BOV is opening under boost
#151
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Re: BOV is opening under boost
let us know how long it lasts.
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
#152
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Re: BOV is opening under boost
let us know how long it lasts.
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
The new valve (blowoff, bypass, whatever) is working quite well. It's open under most part throttle and idle, closes when I 'get on it'. IAT temps are good.
So the only problem I'm having now is i'm getting some breakup or spark blowout. I have not had time to mess with it, but maybe soon I'll tinker some more.
Basically what's happening is the engine starts breakup up a little bit. It's not detonation, it's almost like it's losing some spark.
I know it's not the trigger because I'm not losing SYNC. I'm using an EDIS-8 ignition module, so my trigger is wired to the module. The module reports RPM to the ECU (PIP signal) and the Megasquirt tells the ignition module what advance to use (SAW signal). This communication is good.
What I'm not sure about is if the coils are having problems firing the plugs in the upper RPM's. I'm using stock Ford EDIS coils.
The module is pretty cool because even if for some reason the SAW signal from the Megasquirt was pooched, the EDIS module will keep the spark advance at the last commanded number for a period of time. (Although if the PIP signal from the module were to go away, I'd get 'sync loss' and the injectors wouldn't fire)
So.. maybe plug gap, maybe coil..
At record 181 we are at 4490 RPM
At record 182 we are at 4287 RPM
At record 185 we are at 4578 RPM
At record 187 we go back down to 4301 RPM
At record 201 we go up to 4912 RPM
At record 202 we go back down to 4690 RPM
Now, when I first get into boost my AFR nose dives - at record 162 @ 3662 RPM I'm at 9.5:1 AFR at 112.7 kpa. It leans out slowly until about record 175 where we are at 11:1 AFR and 4467 RPM @ 117.7 kpa.
Now the 'breakup' from what I can tell starts about record 178 where we are at 11.3:1 AFR and 4526 RPM @ 118.8 kpa Up to this point the RPM's are increasing steadily, but then:
At record 181 we are at 4490 RPM (11.1 AFR @ 118.9 kpa)
At record 182 we are at 4287 RPM (11.3 AFR @ 117.2 kpa)
At record 185 we are at 4578 RPM (11.1 AFR @ 119.0 kpa)
At record 187 we go back down to 4301 RPM (11.3 AFR @ 116.1 kpa)
At record 201 we go up to 4912 RPM (12.2 AFR @ 120.1 kpa)
At record 202 we go back down to 4690 RPM (12.1 AFR @ 122.5 kpa)
Then I let off the throttle.
I don't know what this data is really telling us. The duty cycle for most of this is in the high 80's, so we're delivering a substantial amount of fuel. At our highest point (record 206) right before I let off the throttle we are at 91.8 % duty cycle.
91.8% of 8 60lb injectors is 440.64 lbs/hr of fuel. Tell me I'm crazy but, at a BSFC of .55 that's like 800hp worth of fuel.
-- Joe
#153
Re: BOV is opening under boost
I am wondering if its much richer than you think at that duty cycle and drowning out the spark thus allowing fresh o2 into exhaust to fool your wideband reading. Happened to me but at high boost. I increased spark energy thru dwell and immediately went pig rich but cleaned up rpm trend. Then i could lean out and saw big gains
idk much about ford coils but it shouldnt take much effort to light off a few psi boost at 4500 rpm. Plug gap of .030 should handle that no issue if a true 11.3 afr. But i still would go more like .025-.027” or so for higher boost
i would def lean it out more and see if it cleans up. You arent making 800 hp at 2-3 psi at 4500 rpm. Alot of torque tho but not power yet. So your dc tells me it might be too rich and the wideband is reading false
idk much about ford coils but it shouldnt take much effort to light off a few psi boost at 4500 rpm. Plug gap of .030 should handle that no issue if a true 11.3 afr. But i still would go more like .025-.027” or so for higher boost
i would def lean it out more and see if it cleans up. You arent making 800 hp at 2-3 psi at 4500 rpm. Alot of torque tho but not power yet. So your dc tells me it might be too rich and the wideband is reading false
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Re: BOV is opening under boost
9.5:1 AFR at 1.8PSI & 3600RPM might be a little bit rich. I agree with Orr, definitely lean that bad larry out.
#155
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Re: BOV is opening under boost
happened to me but at high boost. I increased spark energy thru dwell and immediately went pig rich but cleaned up rpm trend. Then i could lean out and saw big gains
idk much about ford coils but it shouldnt take much effort to light off a few psi boost at 4500 rpm. Plug gap of .030 should handle that no issue if a true 11.3 afr. But i still would go more like .025-.027” or so for higher boost
i would def lean it out more and see if it cleans up. You arent making 800 hp at 2-3 psi at 4500 rpm. Alot of torque tho but not power yet. So your dc tells me it might be too rich and the wideband is reading false
-- Joe
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Re: BOV is opening under boost
Hows your VE table scaled ?
I have 25, 35, 40, 45, 50, 55, 65, 75, 85, 95, 100, 118, 136, 154, 172, 190
-- Joe
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Re: BOV is opening under boost
-- Joe
#159
Re: BOV is opening under boost
Until you find fuel ratio you could take it down a few degs if you wanna be real safe.
Code $59 had timing up to 4800 rpm and scales of 99, 115, 131, 146, 162, 178, 194. Fwiw my afr 195 turbo deal was in the 34 deg range at 99, 33 at 115, 30 at 131, 27 at 146, 22 at 162, 18.6 at 178.
But code $59 3 bar ve table is scaled 101, 110, 120, 130, 140, 150, 160, 169, 179, 189
Code $59 had timing up to 4800 rpm and scales of 99, 115, 131, 146, 162, 178, 194. Fwiw my afr 195 turbo deal was in the 34 deg range at 99, 33 at 115, 30 at 131, 27 at 146, 22 at 162, 18.6 at 178.
But code $59 3 bar ve table is scaled 101, 110, 120, 130, 140, 150, 160, 169, 179, 189
#160
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Re: BOV is opening under boost
With iat climbing like that at such low boost, If this was a turbo car I'd say boost leak 100%
You shouldn't see much if any IAT rise at all until around 10-12psi of boost or the intercooler is a piece of crap (for most turbo cars)
-still suggesting pressure test and intake air pathway inspection (for obstructions or whatever, oil etc)
-followed by look up the dwell times for those coils, could simply be a setting (not enough or too much dwell) if there was no pre-set this is common
-and finally the injectors on-time is troubling. It suggests either
A: dropping fuel pressure (fuel feed inadequacy/obstruction or regulator malfunction or similar)
or B: injector response-time setting (response curve) but this is unlikely for WOT fueling to be much affected unless it was WAY off
or C: computer dropping injector current for some reason (Thinks they are "low" impedance when they are "high" or when using low impedance and poor computer source power/fusing conditions/grounds)
For such a high IAT I would be pulling out timing like no tomorrow. 3psi it won't hurt to have 15* in fact for 3psi in my 5.3L from 2002 I run about 13* and it really moves with ambient IAT which doesn't budge. If I pull it out to 10* it gets notably slower so I know I am in the right ballpark. I would suggest a similar tactic once you verify no boost leaks, pull out timing till it slows way the **** down and add some back until you can't tell the difference between 1 degree. Save the timing push for the dyno or if you ever get an EGT.
You shouldn't see much if any IAT rise at all until around 10-12psi of boost or the intercooler is a piece of crap (for most turbo cars)
-still suggesting pressure test and intake air pathway inspection (for obstructions or whatever, oil etc)
-followed by look up the dwell times for those coils, could simply be a setting (not enough or too much dwell) if there was no pre-set this is common
-and finally the injectors on-time is troubling. It suggests either
A: dropping fuel pressure (fuel feed inadequacy/obstruction or regulator malfunction or similar)
or B: injector response-time setting (response curve) but this is unlikely for WOT fueling to be much affected unless it was WAY off
or C: computer dropping injector current for some reason (Thinks they are "low" impedance when they are "high" or when using low impedance and poor computer source power/fusing conditions/grounds)
For such a high IAT I would be pulling out timing like no tomorrow. 3psi it won't hurt to have 15* in fact for 3psi in my 5.3L from 2002 I run about 13* and it really moves with ambient IAT which doesn't budge. If I pull it out to 10* it gets notably slower so I know I am in the right ballpark. I would suggest a similar tactic once you verify no boost leaks, pull out timing till it slows way the **** down and add some back until you can't tell the difference between 1 degree. Save the timing push for the dyno or if you ever get an EGT.
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Re: BOV is opening under boost
Until you find fuel ratio you could take it down a few degs if you wanna be real safe.
Code $59 had timing up to 4800 rpm and scales of 99, 115, 131, 146, 162, 178, 194. Fwiw my afr 195 turbo deal was in the 34 deg range at 99, 33 at 115, 30 at 131, 27 at 146, 22 at 162, 18.6 at 178.
But code $59 3 bar ve table is scaled 101, 110, 120, 130, 140, 150, 160, 169, 179, 189
Code $59 had timing up to 4800 rpm and scales of 99, 115, 131, 146, 162, 178, 194. Fwiw my afr 195 turbo deal was in the 34 deg range at 99, 33 at 115, 30 at 131, 27 at 146, 22 at 162, 18.6 at 178.
But code $59 3 bar ve table is scaled 101, 110, 120, 130, 140, 150, 160, 169, 179, 189
New problem, it makes boost until about 5100 RPM, then I heard some nasty *** squealing and the log shows boost goes to 0 as it continues to rev until 5800 when I let off.
I'm assuming at this point the belt is slipping, but it's tight AF and 10 rib..
-- Joe
#165
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Re: BOV is opening under boost
thats the ugly side of superchargers. "belt" this "bracket flexing" that until you have a 50mm cog setup and a bunch of time in a stout bracket setup. we put a cog belt on a buddies ysi car and we are still talking belts because its only a 30mm belt and holding on for dear life.
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Re: BOV is opening under boost
You have EGO control on over 100KPA? Whats your target AFR?
I wonder if you got a blown out gasket somewhere or a loose clamp. Time for a smoke test
Were you having boost issues last year?
Last edited by 86CamaroDan; 05-31-2019 at 04:13 PM.
#167
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Re: BOV is opening under boost
I dont honestly remember. I cant seem to find a picture of it at the moment. I know it starts at 15kpa, goes to 100/ 127.5(4PSI)/155(8PSI)/182.7(12PSI) but mines never gone past 155kpa
You have EGO control on over 100KPA? Whats your target AFR?
I wonder if you got a blown out gasket somewhere or a loose clamp. Time for a smoke test
Were you having boost issues last year?
You have EGO control on over 100KPA? Whats your target AFR?
I wonder if you got a blown out gasket somewhere or a loose clamp. Time for a smoke test
Were you having boost issues last year?
I checked the clamps. All tight. I'll probably do a pressure test although the screeching I heard makes me think maybe a belt, although I guess it could also be the tires breaking loose. Now that I think about it, the car kicked out sideways. In theory if the tires broke loose it would also unload the engine and there wouldn't be any boost.
It's difficult trying to tune WOT on highway on ramps while trying to keep it reasonably around the speed limit, which essentially means holding either first or second gear WOT.
Hopefully in a few weeks I'll be able to take it to the track for some more specific tuning. I need to install a winch in my enclose trailer though in the event of a breakdown.
Last year the tires broke loose every time I got into it, so I bought new tires but then I just got busy with other things and I only really drove it to car shows. This year I'm hoping to get some track time in but, I have a Harley, a few cars, a side by side, two jetskis, two jet boats, a larger bowrider, and a few properties that always need maintenance. So who knows what I'l have for time.
-- Joe
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Re: BOV is opening under boost
thats the ugly side of superchargers. "belt" this "bracket flexing" that until you have a 50mm cog setup and a bunch of time in a stout bracket setup. we put a cog belt on a buddies ysi car and we are still talking belts because its only a 30mm belt and holding on for dear life.
When I used to run S-Trims on stock vortech brackets they would flex and it would throw 6 rib belts occasionally.
We shall see. If it is belt slip there is things we can do to mitigate that. I'm not sure why COG drives are so expensive. I can understand the belt costing a premium, but $480 for a single pulley? I'll need to research that more.
30mm is kinda narrow, whats that like an inch and an eighth? A 50mm is almost a half inch wider than my 10 rib, and of course being a cog/gilmer drive you'd think it couldn't slip or skip.
I'm running A gates micro V K100579 right now. I don't know if maybe there is a better compound to be had..
-- Joe
#169
Re: BOV is opening under boost
In theory if the tires broke loose it would also unload the engine and there wouldn't be any boost.
you’ll just have to get it in high gear, get some speed built up to keep them tires planted lol
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Re: BOV is opening under boost
I've never bothered to really think about why or care. But I know at the same RPM I'll make more boost in higher gears than lower gears on previous supercharged setups because the engine is loaded more.
I agree, airflow should be the same though as impeller speed isn't changing.
Some quick research, this is the exact belt Vortech uses and recommends so I don't think it's a compound issue. I feel like it's tight AF and I don't really want to overtighten it.
I kinda feel like if I had some dyno time I could visually see what is going on.
-- Joe
#171
Re: BOV is opening under boost
Yeah just saying there is some load while spinning tire depending how fast you are going lol. I wouldnt have expected it to drop all the way out but then again you were only seeing 3 psi to begin with so maybe that makes sense lol. Pulley up
#172
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Re: BOV is opening under boost
let us know how long it lasts.
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
Also I'm not sure I would brag about that
many do not yet realize that 'air' is a fluid and can be used as an abrasive destructive molecular set of objects if directed properly with sufficient force
I wonder what sort of forces the tip of a compressor wheel experiences..... during boost.... during surge
Last edited by tom86iroc; 06-01-2019 at 08:46 AM.
#173
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Re: BOV is opening under boost
If you held it at 6500rpm in neutral with no bypass the air would surge back out the compressor instead and make an awful noise I assume
it's held together for 20 years so i'd say it works just fine lol oh and stock chip no tune lol
Also the tuning of an engine has nothing to do with the rate of wear and tear of a supercharger head unit.
All superchargers wear out over time and I suspect that any supercharger from any manufacturer would have a hard time making it to 200,000 miles (20 years of actual driving) without issues.
#174
Re: BOV is opening under boost
Okay, so it's been about a week in which I kept myself from this thread, has anything worked? Any resolution to the original complaint? In the few short responses here, I am reading how "most people" don't know that air is a "fluid", so right there this is an assumption on this person's part that is absolutely hilarious, and completely irrelevant. Yes, it is a fluid. And? The pathway of a given resistance has not been restricted entirely, so the point of air being a fluid is completely moot other than to inflate one's own ego by assuming everyone here didn't already know that. Swing and a miss. What's next? Ahh, a "tune" will not have an effect on the overall condition of a supercharger's head unit. Hmm, perhaps a "self contained" head unit would be the more appropriate in that case in which it is not being subjected to unburned fuel, and overheated engine oil, which a bad tune will produce, in turn creating less overall oil viscosity, and the inevitable demise of the head unit. Especially in this case because it is not self contained. Meh, members still trying to beat their chest along with the dead horse right underneath them. Will check back again soon, hopefully we'll see one wot pull after all these years and knowledge of tuning this particular engine...
- Rob
- Rob
#175
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Re: BOV is opening under boost
because vacuum in the intake manifold pulls open the bypass which lets the boost out
If you held it at 6500rpm in neutral with no bypass the air would surge back out the compressor instead and make an awful noise I assume
I assembled a motor once and it sat in the corner of a shop for 20 years only ran once. So telling people that **** lasts 20 years is meaningless.
Also the tuning of an engine has nothing to do with the rate of wear and tear of a supercharger head unit.
All superchargers wear out over time and I suspect that any supercharger from any manufacturer would have a hard time making it to 200,000 miles (20 years of actual driving) without issues.
If you held it at 6500rpm in neutral with no bypass the air would surge back out the compressor instead and make an awful noise I assume
I assembled a motor once and it sat in the corner of a shop for 20 years only ran once. So telling people that **** lasts 20 years is meaningless.
Also the tuning of an engine has nothing to do with the rate of wear and tear of a supercharger head unit.
All superchargers wear out over time and I suspect that any supercharger from any manufacturer would have a hard time making it to 200,000 miles (20 years of actual driving) without issues.
#176
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Re: BOV is opening under boost
hmm maybe you don't realize why I am here
I am here because its fun to point out every possible situation which has been unmentioned or unsaid
if it became appropriate i would point out that six times seven is.... wait, I have to check my calculator
I am here because its fun to point out every possible situation which has been unmentioned or unsaid
if it became appropriate i would point out that six times seven is.... wait, I have to check my calculator
#177
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Re: BOV is opening under boost
you>re funny you ask how long it'll last i tell you and dismiss it lmao i 've been to the track and raced this car did 13.1 @104 iirc should"ve done 12'9 ish but have never weighed the car. So don't tell me my motor sat in a corner for 20 years lol and of course a superecharger doesnt last 20 years that's what a rebuilt kit is for
when you realize that doesn't exist (I hope I am wrong though) and that you're apparently comparing two completely different kinds of superchargers,
and that the idea of surge is only applicable to compressor-wheel (turbocharger compressor) style of supercharger,
it would negate (make irrelevant) the entire argument about how long the different kind of supercharger is lasing (if the number of years is what matters, as this is the data you supplied, and not the usage) unless you are actually saying there are compressor wheel style supercharger rebuild kits (too lazy to search lmk)
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Re: BOV is opening under boost
I tightened the belt some more, I used a beam style torque wrench and put 110 lbs on the tensioner. Not sure the ratio so I don't know what that does in terms of belt tension.
Anyhow, so we're getting 6psi now at around 6200 rpm, and it pulls hard. No breakup after trimming out the fuel table.
Although now I'm hitting 118% injector duty cycle and my wide band is showing it run lean after about 3.2 psi.
I'm at like 11.5:1 until about 3.2, the it goes 12:1,
At 4.5 psi I hit 101% duty cycle and my AFR is 14.5:1
And by the time I hit 6 psi I'm at like 113% duty cycle at 16 AFR!
I need to log my fuel pressure and see if I'm getting pressure drop. I'm fairly confident that the AFR is correct this time because I seem to have got a lean pop right before I let off.
Injector PW 22 msec @ 6090 RPM, with an injection strategy of 2 squirts per CYCLE, every other bank.
This makes for a happy idle but I wonder if maybe dead time is killing my WOT fueling.
(those used to GM ECM's might be confused about the pulse width vs duty cycle. At 6,000 RPM it takes 20ms to complete a cycle of two revolutions. On a typical GM ECM it would fire BOTH injectors twice per cycle, (once per revolution). So your max time open per fire is 10ms. On the MS when firing twice per cycle but bank to bank you have a total possible open time of 20 ms per bank because you are only firing each bank once per cycle.)
In any event, a duty cycle of 113% yet lean AFR is beyond suspect. The car feels fast, but it's not making 873 crank hp...
-- Joe
Anyhow, so we're getting 6psi now at around 6200 rpm, and it pulls hard. No breakup after trimming out the fuel table.
Although now I'm hitting 118% injector duty cycle and my wide band is showing it run lean after about 3.2 psi.
I'm at like 11.5:1 until about 3.2, the it goes 12:1,
At 4.5 psi I hit 101% duty cycle and my AFR is 14.5:1
And by the time I hit 6 psi I'm at like 113% duty cycle at 16 AFR!
I need to log my fuel pressure and see if I'm getting pressure drop. I'm fairly confident that the AFR is correct this time because I seem to have got a lean pop right before I let off.
Injector PW 22 msec @ 6090 RPM, with an injection strategy of 2 squirts per CYCLE, every other bank.
This makes for a happy idle but I wonder if maybe dead time is killing my WOT fueling.
(those used to GM ECM's might be confused about the pulse width vs duty cycle. At 6,000 RPM it takes 20ms to complete a cycle of two revolutions. On a typical GM ECM it would fire BOTH injectors twice per cycle, (once per revolution). So your max time open per fire is 10ms. On the MS when firing twice per cycle but bank to bank you have a total possible open time of 20 ms per bank because you are only firing each bank once per cycle.)
In any event, a duty cycle of 113% yet lean AFR is beyond suspect. The car feels fast, but it's not making 873 crank hp...
-- Joe
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Re: BOV is opening under boost
I'm gonna look at pressure drop and go from there. I need a 5volt fuel pressure sensor. Might as well add a second map sensor and iat before the IC while I'm at it.
-- Joe
#183
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Re: BOV is opening under boost
<wheres the like button>
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Re: BOV is opening under boost
They are Deka 60# injectors.
I'm running 3/8 (-6) fuel line. I know some people step up to -8 or even -10 but the pump pickup, outlet are all 3/8", and the fuel rails are set up for 3/8" so without doing a custom pickup or sump and upgrading the fuel lines I don't think going to a bigger line would do anything.
-- Joe
I'm running 3/8 (-6) fuel line. I know some people step up to -8 or even -10 but the pump pickup, outlet are all 3/8", and the fuel rails are set up for 3/8" so without doing a custom pickup or sump and upgrading the fuel lines I don't think going to a bigger line would do anything.
-- Joe
#187
Re: BOV is opening under boost
Yeah the longer the line the more loss stacks up lol. But a single -6 should feed that setup. -8 would certainly eliminate any concern tho and make the short sections of 3/8 the restrictions. I found the -6/ 3/8” type outlet of the factory 4th gen gas tank, although only few inches in length, was limited to 1100 whp at 65 psi
#188
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, LT1
Transmission: TKX, 4L60E
Axle/Gears: 3.42, 3.23
Re: BOV is opening under boost
Yeah the longer the line the more loss stacks up lol. But a single -6 should feed that setup. -8 would certainly eliminate any concern tho and make the short sections of 3/8 the restrictions. I found the -6/ 3/8” type outlet of the factory 4th gen gas tank, although only few inches in length, was limited to 1100 whp at 65 psi
I come off the factory sending unit (aftermarket spectre) and go from saginaw to -6. I rain new steel lines which I flared to -6 AN angle. Steel lines turn into PTFE braided in the engine bay. It should be pretty good, although miniram fuel rail's are suspect with no front crossover. I still think it should be fine though, there are guys running stupid ET's with minirams.
I ordered some pressure sensors. When they come in I'll wire them up to a spare ADC so I can log both fuel pressure and pre-intercooler pressure.
I know one thing, yesterday I was messing with the car and the supercharger is HOT. Like you can't even touch it hot, yet the elbow to the throttle body is cool, almost cold. So the FMIC is most definitely doing it's job. I think the supercharger is sucking in a lot of hot
air. The proximity to the headers of both the head unit and the air cleaner is poor. Then, figure the hot oil lubrication.
I think the C4 LT1 setups are better with the reverse rotation blower and the air intake facing forward. The only down side is the 6 rib belt it shares with factory accessories.
-- Joe
#189
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Re: BOV is opening under boost
supercharger is probably hot from the engine oil passing through it, mostly. the blower car i mess with is the same way- i thought i burned my hand on it a few times.
what size upper pulley are you running? i would be interested to see if a larger pulley would show an increase in boost....
what size upper pulley are you running? i would be interested to see if a larger pulley would show an increase in boost....
#190
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Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, LT1
Transmission: TKX, 4L60E
Axle/Gears: 3.42, 3.23
Re: BOV is opening under boost
supercharger is probably hot from the engine oil passing through it, mostly. the blower car i mess with is the same way- i thought i burned my hand on it a few times.
what size upper pulley are you running? i would be interested to see if a larger pulley would show an increase in boost....
what size upper pulley are you running? i would be interested to see if a larger pulley would show an increase in boost....
I'm running a 7.8" crank pulley and a 3.33" supercharger pulley. Tightening the belt did appear to double the boost and I couldn't hear it squealing on the last run, but it went way lean so I need to figure out my fuel issue.
But in any event, that pulley combination puts me at 50,000 RPM at 6200 crank RPM. The max efficient impeller speed is 52,000 on this blower with an absolute max of 55,000, so the smallest blower pulley I could really go to is a 3.12 which would put me just past max efficient RPM at shift but keep me under the max RPM threshold.
That little note about COG being recommended for all heavy duty superchargers kinda makes me wanna just pony up and go cog. Seems like it would eliminate a lot of BS. But, at the same time, the mustang guys all run 10 rib with no issues.
-- Joe
#191
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Car: 86' IROC
Engine: Supercharged 350
Transmission: T56
Axle/Gears: 3.45
Re: BOV is opening under boost
Intresting. Im running 75-80 lbs of tension on mine. I'm switching to a gatorback belt soon, i think my 3.25" is too small and the belt is bulging under the amount of wrap it has.
I don't lose all the boost when i get tire spin, but there's definitely a drop in the boost level. You can see it drop quite a bit.
I don't lose all the boost when i get tire spin, but there's definitely a drop in the boost level. You can see it drop quite a bit.
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