Fun with needles
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Re: Fun with needles
I am somewhat skeptical that you were actually running 18.5 or 19 to one at 80 MPH. At least not smoothly. At those AFR ratios would expect a lot of hesitation, bucking and probable and lean misfire. Spark plugs would come out dead white. Not saying it isn't possible9 Smooth running at Super lean mixtures ) ... just not likely on an L series engine.
I suspect you may have an instrumentation error. A wise Engine builder taught me a Golden rule many years ago. Instrumentation can lie. If the engine performance does not correlate with what the Instruments say... double check the Instruments. At 80 mph the engine is into the Power Fuel curve going to require around 12.5 to 13 to 1 AFR at the leanest to run right. It will run at 15 to 1...maybe even 16 to 1. But 18.5 to 19 to 1? That engine should not be happy and should be giving you some warning signs.
Only the latest Direct fire engine with super trick combustion chambers can run mixture that lean at those speeds . An L-series should be bucking and spitting and probably detonating like a SOB at those mixtures. Steady mixtures that is. As lean spike for a moment is quite common and can be tuned out. But a steady 18.5 or 19 to 1 at speed? No way, without some other signs of engine distress.
Things that can make a O2 sensor read wrong.
1: Incorrect calibration. There are still some WB O2 sensors for sale that still require an Initial and periodic air calibration. Most of the old Innovate WB gauges were that way. Read the instructions carefully for your WB to see if Calibration is required. The newer UEGO WB Bosch sensors ( Bosch LSU 4.2 or 4.9 sensor ) as used by AEM are self calibrating, which is nice. But not all manufacturers use self calibrating UEGO sensors. That makes a big difference.
2: Any exhaust leak, but particularly those ahead of the O2 sensor, will cause a false reading.
3: As O2 sensors age, they get less accurate. They can also be ruined by overheating, Leaded gas of course ( or Lead substitutes ) and by certain types of Silicone RTV sealers. Silicon RTV sealers mustbe labelled as O2 Sensor safe. And that includes any sealers exposed to the Intake manifold, Exhaust manifold, Engine block, Oil pan, Valve cover or anything short of the Water passages. Gassing off from a Silicone sealer on an Oil pan gasket can contaminate an O2 sensor in fairly short order. Contaminated silicone gasses are pulled through PCV system, into the Intake manifold and out the exhaust. Silicone sprays for assembly intake coupling or hoses can also contaminate O2 sensors, although the out gassing is much shorter.
Personally I would put a fresh set of plugs in. Go for a Cruise at 70 to 80 MPH and then do a quick plug check. The plugs won't lie. Dip the clutch, kill the engine and pull off with out idling ( In a safe place of course ). Then pull the plugs and take a high resolution picture of all of the plug firing ends. Use a good Digital Camera ( no cell phone Camera's unless they are the lastst UBER Phones ) and make sure that the flash is turned off. Flash alters the color spectrum and makes plug reading useless. Then post up the pictures of the plugs here. Make and model of plug required of course ( assuming standard NGK BPR-6ES for your car)
Cruise for a while carefully watching your temperatures and listening for any pinging or detonation. If you hear any pinging STOP!!!! Add a couple few more flats of fuel enrichment with the SU needle adjusting nuts and maybe back off ignition timing. You do NOT want to break rings or melt a piston.
BTW, what is your ignition timing set to out of curiosity? Idle setting and total mechanical advance ( Vacuum advance disconnected for testing )
I suspect you may have an instrumentation error. A wise Engine builder taught me a Golden rule many years ago. Instrumentation can lie. If the engine performance does not correlate with what the Instruments say... double check the Instruments. At 80 mph the engine is into the Power Fuel curve going to require around 12.5 to 13 to 1 AFR at the leanest to run right. It will run at 15 to 1...maybe even 16 to 1. But 18.5 to 19 to 1? That engine should not be happy and should be giving you some warning signs.
Only the latest Direct fire engine with super trick combustion chambers can run mixture that lean at those speeds . An L-series should be bucking and spitting and probably detonating like a SOB at those mixtures. Steady mixtures that is. As lean spike for a moment is quite common and can be tuned out. But a steady 18.5 or 19 to 1 at speed? No way, without some other signs of engine distress.
Things that can make a O2 sensor read wrong.
1: Incorrect calibration. There are still some WB O2 sensors for sale that still require an Initial and periodic air calibration. Most of the old Innovate WB gauges were that way. Read the instructions carefully for your WB to see if Calibration is required. The newer UEGO WB Bosch sensors ( Bosch LSU 4.2 or 4.9 sensor ) as used by AEM are self calibrating, which is nice. But not all manufacturers use self calibrating UEGO sensors. That makes a big difference.
2: Any exhaust leak, but particularly those ahead of the O2 sensor, will cause a false reading.
3: As O2 sensors age, they get less accurate. They can also be ruined by overheating, Leaded gas of course ( or Lead substitutes ) and by certain types of Silicone RTV sealers. Silicon RTV sealers mustbe labelled as O2 Sensor safe. And that includes any sealers exposed to the Intake manifold, Exhaust manifold, Engine block, Oil pan, Valve cover or anything short of the Water passages. Gassing off from a Silicone sealer on an Oil pan gasket can contaminate an O2 sensor in fairly short order. Contaminated silicone gasses are pulled through PCV system, into the Intake manifold and out the exhaust. Silicone sprays for assembly intake coupling or hoses can also contaminate O2 sensors, although the out gassing is much shorter.
Personally I would put a fresh set of plugs in. Go for a Cruise at 70 to 80 MPH and then do a quick plug check. The plugs won't lie. Dip the clutch, kill the engine and pull off with out idling ( In a safe place of course ). Then pull the plugs and take a high resolution picture of all of the plug firing ends. Use a good Digital Camera ( no cell phone Camera's unless they are the lastst UBER Phones ) and make sure that the flash is turned off. Flash alters the color spectrum and makes plug reading useless. Then post up the pictures of the plugs here. Make and model of plug required of course ( assuming standard NGK BPR-6ES for your car)
Cruise for a while carefully watching your temperatures and listening for any pinging or detonation. If you hear any pinging STOP!!!! Add a couple few more flats of fuel enrichment with the SU needle adjusting nuts and maybe back off ignition timing. You do NOT want to break rings or melt a piston.
BTW, what is your ignition timing set to out of curiosity? Idle setting and total mechanical advance ( Vacuum advance disconnected for testing )
Last edited by Chickenman on 01 Oct 2015 16:33, edited 1 time in total.
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Re: Fun with needles
BTW, I've had my experiences with lying Instruments. A faulty O2 gauge that always read lean ended up with me enriching the mixture so much that I washed the cylinder bores clean with fuel. I should have trusted the plugs which said that the engine was Pig rich... but no.. I trusted the O2 gauge too much and it ended up costing me an engine.
I think Keith had a problem with a low reading Pyrometer many years ago before he put in the Intercooler. Faulty probe wasn't it Keith?
I think Keith had a problem with a low reading Pyrometer many years ago before he put in the Intercooler. Faulty probe wasn't it Keith?
- bertvorgon
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Re: Fun with needles
Not to take away the thread..gauges can be an issue. I have had probes fail, after giving give me an erroneous reading. I finally installed the inter-cooler after I put in the temp probe to actually see what my temp was, going into the engine at the top of Knox. It was almost 400+F...Holy Crikes!
Sometimes as Richard said, it is good to go back to the old and time proven methods of tuning. It is hard to not look at your plugs and not have the real sense of how the mixture is burning.
His method of testing the plug/mixture is spot on. I still use it!
I use my gauges as a guide line.
Sometimes as Richard said, it is good to go back to the old and time proven methods of tuning. It is hard to not look at your plugs and not have the real sense of how the mixture is burning.
His method of testing the plug/mixture is spot on. I still use it!
I use my gauges as a guide line.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
- SteveEdmonton
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Re: Fun with needles
Richard and Keith, thank you for taking the time to explain what experience has taught you. This is why I invest the time to explain what I'm doing at this end, hoping for these kinds of responses. You guys are helping me so much!
About the "cruising" AFR readings in the 18-19 range: You're exactly right that it doesn't run well at that point. Lots of hesitation. That's why I "always" pull out the choke (except for part of yesterday's test-run, when I wanted to establish that that really was the reading), bringing the readings down to the 15-16 range. At that point it smoothens out considerably and feels much better. If I give it more choke, pulling the ratio down to 13-14, it doesn't really seem to run any better (ie smoother, according to my butt and ears) than it does at 15-16. But ratios any higher than that are distinctly and obviously unhealthy-- I know that both cognitively and experientally. I'm taking your point, no question.
My WBO2 has the world's crappiest set of instructions, and at one point I mentioned getting zero customer-support from the manufacturer. Wish I'd bought a different brand. I did though figure out-- through reading and re-reading their poor info sheet, through watching videos, and through trial nad error-- how to calibrate the damn thing in "fresh air." And I did so. Unless I did it wrong, I think it's calibrated right. And it's only got about 600 miles on it.
I had no idea that silicone could contaminate the sensor. Thanks for sharing this! Thinking back on the engine build, I don't recall using any RTV in any places that would affect the "breathing tract." But even if I'm forgetting something, I ran & drove the motor for about 100 miles before getting this new exhaust system built, which is when the WBO2 was installed.
Re. timing, static advance is at 12 degrees right now. My adjustable timing light suggests maximum mechanical advance (static + centrifugal) is about 28 degrees. This last batch of tests (yesterday) were run with the vacuum advance also hooked up, and as noted somewhere before I don't really know what it's set at. When I rev the engine in the driveway with it hooked up, it looks to me like the total advance is over 40 degrees.
I expressed my concern about that high number a while ago, but found some reassurance in somebody's comment that that was OK because in actual driving conditions the vacuum wouldn't kick in at the same time the centrifugal advance was at its maximum. At least that's what I remember... and it sort of made sense. But to be honest, I was "happier" without the vacuum hooked up, due to my fear of pinging / detonation. I have zero desire to wreck this sweet (not to mention expensive) new motor!
I think I'm going to try 3 things in the next little while, 2 of them building on these suggestions and 1 idea of my own.
1) Rig up a fresh-air feed to the carbs, maybe through a headlamp socket, and go for a run on this same "test section" of freeway with the hood installed. I don't want to cling to a flawed piece of data for too long, but to me this is the "smoking gun" that demands an answer, why the ratios are so stable in both of those broad conditions-- one set of stable numbers with the hood off, and another set of stable numbers with the hood on-- but at the same time so wildly divergent at highway speed / load between those two sets of conditions.
2) Run a new set of plugs and test the mixture using them, as you suggest. I pulled & checked the plugs on the weekend while doing the other 500-mile maintenance (oil change, tightening head-bolts, adjusting valves, checking compression) and they "looked fine" to me, but your invitation to post pics for expert analysis is welcome. Thank you.
3) If need be, maybe I'll lay out the $$ to have Ken Miles, the ex-racer MG mechanic I rely on, check my work and (hopefully) build on it. He has decades of experience, mostly on British stuff but also to some extent with Datsuns (mostly Z-cars).
Other ideas are welcome too. But on the other hand, there already seem to be a few good ideas on the table.
About the "cruising" AFR readings in the 18-19 range: You're exactly right that it doesn't run well at that point. Lots of hesitation. That's why I "always" pull out the choke (except for part of yesterday's test-run, when I wanted to establish that that really was the reading), bringing the readings down to the 15-16 range. At that point it smoothens out considerably and feels much better. If I give it more choke, pulling the ratio down to 13-14, it doesn't really seem to run any better (ie smoother, according to my butt and ears) than it does at 15-16. But ratios any higher than that are distinctly and obviously unhealthy-- I know that both cognitively and experientally. I'm taking your point, no question.
My WBO2 has the world's crappiest set of instructions, and at one point I mentioned getting zero customer-support from the manufacturer. Wish I'd bought a different brand. I did though figure out-- through reading and re-reading their poor info sheet, through watching videos, and through trial nad error-- how to calibrate the damn thing in "fresh air." And I did so. Unless I did it wrong, I think it's calibrated right. And it's only got about 600 miles on it.
I had no idea that silicone could contaminate the sensor. Thanks for sharing this! Thinking back on the engine build, I don't recall using any RTV in any places that would affect the "breathing tract." But even if I'm forgetting something, I ran & drove the motor for about 100 miles before getting this new exhaust system built, which is when the WBO2 was installed.
Re. timing, static advance is at 12 degrees right now. My adjustable timing light suggests maximum mechanical advance (static + centrifugal) is about 28 degrees. This last batch of tests (yesterday) were run with the vacuum advance also hooked up, and as noted somewhere before I don't really know what it's set at. When I rev the engine in the driveway with it hooked up, it looks to me like the total advance is over 40 degrees.
I expressed my concern about that high number a while ago, but found some reassurance in somebody's comment that that was OK because in actual driving conditions the vacuum wouldn't kick in at the same time the centrifugal advance was at its maximum. At least that's what I remember... and it sort of made sense. But to be honest, I was "happier" without the vacuum hooked up, due to my fear of pinging / detonation. I have zero desire to wreck this sweet (not to mention expensive) new motor!
I think I'm going to try 3 things in the next little while, 2 of them building on these suggestions and 1 idea of my own.
1) Rig up a fresh-air feed to the carbs, maybe through a headlamp socket, and go for a run on this same "test section" of freeway with the hood installed. I don't want to cling to a flawed piece of data for too long, but to me this is the "smoking gun" that demands an answer, why the ratios are so stable in both of those broad conditions-- one set of stable numbers with the hood off, and another set of stable numbers with the hood on-- but at the same time so wildly divergent at highway speed / load between those two sets of conditions.
2) Run a new set of plugs and test the mixture using them, as you suggest. I pulled & checked the plugs on the weekend while doing the other 500-mile maintenance (oil change, tightening head-bolts, adjusting valves, checking compression) and they "looked fine" to me, but your invitation to post pics for expert analysis is welcome. Thank you.
3) If need be, maybe I'll lay out the $$ to have Ken Miles, the ex-racer MG mechanic I rely on, check my work and (hopefully) build on it. He has decades of experience, mostly on British stuff but also to some extent with Datsuns (mostly Z-cars).
Other ideas are welcome too. But on the other hand, there already seem to be a few good ideas on the table.
'71 4-door
'74 MGB-GT
'04 Miata
'74 MGB-GT
'04 Miata
- SteveEdmonton
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Re: Fun with needles
This is a loose end I don't think I've responded to.bertvorgon wrote: How is the VOLUME of fuel going to those carbs?
In short, I don't think I'm running out of fuel when these lean AFR numbers appear. The reason? When I pull out the choke, the numbers drop. I'm thinking that means that the fuel is available in the float bowl, just not getting metered into the motor fast enough.
Last edited by SteveEdmonton on 01 Oct 2015 19:46, edited 1 time in total.
'71 4-door
'74 MGB-GT
'04 Miata
'74 MGB-GT
'04 Miata
- SteveEdmonton
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Re: Fun with needles
Another couple loose ends from Julian's posts to comment on:
Yeah, that's basically what I was thinking toward, too. I half-understood that same possibility... you've said it more clearly than I'd been able to.An alternative idea is...at cruise, your SU pistons never see enough vacuum to overcome the additional spring pressure, and so are always slightly lower than they want to be, so the accel pump effect is always taking place. SU pistons rise inversely to manifold vacuum.
Agreed. My test runs last night were intended, before I started them, to nail down which stations needed re-profiling. I'd been completely satisfied with the AFR under all conditions except freeway driving, but I wanted to clarify where to start thinning the needles appropriately to address that lean running under those conditions. As you say, this hood on / hood off difference that I stumbled onto, now has me second-guessing "the real problem" too. But apart from that, and maybe still in spite of that, YES I am fully ready to fine-tune these British #7 needles that I'm running with. Hood-off, they seem pretty much perfect--just a tiny bit of richening needed for highway conditions. And even with the hood on, it's still only those "highway settings" that seem to need work, just quite a bit more of it than with the hood off.perhaps this is just a fueling issue related to needles and it can be fixed by swapping needles or reprofiling the ones you have? Have I convinced you? I'm not sure I've convinced myself, mainly due to your hood on/hood off observations of AFR.
Anyway, if you're buying the above, maybe you look to set the needles wherever and after more AFR-to-needle-station observations you reprofile your needles to suit? I think you're going to need to go there at some point anyway, but I'm not sure it'll be the answer to everything you're seeing.
'71 4-door
'74 MGB-GT
'04 Miata
'74 MGB-GT
'04 Miata
Re: Fun with needles
Total advance (static + mechanical) should be in the low 30s for an L20B. Vac advance is not counted in that total. Vac advance is only initiated during times of high manifold vacuum, i.e. under some cruising conditions. This ignition system is designed to work this way. During your free-rev where you saw 40+ degrees of advance, there's zero load on the engine. Same as how you can't get a turbo to spool up by free-reving the engine in your garage, no load.
You can run tests hood on/hood off, fresh air tubes, etc., but IMO you're going to get confused by things that don't matter. You're going to drive you car with the hood on, so tune for that. If you're going to drive it with a fresh air tube, build it and then tune for that. As a weird outlier, the hood-off numbers are interesting, but I think they're getting you off track of what really matters.
Plug test - what is suggested above is known as a cut test, the idea being to get a snapshot look at the plug at a specific running condition. Plug condition over time (your look at your plugs after 500 miles) is also a good indicator of overall performance, but is very different from the cut test.
You can run tests hood on/hood off, fresh air tubes, etc., but IMO you're going to get confused by things that don't matter. You're going to drive you car with the hood on, so tune for that. If you're going to drive it with a fresh air tube, build it and then tune for that. As a weird outlier, the hood-off numbers are interesting, but I think they're getting you off track of what really matters.
Plug test - what is suggested above is known as a cut test, the idea being to get a snapshot look at the plug at a specific running condition. Plug condition over time (your look at your plugs after 500 miles) is also a good indicator of overall performance, but is very different from the cut test.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
- bertvorgon
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Re: Fun with needles
Regardless of float level, when you pull out the choke you are effectively decreasing the air going into the motor, which then richen's the mixture, just say'in.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
Re: Fun with needles
Steve, thinking about this this morning. When you lowered the needles .020, why did you not raise the fuel jet .020" instead?
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
- SteveEdmonton
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Re: Fun with needles
Good question. Because the jet is already all the way up.Steve, thinking about this this morning. When you lowered the needles .020, why did you not raise the fuel jet .020" instead?
'71 4-door
'74 MGB-GT
'04 Miata
'74 MGB-GT
'04 Miata
Re: Fun with needles
Interesting. Does not a fully-raised jet reach the bottom of the jet bridge? It's been a while since I worked with SUs, though I can't recall ever running the jets fully-raised. If not, how far from the bridge is the jet?
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
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Re: Fun with needles
You're on the right track. You just need to fine tune your fuel curve some more.
I think I would have used a set of 240Z needles as a starting point for this. Or better yet, SSS needles if you can find them Profile should be closer to what you than the British SU needles, in regards to idle richness. Edit: Or re-profile your British needles as you have mentioned. I've used a drill press, fine emery cloth and a set of Digital calipers. Work carefully and you can get the profiles spot on.
Do check the float level as well ( if you have not already done so ) as that will drastically affect fuel mixture. More so at mid-range and high RPM than idle.
Glad you clarified that the engine ran poorly at 18.5 and 19 to 1. That eliminates a lot of variables and correlates with your AFR readings. Makes more sense.
The vacuum advance is fine leave it connected. Mechanical curve seems fine as well. You just need to sort out your fuel curve.
I think I would have used a set of 240Z needles as a starting point for this. Or better yet, SSS needles if you can find them Profile should be closer to what you than the British SU needles, in regards to idle richness. Edit: Or re-profile your British needles as you have mentioned. I've used a drill press, fine emery cloth and a set of Digital calipers. Work carefully and you can get the profiles spot on.
Do check the float level as well ( if you have not already done so ) as that will drastically affect fuel mixture. More so at mid-range and high RPM than idle.
Glad you clarified that the engine ran poorly at 18.5 and 19 to 1. That eliminates a lot of variables and correlates with your AFR readings. Makes more sense.
The vacuum advance is fine leave it connected. Mechanical curve seems fine as well. You just need to sort out your fuel curve.
Last edited by Chickenman on 02 Oct 2015 10:58, edited 3 times in total.
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Re: Fun with needles
Actually, on an SU style carb, the Air flow is not changed. The " choke " lever is really a " Cold start enrichment " and lowers the Jet nozzle thus enriching the mixture. Just to be " technically correct"bertvorgon wrote:Regardless of float level, when you pull out the choke you are effectively decreasing the air going into the motor, which then richen's the mixture, just say'in.
Last edited by Chickenman on 02 Oct 2015 10:39, edited 1 time in total.
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Re: Fun with needles
As you have found, Air intake temperatures dramatically change Air Fuel Ratios on carburated cars. It's the under-hood air temperature that changes with the Hood off, and that changes air density which changes your fuel curve. Cold Air Intakes also dramatically affect carburated cars... as previously mentioned.
EFI with Barometric sensors or MAP sensors and IAT sensors made such a difference. They are able to Automatically compensate for differences in Air density due to atmospheric, altitude or temperature variances. That's why modern cars all can run Cold Air intakes with such accuracy.
Unfortunately, carbed cars have no way to compensate automatically for Air Intake Temperature or Air Density. During the 70's and early 80's car manufacturers ran carburated cars with air Intakes sourced to hot under hood intakes. Although the under hood Temps were Hot and gave up Power and Economy... but they were more stable for Emissions testing.
Performance guys all ran Hood scoops, Cold air rams etc.... but they were a SOB to set up for emissions testing due to varying temperatures.
One of the main reasons why Pro Stock Drag racing ( and Nascar ) have finally ditched carburators and gone to EFI was the cost involved of having to have extra carbs. Pro Stock racers had several dozen pre-jetted carbs ready to go at an instance for every slight atmospheric deviation. They often had hundreds of thousands of dollars in extra carburators in the Trailer and back in Race shops to cover all conditions. ( Warren Johnston estimated $150,000 in 2000 ) Digital fuel injection systems took care of all of that automatically with one set of hardware.
EFI with Barometric sensors or MAP sensors and IAT sensors made such a difference. They are able to Automatically compensate for differences in Air density due to atmospheric, altitude or temperature variances. That's why modern cars all can run Cold Air intakes with such accuracy.
Unfortunately, carbed cars have no way to compensate automatically for Air Intake Temperature or Air Density. During the 70's and early 80's car manufacturers ran carburated cars with air Intakes sourced to hot under hood intakes. Although the under hood Temps were Hot and gave up Power and Economy... but they were more stable for Emissions testing.
Performance guys all ran Hood scoops, Cold air rams etc.... but they were a SOB to set up for emissions testing due to varying temperatures.
One of the main reasons why Pro Stock Drag racing ( and Nascar ) have finally ditched carburators and gone to EFI was the cost involved of having to have extra carbs. Pro Stock racers had several dozen pre-jetted carbs ready to go at an instance for every slight atmospheric deviation. They often had hundreds of thousands of dollars in extra carburators in the Trailer and back in Race shops to cover all conditions. ( Warren Johnston estimated $150,000 in 2000 ) Digital fuel injection systems took care of all of that automatically with one set of hardware.
Last edited by Chickenman on 02 Oct 2015 11:14, edited 2 times in total.
- bertvorgon
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Re: Fun with needles
See... I said I know nothing about those carbs....I will go away now....
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer