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Originally Posted by BDC
(Post 8899366)
I just fussed last week to get the thing welded on. Now you're ruining my day. :)
One thing I did consider was finding an aftermarket BOV whose output goes back into the turbo inlet duct ala stock. The thing w/ the clamps and coupler is a terrific consideration!! I thought about it earlier when I had problems getting a clamp on. However, and this is a guess, anywhere there's a coupler there's pipe that's been beaded with the clamp on the opposite side. Perhaps I should swap to T-Bolt clamps? B Good idea to have some lugs welded on either side of the joins then use a alloy strip to physically bolt the joint together, good safety thing. The silicone joins you have at 30 odd psi will start to balloon a fair bit so you may need another hose clamp in the middle to support them (you will see it on dyno). Keep an eye on BOV and look for traces of stuff coming out of it, but you will pick it up when you dyno the car anyway to see what vapor does come out of it, you may be ok??? |
Well if you want to compare properties of the different fuels instead of writing down all the specs, I will refer you to the page where they discussed that here.
https://www.rx7club.com/auxiliary-injection-173/ai-injectants-scientific-properties-comparison-597931/ You can very well see that gasoline or petrols latent heat is WAY less than that of Methanol and the same goes for its cooling properties. And the energy that it releases is higher too. Dont get me wrong, I know that you can do it with gasoline but is not the best way. Maybe the cheapest yes, I dont know. |
Originally Posted by lzamboni
(Post 8900395)
Well if you want to compare properties of the different fuels instead of writing down all the specs, I will refer you to the page where they discussed that here.
https://www.rx7club.com/showthread.php?t=597931 You can very well see that gasoline or petrols latent heat is WAY less than that of Methanol and the same goes for its cooling properties. And the energy that it releases is higher too. Dont get me wrong, I know that you can do it with gasoline but is not the best way. Maybe the cheapest yes, I dont know. Think outside the box :) The old boys from almost 100 years ago did. |
Well in that case running way richer like you say it might do the trick but I am still not completely convinced since that takes care of the temperature drop but not the total thermal energy of the fuel and the fact that Methanol has a higher ignition point so that gives an extra little safety factor.
On the other hand I am with you in the sense that almost everything you see nowadays has been tried and used long, long time ago. There is almost nothing you can do or try today that hasnt been tried or experimented with or even used for long time before. ( Talk about aerodynamics! Today everyone wants to have a car with spoilers or wings but Mr. Kam if I am not mistaken invented the most basic rear wing in around 1950's? And he did a complete aerodynamic body package on his car that had better Drag coeficient than any road car today. But no one cared since the gas was so cheap they could get away from the aerodynamics problem by using bigger engines) But that is not the point here, even if this has been used for ages, its still something not of the popular knowledge and mainly experimented by high end users ( race car tuners, etc. ) and what is being tested here should be something to help the rest of the people that haven't heard or didnt have the time, means or guts to experiment on their own. I surely am getting some insights into this topic I didnt have before even though I knew all the basics of AI. |
Took a quick look at the logs in an attempt to gather data on rise of IAT's with boost. Using the current 80/20 ratio of gasoline to methyl alcohol at 15+psi, the IAT's are rising 2* per psi of boost increase starting around 75-77*F. By 22psi, they've risen 15* to settle at 92*F.
Tomorrow I'll try removing 5% more fuel and thicken it up to a 75/25 and re-try these same tests with the same AFR's in the mid 10's:1. Curious to see if EGT's drop as well. Also going to add 1* to leading advance while keeping split at 8*. B |
What's the stock readings of WOT IAT on a t2 engine? Anyone know?
I'm just curious... |
Brian that is pretty damn interesting.
As a guy who does R&D work every day tho, I feel like you really need to compare apples to apples to prove anything. I'd like to see a set of datalogs from the same car with and without a properly sized intercooler. I've been thinking about throwing my car back together for a while before I send you my parts to be balanced, maybe I will put the AI system together and do a run with and without my intercooler on the same day and see what my logs look like. The only problem is I just bought an airplane, so my time and $ reserved for projects is way low right now.... If I get a spare weekend I'll do some tests and post the logs. Otherwise keep doin what youre doing, it looks like a sweet setup! PS. youre gonna catch some flak for that inlet ducting - I used to have my radiator hoses wrapped in aluminum heat tape and everyone always got this look on their face and said "whats with the tinfoil?" |
Originally Posted by BDC
(Post 8900583)
Also going to add 1* to leading advance while keeping split at 8*.
B Meth magic :) |
Originally Posted by patman
(Post 8900792)
"whats with the tinfoil?"
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Originally Posted by classicauto
(Post 8900795)
So a total IGL of 16* (over 15psi) after those changes?
Meth magic :) B |
Originally Posted by patman
(Post 8900792)
Brian that is pretty damn interesting.
As a guy who does R&D work every day tho, I feel like you really need to compare apples to apples to prove anything. I'd like to see a set of datalogs from the same car with and without a properly sized intercooler. I've been thinking about throwing my car back together for a while before I send you my parts to be balanced, maybe I will put the AI system together and do a run with and without my intercooler on the same day and see what my logs look like. The only problem is I just bought an airplane, so my time and $ reserved for projects is way low right now.... If I get a spare weekend I'll do some tests and post the logs. Otherwise keep doin what youre doing, it looks like a sweet setup! PS. youre gonna catch some flak for that inlet ducting - I used to have my radiator hoses wrapped in aluminum heat tape and everyone always got this look on their face and said "whats with the tinfoil?" B |
Originally Posted by Dudemaaanownsanrx7
(Post 8900267)
It's funny to see the AIT temperatures INCREASE as the throttle is closed. it's a bit backwards then what we're used to seeing.
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Jan 22 '09 Update
Hey folks, went and put another 30mins of seat time in the car. Took 6 more datalogs. I shifted 5% more fuel load from gasoline to alcohol and added 1* Lead advance at higher boost (20+). Ambient air temps today are about 81-84*F here in DFW. The purpose of today's experiment was for a few things:
1. See if the IAT's at the same boost pressures are proportionally any higher today compared to yesterday per the increase in ambient air temps 2. Record data for positive changes in EGT's when running a 75/25 ratio of gas to alcohol (as opposed to 80/20) when targetting the same AFR's compared to yesterday 3. See if the engine would knock with the 1* Lead advance as well as produce any lower EGT's To answer those questions: 1. Doesn't appear to be any unless it's very minimal. The IAT's remain the exact same. I'm curious to see what a drastically colder day or hot summer day here in Tx would yield but the more I stare at this the more I believe they will not shift from where they are now. At 15psi of boost, the IAT's settled down to 77-80*F or just a hair below ambient to my surprise. I did notice that with this heavier alcohol the IAT's had a tendency to continue dropping ever-so-slightly at 15psi. At 21psi, they settled at 90*F. At 22-23psi, they settled about 92-95*F. The same trend applies: No matter how long I run it, the IAT's remain constant with respect to the boost level. You can practically dial your watch around it. The change from 80/20 to 75/25 I don't believe produced any more IAT cooling effect. 2. Definitely a difference when I got the target back down to low-mid 10's:1. On one run at ~20psi of boost, the AFR leaned out from mid 10's to 11:40:1 by 7krpm. The EGT's got to about 1720*F. I'm still trying to correct the base fuel map to get this part straight but when I richened the alcohol to get to low 10's:1 the EGT's dropped dramatically back down to mid 1600's. This is seemingly counter-intuitive to gasoline tuning as with everything else remaining constant the opposite effect should occur. The switch over from 80/20 to 75/25 yielded lower EGT's by about 70-80*F from what I can see. That's significant. It leads me to believe that when leaning over to more and more alcohol (even switching to it in the first place) means that a target AFR should move down. Naturally, going from 80/20 to 75/25 today means that to hit the same "target" AFR to yield equivalent EGT's should move down (or richer) in the scale. As it stands now, I'm aiming for low 10's but may need to go for 10 flat:1. Perhaps someone who's more experienced w/ lambda and how wideband sensors read different types of fuel can elucidate more on this. 3. Can't say for certain. Ran 23lbs today in 3rd and 4th gear. Feels around 500rwhp and 400ft/lbs torque but obviously I don't know til I sit on a dyno. I tried topping it out past 7krpm but kept letting out early according to the datalogs. The tach is reading higher at high RPM than actual RPM. The highest I got was 7000rpm exactly on a couple runs. I want 500rpm more. I'll have to just do it again. One thing I did notice on an uphill, 4th gear run was the boost "locking" itself around 10-11psi. The w/b was below 10:1 and I believe the EGT's were cold enough to slow the turbine's acceleration rate. Once I ran some more RPM and the AFR's leaned out, it "unlocked" and shot up to past 20psi. Plans for next session: Correct the base fuel maps that are steadily leaning out at high RPM to see if I can keep a more stable EGT as well as figure out exactly AFR's are needed for this ratio of gas to alcohol. Datalogs below. I'd like some input on some of this if anyone has light to shed, please. Also verified that the EGT to +5VDC conversion is a 0*F to 1800*F scale where 1800*F = +5VDC. 4.80VDC 1728*F 4.70VDC 1692*F 4.60VDC 1656*F 4.50VDC 1620*F 4.40VDC 1584*F 4.30VDC 1548*F 4.20VDC 1512*F 4.10VDC 1476*F 4.00VDC 1440*F B |
Jan 22 09 Datalogs
Datalogs BDCHA21-25. I can't recall which runs are 3rd and 4th but those that cut off in the 5krpm are 4th. You won't find me topping 4th gear out in this car on a highway; no way in the world. This needs to get on a dyno pretty soon as it's becoming dangerous to drive. The rear-end got a little loose at the top of 3rd on a high boost run.
BDCHA21 http://bdc.cyberosity.com/d/14107-1/bdcha21-1.jpg http://bdc.cyberosity.com/d/14109-1/bdcha21-2.jpg http://bdc.cyberosity.com/d/14111-1/bdcha21-3.jpg http://bdc.cyberosity.com/d/14113-1/bdcha21-4.jpg BDCHA22 http://bdc.cyberosity.com/d/14115-1/bdcha22-1.jpg http://bdc.cyberosity.com/d/14117-1/bdcha22-2.jpg http://bdc.cyberosity.com/d/14119-1/bdcha22-3.jpg http://bdc.cyberosity.com/d/14121-1/bdcha22-4.jpg http://bdc.cyberosity.com/d/14123-1/bdcha22-5.jpg |
Jan 22 09 Datalog BDCHA25
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Originally Posted by BDC
(Post 8901790)
I'm still trying to correct the base fuel map to get this part straight but when I richened the alcohol to get to low 10's:1 the EGT's dropped dramatically back down to mid 1600's. This is seemingly counter-intuitive to gasoline tuning as with everything else remaining constant the opposite effect should occur.
B |
^ The MORE fuel you run *of any type* the far colder the EGT will be ;) Its only a myth perpetuated by ignorant types who have never had a car sensor'd up that push the "richer = higher EGT" CRAP :)
Keep it rich IF you want your turbo and your cars engine to live is my advice to you. DON'T fuck around with your IGN timing in an attempt to reduce your EGT *free bit of advice for today* it will only make you detonate your engine! The excess fuel ratio is of far mare greater importance here and always will be. I will link you to some good threads on this if you are interested>>>>? |
http://www.ausrotary.com/viewtopic.p...st=0&sk=t&sd=a
http://www.ausrotary.com/viewtopic.php?f=4&t=158437 Have a read ;) http://www.youtube.com/watch?v=VQ7gF...eature=related ^ This is how professionals keep EGT in check ;) I have engineering data on every single F1 engine made from 1977 to 1988 (all turbo years) and how they were tuned and ALL apply the same methods fro controlling EGT :) you would be wise to learn of these people rather than some others :lol: 50% excess over stoich is the norm........... and it is ALL about EGT control, nothing else. You will find the same will apply to you ;) |
Originally Posted by RXHEAVEN_WA
(Post 8902295)
50% excess over stoich is the norm........... and it is ALL about EGT control, nothing else. You will find the same will apply to you ;) Now the question I have is this -- What's a truly safe EGT range when under load? I was under the assumption it was more like 1550-1600*F for most reliability, 1640*F for best power, and above that it's risky. B |
Originally Posted by BDC
(Post 8902330)
I wholeheartedly agree with this. This is the same conclusion I've come up with -- AFR's, IAT's, all of that and all the acronyms in the world are contingent upon EGT's. It's the reason why I am flexible on AFR stuff and not sticking to some seemingly arbirtary ratio like 11.5:1.
Now the question I have is this -- What's a truly safe EGT range when under load? I was under the assumption it was more like 1550-1600*F for most reliability, 1640*F for best power, and above that it's risky. B 900deg C will require a mixture of around 10.0:1 to 10.3:1. The thing though with EGT to remember is its a function of power as well, so the more power you make and also remember the more heat retained by restrictive exhaust housings etc the harder it is to keep down too. If you are interest in how EGT varies with AI ratio and AFR you can read this report http://www.riceracing.com.au/resourc...rinjection.pdf (Note FAR is 1/AFR). It is not as simple as it seems, but you can note critical drops in temperature in other parts of the combustion chamber at various measurment points *even if EGT does not fall in relationship you expect*. Heat is one of the most complex things to understand in mechanical engineering. http://www.youtube.com/watch?v=VUWCo3lDjH8 ^ You watch what I mean about EGT stabilizing over time........... |
Interesting read! I think I'll give some of that a try and pull spark out of the leads.
B |
Originally Posted by BDC
(Post 8902386)
Interesting read! I think I'll give some of that a try and pull spark out of the leads.
B |
Originally Posted by RXHEAVEN_WA
(Post 8902431)
If you want some more advise keep you split relationship at 8 deg minimum (I would use 10 deg personally on that or more, especially with the amount of advance you have).......... I don't know what plug you have but I would run an 10 heat range or colder.
I'm using 8* split and will probably stay with it but I think I'm going to pull Lead advance way out especially after reading some of the stuff on ausrotary.com about it. The idea of running static advance from 15psi to 30psi never made any sense to me yet it's something that's common over here. It's always bothered me in the back of my head since either there's too little advance at 15psi or there's way too much as boost continues to rise. Afterall, we're cramming more O2 molecules into the engine to produce more power per stroke -- it seems to me that (principally) the denser we make the charge the later we should fire it off. Am I off or are my instincts here correct? B |
Originally Posted by BDC
(Post 8902486)
I'm still running 9's but am considering moving to a 10. Was just asking about that earlier today as a matter of fact.
I'm using 8* split and will probably stay with it but I think I'm going to pull Lead advance way out especially after reading some of the stuff on ausrotary.com about it. The idea of running static advance from 15psi to 30psi never made any sense to me yet it's something that's common over here. It's always bothered me in the back of my head since either there's too little advance at 15psi or there's way too much as boost continues to rise. Afterall, we're cramming more O2 molecules into the engine to produce more power per stroke -- it seems to me that (principally) the denser we make the charge the later we should fire it off. Am I off or are my instincts here correct? B I use a Trust NGK manufactured Single electrode (Platinum Ground and Iridium Centre) plug in all cars and the difference is universally acknowledged as "amazing" 10 heat range will work in fuel only, or AI and fuel cars at rich ratio's. The plugs will probably last longer than your engine (no disrespect intended!) High 750bhp engines run them for over 5000km and they come out as new (as guide for you). But my main point is the fire all of the time, and you will have allot more power and a much smoother one as well..... could even turn it into a wheel spinning monster ! Here is a link to the plugs I highly recommend you buy (don't worry about the cost, as it will be the last set you will need) http://www.rhdjapan.com/jdm-low/TRUS...tary-13B-13926 |
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