one in line and diagonal to it...because you are not fighting just volume needs you are fighting time.
At low to medium rpms, the engine is cyling faster than the air moves from plenum to runner...so the volume must be there to keep vaccum from spiking.
with small displacment changes....you can get away with slightly undersized runners.....but typically you make up for this with slightly upsized plenum...meaning he runners replenish easier and faster so that vaccum does not spike. If you stay with type 3 runners....and therefore stay with type 3 plenum.....I woukld say either machine a "ring" to clamp between the backplate and aluminum bottle...to add volume.....or you could machine the plenum to add a larger TB. If you cant make plenum and runners larger....you need to be able to replenish the plenum faster to keep vacuum down. Going to a larger TB can be problematic for off the line smoothness of throttle transition.
Personally I would enlarge the plenum.
I would think a 1776 would be about the maximum with the stock type 3 runners and plenum. Ray |
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rosevillain Samba Member
Joined: December 28, 2005 Posts: 1289 Location: roseville, ca
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Posted: Sat Feb 05, 2011 4:43 pm Post subject: |
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Thanks, Ray. I was pretty sure that the plenum volume should change.
I had already considered adding a spacer between the cover plate and the housing. I also saw some places in the plenum that are relatively thick, and may be able to be ported.
Also thought about possibly cutting the throttle body snout off, and welding a spacer between the TB and the body. Worst case would be a combination of all three, and machining the snout for a 42mm butterfly. |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Sat Feb 05, 2011 6:10 pm Post subject: |
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rosevillain wrote: |
Thanks, Ray. I was pretty sure that the plenum volume should change.
I had already considered adding a spacer between the cover plate and the housing. I also saw some places in the plenum that are relatively thick, and may be able to be ported.
Also thought about possibly cutting the throttle body snout off, and welding a spacer between the TB and the body. Worst case would be a combination of all three, and machining the snout for a 42mm butterfly. |
what about using a T4 TB and just adapting it to mount? I think the runners would line up the same... _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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rosevillain Samba Member
Joined: December 28, 2005 Posts: 1289 Location: roseville, ca
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Posted: Sat Feb 05, 2011 6:27 pm Post subject: |
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JSMskater wrote: |
rosevillain wrote: |
Thanks, Ray. I was pretty sure that the plenum volume should change.
I had already considered adding a spacer between the cover plate and the housing. I also saw some places in the plenum that are relatively thick, and may be able to be ported.
Also thought about possibly cutting the throttle body snout off, and welding a spacer between the TB and the body. Worst case would be a combination of all three, and machining the snout for a 42mm butterfly. |
what about using a T4 TB and just adapting it to mount? I think the runners would line up the same... |
1600 club rules state that visually, it must remain stock... |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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Posted: Sat Feb 05, 2011 6:55 pm Post subject: |
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rosevillain wrote: |
JSMskater wrote: |
rosevillain wrote: |
Thanks, Ray. I was pretty sure that the plenum volume should change.
I had already considered adding a spacer between the cover plate and the housing. I also saw some places in the plenum that are relatively thick, and may be able to be ported.
Also thought about possibly cutting the throttle body snout off, and welding a spacer between the TB and the body. Worst case would be a combination of all three, and machining the snout for a 42mm butterfly. |
what about using a T4 TB and just adapting it to mount? I think the runners would line up the same... |
1600 club rules state that visually, it must remain stock... |
yeah, cause none of us are gonna notice a clapped out oreo sandwich looking franken-IAD. _________________ 71 Squareback-FI -- 73 Bay (subaru powered)
TOOB Member #3
I make D-jet FI connectors |
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supaninja Samba Member
Joined: July 03, 2010 Posts: 4020 Location: houston
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Bobnotch Samba Member
Joined: July 06, 2003 Posts: 22407 Location: Kimball, Mi
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Posted: Sat Feb 05, 2011 8:15 pm Post subject: |
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Neither of those look STOCK, which is what the poster WANTS. We're still waiting to see YOUR MS work, since that's the new MS thread. Or is Max going to have HIS MS up and running first? _________________ Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
Tram wrote: |
"Friends are God's way of apologizing for relatives." |
Tram wrote: |
People keep confusing "restored" and "restroyed". |
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supaninja Samba Member
Joined: July 03, 2010 Posts: 4020 Location: houston
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Posted: Sat Feb 05, 2011 8:25 pm Post subject: |
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Bobnotch wrote: |
Neither of those look STOCK, which is what the poster WANTS. We're still waiting to see YOUR MS work, since that's the new MS thread. |
I'm still waiting on the heads then i'll have a runner again. Max Weldon is just about to fire up his squirted djet t3. He's going to make a detailed thread about it after its running. That will be the new hotness.
on a side note, my new map sensor is in, just need to build a circuit for it and i'll have continous baro corrections(not usefull here in texas but will be the shizzle at the invasion). I also need to build a curcuit for a tach driver, shift light, and launch control then my MS will be fully hotrodded and ready for the pcb to be conformal coated.
BTW- type 4 stuff won't look stock either _________________ http://i5.photobucket.com/albums/y163/chucky1974/ninja.gif
Nick
Megasquirted Type 4 powered Notch http://www.thesamba.com/vw/forum/viewtopic.php?t=427890&postdays=0&postorder=asc&start=0
Blog of Doom http://supaninjanick.wordpress.com/ |
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JSMskater Samba Grease Gorilla
Joined: February 01, 2006 Posts: 5362 Location: Murrieta California
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