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Engine Specific Info and Questions => IDI Engine => Topic started by: 8v-of-fury on May 18, 2010, 07:43:56 pm
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With EGT's that is...
I was having a dispute with another board member, and we came to some interesting points. I was saying that a little tweaking of my fuel screw and I can keep up with some Cummins' in the smoke belching contests, but at what cost to EGT's? His argument over this was that there is basically zero restriction after the engine (no turbo) to keep/hold any of that heat back, and that it should be very quickly expelled out the tail pipe. My rebuttal to this was that black smoke was a usual sign of VERY HIGH EGT's, because of all the extra fuel being injected and not burned. He cleverly came back with, if you were really injecting enough fuel to kill an N/a with EGT's it would be un-drivable and the likes.. HOWEVER! I came back with my water temps rising on a long grade, where i was obviously on it to keep up.. the gauge will rise 1/4-1/3 of the gauge.. there is a lot of heat being made somewhere eh?
What we really want to know, is what is actually happeneing inside an N/a motor when a lot of fuel is dumped in and that awesome black smoke appears? how much is it really affecting EGT's? We want theories, ideas, proof, anything really. Lets see what we all really know. :P
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Have you thought about purchasing a pyrometer? That would probably be the best way to find out.
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EGT is a function of fueling, and it will be undriveable once a piston seizes to the bore.
My data comes form the other side... running downhill I make 3-4 PSI, and my EGT runs about 200F
Boost does not EGT make
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I assume that if you retarded the timing enough, most of the combustion would take place outside the engine ad in the exhaust, giving lots of black smoke, and high EGT readings, but cool coolant ;D
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I know it is the fuel that makes the EGT's and usually you do not have to worry on an N/a because you are not usually pumping ungodly amounts of fuel in.. I don't plan to have this engine for too much longer, so I don't feel it deserves my time in installing a pyrometer. I am not talking of upping the fuel screw to crazy levels, more so on the gov mod. If I am conscious about what i'm dumping out the tail pipe.. I think stuff should be ok no?
What are peoples views on the fact that there is no restrictions?
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I assume that if you retarded the timing enough, most of the combustion would take place outside the engine ad in the exhaust, giving lots of black smoke, and high EGT readings, but cool coolant ;D
I very heavily retarded the timing on my 1.6TD in an effort to reduce oil smoke. The rings are badly worn out. I just added shims to the advance spring to delay the advance. The smoke levels went from burying the car behind me on gentle take off to what appears smoke free. I know that it is still smoking, it's just not visible to me. Boost seemed to pick up faster but my fuel mileage is about half of what it should be :( Unfotunately my EGT gauge is in a box so I can't comment on that.
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A NA can hit 1200+F but it will blow quite a bit of smoke. I'm reading off of two exhaust runners.
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With the EGT probe mounted at the confluence of the 4 runners (VW Fox gasser large bore single-outlet exhaust manifold), pump advance @ 1.02mm, and the fuel screw turned in just a bit (c. 1/4 turn?), my 1.6N/A can easily hit 1,300oF if the accelerator is floored for more than a few seconds. If any tires are low in pressure, it seems like the EGT will jump up almost instantly with your boot in it, especially in hard cornering(?). Personal preference is to try to stay below 900oF. Supposedly that is a safe 'crack-avoidance' maximum... YMMV!
Smoke... ah, sure, plenty of it out through the 2.25" exhaust system, when @ full pedal. But for economy's sake the idea is not to keep the pedal to the floor that long... or that often; that can make the difference between 36mpg vs. 45mpg, 'around town' fuel consumption. Steady state flat highway cruise mode rarely shows EGT over 450oF, but the engine's 3,000rpm torque peak occurs @ 83mph in 5th, or 64mph in 4th gear. Steady state cruise @ 105mph (3,800rpm) showed 750-850oF, with no perceptible smoke (or red lights/siren, thankfully).
J.R.
SoCal
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the engine's 3,000rpm torque peak occurs @ 83mph in 5th, or 64mph in 4th gear. Steady state cruise @ 105mph (3,800rpm) showed 750-850oF, with no perceptible smoke (or red lights/siren, thankfully).
J.R.
SoCal
What transmission is that???? I have a FN code, 3.89 final and .71 5th and 3000rpm = 70mph.
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105mph with a 1.6NA? Cool!
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105mph with a 1.6NA? Cool!
off a cliff...........
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the engine's 3,000rpm torque peak occurs @ 83mph in 5th, or 64mph in 4th gear. Steady state cruise @ 105mph (3,800rpm) showed 750-850oF, with no perceptible smoke (or red lights/siren, thankfully).
J.R.
SoCal
What transmission is that???? I have a FN code, 3.89 final and .71 5th and 3000rpm = 70mph.
Transaxle is the VW Quantum/Audi 4000 model 2M 5-speed, swapped into a 1980 Dasher, with 195/60-14 tires. 1st thru 5th gears respectively, are: 3.455, 1.70, 1.065, 0.778, 0.600, and R&P is a 4.111. Given the huge split between 1st & 2nd, its obviously not the best for a small diesel engine, or probably even the 1.7L gasser with which it came stock. The factory Quantum 1.6TDs got the 3M and 9Q transaxles with the preferable gear spread of 3.455/1.944/1.286/0.909/0.730, and same 4.111 final ratio.
wolf_walker commented: "105mph with a 1.6NA?"
Sure, but it's a while getting there, and that's on the flats, not pulling uphill against a big headwind. The Dasher is considerably heavier than the Rabbit/Golf Mk 1, but once rolling, may make up a bit due to better aerodynamics(?).
J.R.
SoCal
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195/60-14 tires. 1st thru 5th gears respectively, are: 3.455, 1.70, 1.065, 0.778, 0.600, and R&P is a 4.111.
That is a respective 3750 rpm. With the Gov Mod, fully attainable.
It appears my friend was incorrect ;)
Now lets say for arguments sake I found a way to do the Gov Mod without taking the pumps top off... Yet I kept the fuel screw at or below stock settings to keep the smoke as a gray wisp behind the car, or not even there at all. I have researched and tested a method, that effectively does the WOT part of what the Gov Mod does.. with nothing more then a wrench and screwdriver.
The full throttle stop is what i messed around with, and after talking to a local yocal around here that deals with these engines/pumps as a hobby. We came to the conclusion that if you were to back to the throttle stop out all the way and then manually move the throttle arm through its entire motion to where it doesn't want to turn anymore, and then bringing the stop screw to meet it in this position.. your effectively "Shimming" the governor assembly solid. Instead of taking it out and adding springs, and making the gov mod active %100 of the time and at all peddle positions, we now only have this full fueling when at WOT.
I tested this theory on my bone stock 1981 1.6 N/A, stock intake, stock 1.5" exhaust, and stock pump. I originally had the fuel screw turned in about 1/2 turn just so i could get the thick black smoke on those hard WOT pulls, it bumped my idle to around 1050-1100 I'd say. So i backed it down to where the idle sounded closer to stock or lower, probably 900. Did the adjustment to the throttle stop and went out for a highway test.
The 400m on ramp alone showed 112-115mk/h for an RPM of 5100-5200 in 3rd with my FF trans. ;) It kept pulling a little bit more but she was screaming, so I grabbed 4th and quickly (Not usually heard in context with a 1.6 N/a) climbed to and passed 130km/h. Last night I had absolutely no problems keeping up with my Gf in her 90 with the 1.8 whilst cruising the back roads.
I suggest anyone with a 1.6 N/A and bone stock pump go try this out, because I can vouch it is fueling... I wouldn't have pulled to 5200 in 3rd if it weren't ;)
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OK, if I'm reading your procedure correctly, altering the WOT stop screw is doing the same as the governer mod? The only difference would be you'd be getting the additional advance when at WOT?
No tweaking the fuel screw?
-Todd
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OK, if I'm reading your procedure correctly, altering the WOT stop screw is doing the same as the governer mod?
Essentially yes. By allowing your foot to pull the entire spring assembly further than it was intended too, you are effectively pulling the governor solid and forcing to it to fuel past its stock point. However let the pedal off 3/4 - 1" and you have the full functionality of the governor back.
The only difference would be you'd be getting the additional advance when at WOT?
Not entirely sure on this one Todd, I would assume so? What makes you think to ask this? Not that I'm saying your wrong, I would just like to know as well.
No tweaking the fuel screw?
I had my fuel screw tweaked up a bit to gain a few ponies, but mainly to Billow like a chimney when I really stood on it :P. Right now I believe judging by how low it sounds while its idling, I'd say I have my fuel screw backed out further then stock.
My stock and engine are bone stock and this has completely transformed it, I have visual soot proof that it is fueling more. Pre-fuel screw tweaking, WOT would only produce a slight wisp of soot out the back. Now with what I think is a lower then stock fuel screw setting, it will still be pumping out some black goodness. Even at 5000rpm ;) Yup third gear doing 110 km/h (70mph) screaming along at 5000 rpms :) and it pulled up there with ease. Its not like I was going down hill with a strong pushing wind, it will gain that speed on flat to moderate incline.
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OK, if I'm reading your procedure correctly, altering the WOT stop screw is doing the same as the governer mod? The only difference would be you'd be getting the additional advance when at WOT?
No tweaking the fuel screw?
-Todd
No it really wouldn't be the same. The spring would push back against the gov and limit fuel.
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But Lucas you are pulling the springs completely tight by pulling the whole governor assembly at least an inch passed its intended motion. Explain to me how I can quickly spin up to 5000 + ? if it were limiting fuel?
It's probably not giving it %100 of fueling, but its a hell of a lot better then %20 eh?
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nah my post was about the wide open throttle screw. I don't think it would be the same as the gov. mod. It might be, but I might not be thinking correctly about what is going on.
I am a full fleged member of the gov. mod crew ;) and completely agreee with you on how awesome it is. I had 2.5" exhaust, 3" pvc custom intake, and the gov. mod and it would pull like crazy. I had to watch myself on the freeway. I used to struggle to keep up with the 70MPH traffic. After the gov mod I did my usual floor it on the freeway and looked down...I was doing 84 MPH and still had more.
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I could most certainly hold 75-80 no problem on the highway before doing this half-mod as we will call it.. however this does not really change anything unless your foot is on the floor. IT for sure did something, not a substitute for the gov mod, but maybe a slight alternative for those not willing to open their pumps quite yet.
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"How high can an N/A get?"
I dunno, how tall is the nearest mountain? :D
Because nobody's made -that- crack yet in this thread...
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195/60-14 tires. 1st thru 5th gears respectively, are: 3.455, 1.70, 1.065, 0.778, 0.600, and R&P is a 4.111.
That is a respective 3750 rpm. With the Gov Mod, fully attainable.
It appears my friend was incorrect ;)
Now lets say for arguments sake I found a way to do the Gov Mod without taking the pumps top off... Yet I kept the fuel screw at or below stock settings to keep the smoke as a gray wisp behind the car, or not even there at all. I have researched and tested a method, that effectively does the WOT part of what the Gov Mod does.. with nothing more then a wrench and screwdriver.
The full throttle stop is what i messed around with, and after talking to a local yocal around here that deals with these engines/pumps as a hobby. We came to the conclusion that if you were to back to the throttle stop out all the way and then manually move the throttle arm through its entire motion to where it doesn't want to turn anymore, and then bringing the stop screw to meet it in this position.. your effectively "Shimming" the governor assembly solid. Instead of taking it out and adding springs, and making the gov mod active %100 of the time and at all peddle positions, we now only have this full fueling when at WOT.
I tested this theory on my bone stock 1981 1.6 N/A, stock intake, stock 1.5" exhaust, and stock pump. I originally had the fuel screw turned in about 1/2 turn just so i could get the thick black smoke on those hard WOT pulls, it bumped my idle to around 1050-1100 I'd say. So i backed it down to where the idle sounded closer to stock or lower, probably 900. Did the adjustment to the throttle stop and went out for a highway test.
The 400m on ramp alone showed 112-115mk/h for an RPM of 5100-5200 in 3rd with my FF trans. ;) It kept pulling a little bit more but she was screaming, so I grabbed 4th and quickly (Not usually heard in context with a 1.6 N/a) climbed to and passed 130km/h. Last night I had absolutely no problems keeping up with my Gf in her 90 with the 1.8 whilst cruising the back roads.
I suggest anyone with a 1.6 N/A and bone stock pump go try this out, because I can vouch it is fueling... I wouldn't have pulled to 5200 in 3rd if it weren't ;)
i messed with the WOT stop. tried all external adjustments on the pump. nothing made as big of a difference as doing the gov mod. theres no way anything on the outside of the pump can do what my 2 stainless nuts in the pump can do to throttle. i took my full throttle stop out, and advanced my throttle arm a spline. the gov mod is the winner in my books. how hard is it to take off the throttle arm and 4 screws? that too hard? i personally dont mind opening up my pump once in a while, just to tell how its doing.
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I'm not saying its a substitute, but it most certainly is doing the exact same thing for the WOT portion of it..
It is not an external pump mod, It is pulling the entire governor assembly an inch past its intended motion ever was. That makes it internal, by changing how tight you are pulling the governor together. I am not lying, my engine will fuel and pull all the way to 5500 with stock intake and exhaust. I'm sure it would pull way more if I had these two modded. Fer Sure.
I'm not bashing the gov mod, it does the full fueling at all throttle positions. There is a lot that can go wrong to a none experienced person opening one of these pumps. Smallest fleck of rust could eff up your day severely.. why chance it?