Dyno, california gas and injector duty cycles
 

HI,

Has anyone running the newer California gas (more alcohol or whatever they are putting in it now as the subsidy for corn farmers) done a dyno where they were interviewing the computer during the dyno, specifically injector duty cycles, to see what percentage of the time they were open?

Just curious because after the last time they upped the % of whatever that crap is they are mandating be in our California fuel, my brother had to re-jet the carbs on his old mustang from 71s to 80s (yes 8 jet sizes) to get it to run as it did before the increased additives.

I'm just curious how close to max the stock fuel delivery system is if I run California gas, and I add 70+ Rear wheel HP.
My Current (changing almost daily) planned mods are:

3.5" true cold air intake
Maxbored TB from 75 to 80.5mm
ported and polished intake manifold
lower temp thermostat
Snow Stage II water injection
Killer Chiller (if not now, in a few months)
1.5 lb pulley (maybe, just to get the boost a little sooner)
removed middle resonators
CPU tune
a dose of some of that extra virgin snake oil (my secret weapon)

I am going to dyno and post my before numbers

Stock fuel system is not even close i think the first thing would be the injectors but Avos has shown these are good for at least 600+ at the flywheel. An yes the fuel your speaking of is ethanol and yes requires to be run at higher levels. Also burns cooler and makes more power but alot of things need to be changed in the fuel system an tune to run it. I do not think cali is making anyone switch but ethanol is added to standard fuel in small quanties. Not enough to make a huge dent though you will be fine.

They are requiring it to be mixed with the regular pump gas, now at a higher percentage. This is the 2nd time they are increasing the % mix.

I didn't know AVOS was running stock fuel delivery...that does answer my question, because I'm only looking to add 70-80 RWHP, and I think I can do that by simply riding your coat tails ;)

Well it’s pimped up a bit now, but just 80 rwhp extra with the twin-screw kit is nothing.

80 rwhp with the Eaton is another matter, as your engine needs more power to turn the supercharger to get to these levels, so 80 rwhp is 96 HP, and then you need to add the extra power from the Eaton, could be another 40 (or more) ... But 136 HP should still be feasible with your injectors and fuel with about 4% foreign matter.

I haven't seen anyone getting to 80 rwhp extra with the Eaton without tricks, but anyway good luck.

totally agree with Avos on this the twin screw is amazing and when I went to one on my old thunderbird supercoupe it was great. The roots is gunna take some work and its going to be remembering all the little things tht are gunna get us there. Little things such as porting of the inlet elbow, getting the intercooler situated, the tune perfect, making the engine as efficient as possible which the exhaust with all the lil tricks will help as well.

Boost as we all know is a measure of restriction in the engine, as the engine becomes more efficent the boost will lower but power will go up. Lets just say tht during this lil adventure I have seen my boost rise and when I would find a bottle neck it would lower after working on it, then power would rise. So now I start with increasing boost, porting intercooler n injector mannys, ported throttle bodies and redoing the inlet elbow, It may take a lil bit longer to get all the Ts crossed and the Is dotted but it will come not even worried.

If you have the money I say the twin screw is the way to go its better, more efficient, uses less power, can make more power, and looks cool. But its also very expensive to not only buy but as i have heard not all the bugs have been worked out. I myself am working on making one fit but as avos pointed out to me there are alot of little things to work out. Also there is no kit at all for the 98 to 99 xj and xk r's so until he gets that all done and from what I was told when I contacted Avos about it was he was working on it and had no timeline. Well not one to wait thts what started all this fun stuff with the twin screw kennybell an making the most of the roots. I have hit a few snags with the twin screw and have put it on the back burner for now. But one nice thing tht all this research, testing, trial and error, and such is doing is its letting all the bottle necks get opened up so the twin screw will be even more powerful.

You might try some of Newbie's extra virgin snakeoil ;-)

This is what I am currently planning on doing:

All figures I'm giving are what I think is reasonable for Rear wheel HP. For simplicity, I'm not commenting on torque, which of course is supremely important and will also improve with these mods.

I am going to do a before/bone stock dyno this week to set the baseline.
Please do comment +/- if you think my assumptions are reasonable or not
How I plan to use this extra power is only during short bursts, likely rarely more than 10-20 seconds (passing on the freeway, surprising people launching accross intersections with my "XJ8" the car is wearing the rear XJ8 badge tee hee) and not for 1/4 mile drag, and the car will never see the track, so the heat soak issue I think is somewhat limited for my purposes.

For now I'm just doing these add ons. As soon as my chickens start laying their golden eggs, which I 'm hoping is only a few months away, I may seriously look at the twin screw.

Guestimated RWHP Added:

+25 XJR-0220's 3.5 cold air intake dyno results +25 HP
+15 Maxbored TB from 75 to 80.5mm given this is generally accepted as the current bottleneck
+5 ported/polished intake manifold (I'm being very conservative here)
0 lower temp thermostat
+20 Snow Stage II water injection
+20 Killer Chiller (if not now, in a few months)
+5 1.5 lb pulley (maybe, just to get the extra boost back and a little sooner)
+25 Tune (again, being conservative)
0 removed middle resonators (just so I could hear some exhaust sound)
120 Is the total estimate if the above numbers are reasonable

If I truly get 70+ HP at the rear wheels with the above I will be quite satisfied...for now.

Your far off to be honest, but that does it matter, as long as you enjoy tuning your car it's already half the fun. I think it is already great that you want to do it in a controled measured way with dyno results in between, at least that will help the community on what is possible (or not).

I do enjoy the process of learning about this and making the tweaks to improve the car.

I must admit I am a complete newby at this....which is why this forum is so useful.


You wrote "as your engine needs more power to turn the supercharger to get to these levels"?? The HP gains I was talking about were not gained by spinning the supercharger faster, other than maybe a 1.5 lb pulley, but from:

+freeing up the intake side by, switching to a much less restrictive intake tube with superior bends, porting and polishing the throttle body and intake,
+getting a tune,
+very, very significantly improving cooling via water injection and Killer Chiller.


I understand you are of the position that the M112 is running at max efficiency, but the intake tube and manifold clearly are not, as XJR-0220 has demonstrated, and the 75mm throttle body is not, as it is generally accepted to be the current bottleneck.The results people are claiming with the Killer Chiller must be worth at least 15 hp, since they can be significantly felt, as well as water injection is reported to give a noticeable gain...how could one not gain significant power by upgrading and adding these items?? I really don't understand your logic. Please explain in detail. I trust that you do have far superior knowledge and understanding of these things than me (which would not be that difficult)

What is your opinion of what do you think these mods would give me, in RWHP terms? Do you think it would not add up to at least 70 additional RWHP? Your honest and knowledgeable answers are sincerely appreciated.

I'd like to know why, specifically, you think these mods would not add up to at least 70 RWHP? This makes no sense to me. Please elaborate.

I am happy to provide real dyno evidence of what gains I actually got, before and after, since it is nearly impossible to get an honest answer out of manufacturers.

Since XJR-0220 was using a dyno, and is not trying to make a business of selling product, I believe his numbers to be reasonably and reliably accurate.

Too strong for me makes my toes curl, my nipples erect and my car crap thunder and freebase nitrous haha

Since I am doing lots of research now, and am on a steep learning curve,

Question for AVOS, is there anyone near San Francisco, California that has one of your twin screw kits running in their car that I could ride in and have dynod. I'd be happy to pay for the dyno run of course.

Before spending that kind of money I would like to see one in action, on the dyno, and go for a ride. I'm sure anyone who has one of your kits would be happy to show it off to me...yes?

You can only make seriously more power by moving more air into the cylinders. Cooling after the supercharger will not allow for more air, but only reduces the ignition retard, so there you retain some power which would otherwise be lost. The mods to cool, become more important when you up the boost, or in other words, you can up the boost more with adding more cooling, and this is how you make/retain more power.

So far xjr-220 hasn’t shown any dyno slip we can discuss, but many have gone before you and xjr-220 to update the intake tube, so it’s not a 1st. Porting the intake elbow and blower also isn’t 1st, and the rest you can do isn't either, although I was the first to suggest boring the TB out with maxbore (whgere I have already made one, but still needs to be installed on a AJ26 engine).

Maybe in stock form the 80mm TB enhancement might not be so noticeable, but when you plan on moving more air, it becomes it obviously more noticable. I don't have a 90mm TB for show on my car, and for those that want to go further in power, I can also deliver a 100mm version even.

Attached are 3 dynos, although this type of dyno gives lower rwhp (due to the 2 small drums per wheel), the value of these are they were all made on the same dyno. Examine them and the mods I would say.

The numbers on the comparative dyno do NOT match the graphs. For the green line it says 336 max hp, but the line on the graph is closer to 375. Something is wrong with that pic. I also saw on those dynos where the car lost 2 hp after a full exhaust. What happened there?


I thought it was generally understood that all the intake, TB, porting and polishing mods DO move more air in...

Doesn't a less restrictive intake move more air in?

Less vacuum on the intake = more air, right? More from the intake tube, more from the TB, more from the ported polished intake. Doesn't more+more+more = MORE?

SO, if I understand you correctly, if the temps are lower because of cooling, then some temps are added back with say a modest 1.5lb increased pressure pulley, wouldn't that then be at a place with the same initial/stock temp, but with more air flow,O2 and therefore more power? I think it is safe to say that a meth/water injection kit will at least cancel the modest temp gains from +1.5lbs of boost. I know your beef with the M112 is its inefficiency and tendency to make lots of heat, but with the addition of killer chiller and meth/water injection, couldn't 50 RWHP be gained from the additional flow that the sum of these mods incrementally give? What about with the addition of porting and polishing heads? that is the same principle there too, and it is generally accepted that more air is moving in and out, even without a supercharger. Porting and polishing heads is generally accepted as yeilding substantially more power. I'm just not buying the argument that the M112 is currently the bottleneck on this set up.

It is starting to sound like you have PTSD from a bad date with an M112 ;)

Of course XJR-0220 is not the first to design a 3.5" intake tube, but his design does appear that it would be functionally better, with better bends where the air turns 90 degrees into the TB, so it does appear, at least to me, that his "is" better than what has come before. I think all these incremental improvements ought to each add something. I'm not saying he walks on water, just that he is applying the laws of physics and flow dynamics better than his predecessors.


I guess the only way for me to answer my questions is to try a few things and go back to the same dyno under the same conditions and just see what the results are.

Thank you for your inputs, your posts are always enlightening to me.

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Originally Posted by Newby (Post 527814)

The numbers on the comparative dyno do NOT match the graphs. For the green line it says 336 max hp, but the line on the graph is closer to 375. Something is wrong with that pic.

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You look at torque, they have scaled it differently.

Quote:

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Originally Posted by Newby (Post 527814)

Doesn't a less restrictive intake move more air in? Less vacuum on the intake=more air, right?

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Of course, and the more air you want to get in above stock, the more important it’s going to be to ensure you get as less losses as possible. But porting comes at a price, and hp per $ rate isn’t favorable. Easiest and biggest gain is to push in more air, if money is no object port the heads, and also install bigger valves.

Quote:

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Originally Posted by Newby (Post 527814)

Isn't it more O2 that matters most? and colder air has more O2, correct?

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Yes, if you can suck in cold air from the airbox you get more dense air, so more o2 molecules. If you suck in warm air before the supercharger, you can’t increase the O2 molecules after it anymore, you only decrease the volume a little; I hope you see what I mean.

Quote:

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Originally Posted by Newby (Post 527814)

SO if the temps are lower because of cooling, then some temps are added with say a modest 1.5lb increased pressure pulley, wouldn't that then be at a place with more air flow,O2 and therefore more power? I think it is safe to say that a meth/water injection kit will at least cancel the temp gains from +1.5lbs of boost.

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Probably, but 1.5 extra boost is not much, if you want 70, you need to go much higher, ie 17 psi or so (so 6 psi increase)

Quote:

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Originally Posted by Newby (Post 527814)

I also saw on those dynos where the car lost 2 hp after a full exhaust. What happened there?

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I haven’t been there, and 2 or even 10 rwhp I would considered within an error margin on the dyno anyway, so it could have been even more or less.
Let’s just say that I am also still using the stock exhaust…

Quote:

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Originally Posted by Newby (Post 527814)

Of course XJR-0220 is not the first to design a 3.5" intake tube, but his design does appear that it would be functionally better, with better bends where the air turns 90 degrees into the TB, so it does appear, at least to me, that his "is" better than what has come before. I think all these incremental improvements ought to each add something, but I do see your point. You need more O2 to match the fuel to.

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I don’t know what on the market, but the bends are not unique, and can also easily be made with silicon tubing (as how I did it in the past). The pipe does look good though, and is better than stock.

Quote:

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Originally Posted by Newby (Post 527814)

I guess the only way for me to answer my questions is to try a few things and go back to the same dyno under the same conditions and just see what the results are.

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This is the best approach, and indeed it is important to learn the Dyno, and make sure you always take your time to create conditions as close as possible to previous runs.

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Originally Posted by Newby (Post 527814)

Thank you for your inputs, your posts are always enlightening to me.

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No problem, but I am also just an enthusiast.

Please don't change thew text all the time, better to start a new post.

I'll wait for now before I respond again ;-)

Quote:

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Originally Posted by Newby (Post 527814)

I know your beef with the M112 is its inefficiency and tendency to make lots of heat, but with the addition of killer chiller and meth/water injection, couldn't 50 RWHP be gained from the additional flow that the sum of these mods incrementally give?

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Heat is just one enemy, the power consumption of the unit is the other one and is caused by the nature of design (boost + vacuum = power consumption). This is why the newer units (TVS) is already so much more efficient, they look more like screws now which have alleviated some of the power losses of the roots type, and then top of the line the KB units.

Quote:

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Originally Posted by Newby (Post 527814)

What about with the addition of porting and polishing heads? that is the same principle there too, and it is generally accepted that more air is moving in and out, even without a supercharger. Porting and polishing heads is generally accepted as yeilding substantially more power

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Although already answered slightly, if you have an unlimited budged of course you can get more out of the setup, porting of the heads have been offered for ages already on our cars (including of the intake elbow etc).

Quote:

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Originally Posted by Newby (Post 527814)

I'm just not buying the argument that the M112 is currently the bottleneck on this setup.

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It’s not so simple as that, everything counts, but you just can’t add up the hp you think you could gain as you did.

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Originally Posted by Newby (Post 527814)

It is starting to sound like you have PTSD from a bad date with an M112

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No, I just know where its limits are, the unit is a very good one for a certain application, although as said it is already at its maximum efficiency. So the yield (net power) will get smaller the higher the pressure, to a certain point where it doesn’t increase anymore.

Thank you for all your efforts in educating me.

Now I understand why I couldn't simply add the gains together necessarily.

I am learning so much...and so much more to learn...

I see what looks like a huge bottleneck in the exhaust manifolds and the cats, but I don't think anyone has made better headers yet. I'm not thinking changing the cats is worth it either.

I would like to see with my own eyes a twin screw on the dyno.

Until then I am going to follow the route of those who have gone this way before me with working on each component and continually chasing and improving the bottlenecks as they change from one to the next.

I see what looks like a huge bottleneck in the exhaust manifolds and the cats, but I don't think anyone has made better headers yet. I'm not thinking changing the cats is worth it either.


Thanks again

there have been a few tht have made headers buckland for one but price and what they will bring to the table is being awaited. I tried but could not get a nice set of equal length to fit.