Sam280Z Posted May 28, 2013 Share Posted May 28, 2013 Yep. I think we are saying the same thing. However, I am of the opinion that anything you can do to minimize the tau layer is worthwhile (in terms of making the engine easy to tune). You can, with the right algorithms, compensate for any tau layer. The problem is that there is no *direct* way measure it. You have to put in compensation parameters (which change with engine speed and manifold pressure) and see if the engine behaves as expected. If not, adjust the parameters and try again. Go search "EAE" at MSExtra.com and read about all the fun people have tuning acceleration enrichment.You also have to have your VE table tuned spot on first, but the unknown tau behavior affects your ability to tune that. it's a bit of Catch-22. I just went through this on my motor. I read up on injector placement on the TWM website and other places on the web. Everything focused on the effects of placement on HP. I even knew that Joel had moved the injectors to the head on his stroker turbo to solve idle and transient tuning because I own that engine as well. I thought I would be able to tune around whatever issues Joel had because I was using MS3 as opposed to the old TECII. I built the motor with 63 lb/hr injectors in the TWM throttle bodies 7 inches from the intake valve. I drove and *attempted* to tune it for over a year before breaking down and installing smaller injectors in the stock location and using staged injection. This has made the single largest difference in tunability of anything I have done. Transient/tau tuning has become an afterthought in the tuning process as opposed to the driving factor. The build in question will almost certainly not have the same level of tau/tunability issues that I had with mine. But small efforts to reduce the effect of the tau layer will be, IMHO, time well spent. Sam Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 29, 2013 Share Posted May 29, 2013 It's what keeps drivability engineers employed for the OEM's. Break down the base code for the EFI systems, and you will see the basic map is VERY simple (it's why MS1 was so nice...) ALL the complexities come in partial throttle transient response. Once you get to a certain level, the ease at which a staged injection comes into play starts making sense. If this is going on a 300 HP engine, the amount of fuel, and injector placement will be totally different than one for 750HP. Ask Jeff P about tuning 72# injectors in the stock location... Quote Link to comment Share on other sites More sharing options...
madkaw Posted May 30, 2013 Author Share Posted May 30, 2013 I appreciate the input Sam. Without even knowing much about the Tau Layer I was trying to find the best injector set-up to get the fuel in the right spot. I have been researching injectors for my manifold and I am interested in the type injectors that shoot at an angle. Actually, I didn't even realize this type injector existed, but my knowledge of FI is very limited. I haven't had much luck trying to find an OEM application that will fit my needs. Most listings of injectors give all specifics for the injector-Except spray angle? What I am hoping to find is a high impedance 30lb -14mm injector that shoots at an 35 degree angle. I have been considering going to an injector shop and just asking them to match me up with a specific injector for my needs. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted May 30, 2013 Share Posted May 30, 2013 (edited) I feel your pain. Look for an injector that came on a single intake valve engine. It will have a narrow spray pattern. Wide pattern injectors are for hitting two ports/valves. Disc style tend to be better at atomizing than pintle. What are your HP goals? What EMS are you going to run? Edited May 30, 2013 by Sam280Z Quote Link to comment Share on other sites More sharing options...
madkaw Posted May 30, 2013 Author Share Posted May 30, 2013 Plan on running MS 2 3.57 HP is maybe 200 flywheel on my L24. Probably going to build a 3.0 and get above 250hp soon enough. So later injector spray patterns are wider for 2 valve intakes? Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted May 31, 2013 Share Posted May 31, 2013 Turbocharged or NA? I'm not as familiar with MS2, but if you are thinking of going sequential, you can go a bit bigger on the injectors and likely find more options. The key is keeping the idle pulse width high enough (>2ms) (higher is better). I'd seriously consider MS3 or even MS3pro. Expandability is built in. Beleive me, once you get started tuning, you'll want all the options. If you're going turbo, I'd look into staged. You can buy 1990-2000's 19lb mustang injectors by the fistfull cheap. That's what I'm using for my primaries. I'll PM you my # and if you want to discuss, you can call me sometime this weekend. Sam Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 31, 2013 Share Posted May 31, 2013 Really with stock injector placement position, you are not really "needing" staged injection until you are over 50# injectors, and that's some serious horsepower. Over 60# injectors JeffP's turbo engine started getting the idle issues people complain about (low PW at idle... etc...) The stock turbo injectors will give excellent idle, and more than enough fuel flow to run the HP you are shooting for. I think they are around 24#, the N/A's are around 17-19# something like that. They will be narrow shot as well... Quote Link to comment Share on other sites More sharing options...
madkaw Posted May 31, 2013 Author Share Posted May 31, 2013 For now, this intake will be on an NA motor. Since am making the transition to MEGASQUIRT 2 on a 1971 I will be starting from ground zero. I plan on installing the MS2 and running COP on my motor now to get started learning about engine management. I am ASSuming that my intake will be suitable for NA and Turbo eventually. I don't want to jump right into a pressurized scenario at this point. Besides, I am still having fun with NA and want to build a bigger motor and run it with MS. For now, the MS will be running my L24, so injector sizing will be in order. I have read what you have stated above Tony. I have no 'stock' injectors -per say- so I was shopping for what will do the job cheaply, but hopefully in the high impedance 14mm size Quote Link to comment Share on other sites More sharing options...
madkaw Posted July 25, 2013 Author Share Posted July 25, 2013 Okay guys, starting to get serious about this intake. I am in the process of trying to finish fabbing the plenum and need to decide on my TB. I guess what I really need to establish is size. I want to size to cover all my applications which will be 2.5 liter to 3.0 , NA and Turbo. I have read that going to big is a no no and not necessary - especially for the limits of my HP goals( 350-400 max) I thought 70mm would be plenty- any thoughts? I am probably going to just order an EBay universal application type. One reason is that most of those come with a base plate for me to weld on and I won't have to fab. Prices are around 100$ for a new unit with base plate. Quote Link to comment Share on other sites More sharing options...
madkaw Posted July 25, 2013 Author Share Posted July 25, 2013 http://bit.ly/1455rTN Above is a link to the eBay ad Quote Link to comment Share on other sites More sharing options...
roger280zx Posted July 27, 2013 Share Posted July 27, 2013 I would say 60 would be enough, and they're 25 bucks. Quote Link to comment Share on other sites More sharing options...
madkaw Posted July 27, 2013 Author Share Posted July 27, 2013 25$ at the pick n pull I'm presuming . Then I would have to fab a plate for the intake to mount the TB. 240sx? 70mm to big you think? Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 28, 2013 Share Posted July 28, 2013 (edited) JeffP is pumping 700+ through a 60mm, for a time he tried a 65, but went back to 60, and is considering one of hose 55mm units out here on Nissans...the tip-in can be an issue. He won't go cable, so an asymmetric cam on the TB is out. The 60mm should be fine turbo, and at MAX a 65 in NA on a plenum s style manifold in the 300hp range for proper modulation off-idle. Without a serious asymmetric cam and throttle cable setup the 70mm is tip-in hell... Drag Race only. And there's no practical advantage at WOT... Save yer money! Edited July 28, 2013 by Tony D Quote Link to comment Share on other sites More sharing options...
madkaw Posted July 28, 2013 Author Share Posted July 28, 2013 I wasn't shooting for the biggest I could go . I have read that too big will cause the tip in issues like said, and my engine won't flow enough for anything bigger then probably a 60mm. Money wise, I thought 100$ was decent for a new unit that already had the mounting plate made to weld to my plenum. A few bucks more to save time and aggravation of machining out a mounting plate. Not sure about the reason of cable or no cable linkage. I thought cable was the only option. I did find some 65mm units on eBay, but that's about as small as I found for these CNC versions. I will continue to look at OEM versions. Thanks for the input guys. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted August 3, 2013 Share Posted August 3, 2013 What is tip-in? I was running a 70mm tb on my car. It had a big plenum and big runners. It seemed to work well. Quote Link to comment Share on other sites More sharing options...
madkaw Posted August 3, 2013 Author Share Posted August 3, 2013 What is tip-in? I was running a 70mm tb on my car. It had a big plenum and big runners. It seemed to work well. Glad to hear the 70mm is working well for you. Can't tell if your serious or not with the Tip-in comment, but I am guessing you are not having any drivability issues with your set up. No issues easing into the throttle or any transitional throttle issues? 70mm is overkill from a math standpoint based on engine size. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted August 4, 2013 Share Posted August 4, 2013 I seriously don't know what tip in is. I'm guessing it's a side effect of a large tb? Quote Link to comment Share on other sites More sharing options...
madkaw Posted August 4, 2013 Author Share Posted August 4, 2013 I seriously don't know what tip in is. I'm guessing it's a side effect of a large tb?Exactly. Modulation at the tip in of the throttle gets harder to control because even a slight throttle increase of a large TB is letting in a lot of air. Not a problem if you are always flooring it:) but as a daily driver might be hard to dial in .That's why I asked about the driving characteristics of your car. What TB are you using? Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 5, 2013 Share Posted August 5, 2013 Look at the modular Fords. Same engine in Mustang and Expedition. (Discount fly by wire now, I mean before...) The Expedition has a HUGE throttle body, gives the impression that the hog is jumping when you feather touch the throttle, same TB in a lighter weight Mustang would be much more jumpy...so they seriously downsize the TB size to allow easier modulation in daily driving. It's real, watch an old 3.8 mustang jump from the line compared with a 4.6... But halfway across the intersection the V6 goes "waaaaaaaaaauuuugggh" and leisurely accelerates. The V8 though pulls. If you never ran them more than 1/4 throttle in 30 foot sprints the 3.8 V6 gives he IMPRESSION of being the more powerful car. Same as the big throat TBs MSA sells. Does absolutely nothing for power, but gives the impression there has been an increase. With a lightweight flywheel, metallic clutch, the tip-in can be annoying. Frankly the best TB made for the Z/ZX was the progressive unit on the Fairlady ZX, either a dime or nickel sized primary, that took 3/4 throttle to open fully, and which would hold the Carr all day long just under cam peak torque (meh, 3500 at least)... In the next 1/4 throttle the secondary plate went from 0-90 degrees open. That TB on a turbo car makes or GREAT On-Boost modulation, and in a temperamental N/A car makes moving from a stop pretty easy as well. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted August 5, 2013 Share Posted August 5, 2013 I wish I had a jumpy throttle. Either the turbo or the low compression prevents that. Quote Link to comment Share on other sites More sharing options...
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