Gollum

Wow tony, do you know something about compressors or something? It's almost as though you do this stuff for a living.... 28-2900 sounds a lot closer to what it should be for boost threshold for your setup, but I'd say you should be able to get it even lower than that with simple tweaking. Lower the backpressure with a 3" downpipe with 45 degree bends instead of the stock 90 and run 3" all the way back while you're at it. And make sure it's done with mandrel bends, not crush bent as a 3" crush bent is more like 2.5" mandrel bent. Run a straight through muffler. It's going to be loud. Deal with it, it's a damn turbo car, be proud of it. Then run as close to rich best torque as you can get, even a bit extra if you can down low off idle for WOT. Fight detonation with as much heat management as you do spark management. Detonation is directly related to heat in your air charge, be it from chamber temp, ambient temp, or compressor outlet temp. Get temps under control and detonation follows suit. This will allow more aggressive timing, and faster spool times. If you have your exhaust manifold out, port it. Port it. Port it. There's lots of excess meat in there that can be smoothed out and not just help overall flow, but direction of flow into the turbine. If you want to get fancy, add water/meth injection for WOT use. Not only will it massively bring down charge temps, but it will add volume, and thus mass, to your exhaust charge, exerting more force on the turbine wheel equating to faster spool. I've noticed switching to E85 can have as much as a 10-15% reduction in boost threshold for a given setup. Water/Meth can have similar results. Quick story... I took a ride in one of my best friends STI soon after converting to E85. We went for a spirited run and were taking a u-turn to head back. The light we were at was 2 lanes each direction and we'd been stopped at the light. He puts it in 1st, pulls away from the light casually getting up to about 2,500rpm at MOST, drops to 2nd, mashes the throttle, and snaps the clutch all in one quick smooth motion. The car almost INSTANTLY slid ALL FOUR WHEELS and we went sideways a full lane plus! Yes... a 2.5 liter made enough power with a stock STI turbo to move a 3500 pound load sideways, overcoming the traction of 4 wheels with limited slip, all while coming off of NO LOAD!!!! Turbo lag my arse. And that turbo isn't even ball bearing. It's single scroll. The only reason it can do as mentioned above is that it is pretty much DONE at 500hp, a mere 200hp per liter. The other benefactor is that it was E85. There's also a third, often overlooked, factor in this scenario... everything was STOCK, and therefor WELL MATCHED as a SYSTEM. Stock intercooler, stock exhaust manifold. He was running larger exhaust turbo-back too. I've often felt that a well prepped L28 with a T3 should be able to reach 1psi in 1st gear by 1750rpm. It just takes the right setup. And I also understand that a setup that does that probably won't reach over 350whp very easily. But who cares? When I finally get my S30 back on the road my goal in the first year is just 250whp with a 2300lb curb weight with a full tank. That's more than enough for my stock brake calipers and rotors and tiny 215 treads. Eventually I DO want to build a 500whp monster, but I also want to do it with a setup that nobody else I know has done. We'll see if I ever have the money for it though, and if I still want to once I do have the money.

He's very right. First time I saw this thread my first reaction was "15x10 doesn't fit" then I played around in my head and realized you didn't specify tire size, but rather rim size and figured out that there was a chance you cared more about rim width than tire width. There's nothing "wrong" with the stance crowd, hellaflush crowd, or what ever crowd you'd not like to be associated with, but for the most part that's just not us on this site. Most people here would ask questions like "How did you fit a 255 tread tire in the front of your S130?" Because that's who we are. The people that care about style or looks above performance are few and far between here. Thus, since we're so performance oriented, when someone asks if a rim fits we care more about teaching you to fish, not just giving you one. We want to make sure you understand how to measure clearances since rim clearance is JUST the beginning of wheel fitment. And by the way, a 9.5" rim is plenty to fill in the front with more tire than the well can handle. 9" works perfectly imo.

One of the best cams to use in a turbo setup is the early "a" cam, though I don't have first hand experience, just plenty of the gurus here saying so. My point isn't to go find that cam, but rather that using an OEM cam isn't going to kill you or matter all that much. The factory ECU won't run "as well" as it would on the factory cam, but who cares? Right now you just want the thing running, I get that. A NA cam isn't going to make such a huge difference you'll be in danger of breaking something. Just be careful before doing any WOT pulls. Get a wideband on it, even if you have to borrow one, to find out what it's doing under part throttle and low load, and slowly work up the throttle and load once you know it's safe. People have gotten 300+ hp out of the factory ECU, and I'd love to get more just to prove it can be done. Is it "optimum"? Hell no. But if you went back to the 80's nothing was optimum by today's standards.

Hey Wes, I don't know how I never saw this thread, but great work! I'm also in Vacaville and though I don't really have a whole lot of time to actually help with much I'd love to come check out the car sometime. Keep up the great work!

Have you ever tuned E85? With ethanol it's almost impossible to foul plugs and you don't lose power from being too rich like petroleum. Even though stoichiometric for E85 is around 9.7:1 it's max power windows is HUGE. For example, max power for pump gas is usually a window between 12.5:1 and 13.3:1. That's less than a 1 point window to hit. Anything from one side to the other and you can almost guarantee you're losing power. With E85 (not just straight ethanol) that window is from 6.9:1 and 8.5:1. That's over a point and a half difference and much richer ratios. If you scaled this up to look at the % differences you'll see that ethanol has THREE TIMES the rich/lean happy window for max power. So, in conclusion, though cylinder to cylinder consistency might be crucial with gasoline, it's much less crucial with E85. Just run extra fuel and you'll be okay. Yea I wasn't actually expecting you to jump on that, just toying with you.

I'm sure you could also find a AZCAR manifold to run this puppy and fret not about compression: http://www.summitracing.com/parts/qft-ss-650-e85/media/images Just about the perfect CFM for a E85 powered L motor imo.

double post.... browser doesn't like the new forum apparently...

I think you should just throw it together and add a wild cam that doesn't really come alive till 4,000. If you can spare it, have a good dynamic balance done on the crank so you're not freaking out each time you rev it past 7,500 and just plain out run the detonation. You're not looking to get 300hp from this thing, just 200. It might not do well in an endurance setting but I doubt you'll ever push it that hard. And even if you have to give up %5 of total power due to dialing back the timing, well I don't think that's the end of the world for your goals. The worse that could happen would be that it's SO prone to detonation that you only end up with 150ish at the wheels from pulling timing. Then that just leaves you at a starting point. Then either megajolt it, or re-ramp the dizzy so you can pull timing down low and bring it back up once the wild cam kicks in.

Hmmm... maybe a Java issue? I checked and both IE and Chrome are seeing 1.7.0_09 which I believe to be the latest.

I'm still not able to enlarge pictures. Seems to be just a chrome issue for me. IE9 enlarges just fine. My specs Windows 7 Ultimate SP1 64 Bit Chrome Version 23.0.1271.64 m Need any other info?

All things considered, it's probably designed around the N42 head. The question is, what's the compression actually going to come out to? You don't design a radical piston for pump gas compression levels... But maybe it WAS designed for a stroker and you can keep it moderate by using a shorter stroke.

Or if the subie has a tow hitch just tow it home with a car dolly. I've seen worse done. Rayapp used to tow S30s with a 280ZXT 2+2

I just heated some tie rods out. Amazing what just 60 seconds of a torch can do. I whacked for about an hour, then decided since I was going to reuse the tie rods, just heat'em up. Heated on side and it came off with two good whacks. Did the other side under 5 minutes... Then had a beer to lament over the hour wasted.

Or do what I did after doing 5 different brake bleed jobs, get a mityvac! Worth every penny. The only issue I have bleeding now is air entering at the threads of the bleed valve, which is easily fixed with some teflon tape.

I've wanted to do a high MPG 4 cylinder swap into my 280ZX daily driver, but honestly the biggest road block I run into is that most of the ones I like spin the wrong direction. And as tempting as the TDI swap is, I'm not so sure it makes sense to convert a chassis from gasoline to diesel just for RWD capability or even just overall love of the chassis. I think I'd sooner just buy a TDI. If it's about doing it just because, well that's fine. For me, if high MPG was the end goal but I still wanted solid power, my choice would be a turbo B16 honda. The CRX I owned with a NA B16 could reach over 40mpg and would average 35 combined with me flogging on it pretty much always. Add a turbo for some extra grunt when needed and it'd be a pretty potent combo.

I have seen blow through MAF setups run, but I'm not sure if you need a specific type of MAF to do it correctly. Idealy you want it to be post turbo so that your temperature readings are accurate. That said, the Z31 ECU is calibrated to run a MAF that's pre-turbo, and I'd suggest doing it that way just to keep the ECU happy. You're already running a hacked together setup (and I mean that in the most honoring way possible) mix matching an ECU on an engine that it was never designed to run, running non-stock sized injectors. There's all sorts of confusing already for an non-programmed ECU. To then throw in strange MAF readings for it just makes it worse. All that being said, I'm glad you have a wideband and I support experimentation. Before the days of tuneable ECU's we made do with what we had available, and I still support that notion whole heartily. I say, make it work and then let us know how it went and what you did.

Well I don't think I ever once really disagreed with YOU, just semantics which makes for good talking points. What you say is true. If you have a fixed curve and you have to pull back timing because of pinging at peak torque you're probably losing some power up top. Not ideal, but that's the world with points and simple vacuum/mechanical advance. I'd argue that non computer controlled ignition can still be VERY effective, but I'll be the first to admit it's really not fun when it comes to force induction. And I've also been wanting to point out (since I ran out of time earlier a few days ago) that a motor's combustion properties should really be designed around a specific fuel range. Back in the leaded gasoline at the pump days, muscle cars saw VERY high compression ratios, even by today's standards. These motors were designed around a specific fuel's abilities and when leaded fuel became banned and/or unavailable, manufactures had to design for a completely different fuel. They had to lower compression ratios and change distributor weights/advance curves. Let me stress this point, I'm not angry this is what you do in engineering, you design parts to work as a SYSTEM for a given APPLICATION. This doesn't make either motor setup right or wrong. If you want to run race gas, design accordingly. If you want to run pump gas, design accordingly. Don't design a motor that should run on race gas and then complain that you're detonation limited on 87 octane. That said, I run my L28ET on 87 octane. Yes I'm under 10psi, but I'm also un-intercooled. I personally feel this is the big mistake with flex-fuel vehicles. Any E85 running vehicle in NA form should have AT LEAST 13:1 compression as a MINIMUM. If you had someone like Honda design a E85 only S2000 they should easily be reaching 15:1 if not higher compression. But why haven't they? They don't want to design all new cylinder heads for a marketing brochure. Nobody's sold on E85 or it's availability on a large scale. I get that. But selling flex fuel vehicles in their current state only hurts the case for E85. People see it as "expensive, poor efficiency, and not generally worth the environmental improvement", when ALL THREE of those factors would be vastly improved when designed around that fuel from the get go. So nobody should think that it's just as easy as changing from one fuel to the next and making small adjustments in timing. That's called "making due" with what you have. It's not the ideal solution. The B16A isn't timing limited and the JDM motor I had in my personal car ran damn well on 87 octane when with it's stock JDM tune I really should have been putting 91 in, but I was too cheap to do so. If honda can design engines that make 120+ hp per liter and not run into timing limitation, I think we should be able to get darn close to 100+ with our motors. Just learn from Honda, the devil is in the details.

Well that's certainly an aspect to talk about, and will lead us getting into cam dynamics. But you also touched on an aspect that my posts should lead one to think about. Let me explain. You you yourself (killerbjt, just so we're clear everyone) just mentioned dynamics of timing effecting BMEP, which of course will be a factor of air/fuel charge heat, which will directly effect detonation. Then you throw camshaft dynamics and that throws a whole different wrench into the machine. But let's talk about that in the real world for just a second. It's been recommend by quite a few people on this very forum, that if you're going to run a high compression setup, especially one like the MN47 with flat tops, that you should be running a more aggressive cam to actually HELP with running pump gas.We could make this very complicated, but I really don't think it needs to be. Let's start at what the more aggressive cam will do. 1. Let's start with torque range shift. This is the most basic aspect that nearly anyone who's ever bought a cam should understand. They're even rated in RPM ranges usually. More aggressive duration cams are generally designed for higher RPM usage. By simple logic if you want MORE power at 6,500-7,500, then you're probably going to lose some torque off the line. 2. With the added duration and overlap you'll have different dynamic compression effects, which is basically a fancy aspect of what I said in #1 just now. Basically cylinder filling becomes less complete at lower RPM leading to lower BMEP, while it will have a benefit at higher RPM leading to higher BMEP. So what did we really just do? I made our peak HP ideal timing much more attainable. We've lowered how much air and fuel we're trying to control at the lower RPMs were detonation can happen easily, and we've moved where we want the most aggressive timing/power output to a range that detonation is relatively less likely to happen. Again though, it's hard to explain to people that haven't had experience with it, but I HIGHLY recommend experimenting with any form of alcohol as an exclusive fuel. Not methanol on top of gasoline, but straight meth or E85. With these fuels you can be running as high as 200hp per liter and never find detonation at peak torque points bellow 3500RPM (in my experience). It's actually quite amazing. Throw enough fuel in and you can play with timing so far that you'll drop off in power because your peak moment of energy is too early, yet there's no detonation. Once you see where the limit is, you start to see the real requirements of the engine very differently. You'll also stop fretting about getting every last ounce of power from a place the engine never lives at WOT. In short, with my albeit limited experience, if I was experiencing detonation close enough to peak HP that I saw detonation during a drag racing row through the gears then I'd be looking for a PROBLEM. I'd assume either there's something terribly WRONG with my tune, maybe an inconsistent sensor. Maybe I had a hot cylinder. Maybe I've got a cylinder that's not filling nearly close to the others. Maybe I'm not running a close enough deck distance to my quench pads. Or maybe I'm just plain running the wrong fuel for my given engine setup. Now, if I was 100%, or heck, even 80% happy with my engine setup, tune, and power and I experienced detonation outside of peak HP + or - 1,500RPM then I'd just tune it out. If I felt it was strangely out of character I'd start looking for the source of excess heat. Maybe I've got some heat soak issues in my engine bay. Who knows. But it'd have to be a strange onset of detonation for me to be concerned. And like Tony said. These are things to learn on stock bottom ends at lower power levels. You don't just build a forged bottom end and shoot for the moon. Start small, work your way up. You'll learn where you need timing and where you don't where it's safe. You'll learn what to expect each time you add 2psi of boost and you'll learn how to watch your intake temps and tune for them. By the time you've got the hang of it hopefully you won't break too many bottom ends on your way to your end goal. I know for my dream build I want to shoot for 400-450 rwhp which I personally think is a bit conservative and should last a good long while. I also plan to do it with as many stock parts as possible regarding the bottom end and head. I also think I'll have very mild looking timing curves because hopefully I'll have done my work right and have a head that doesn't require a ton of timing.... Oh, and I almost forgot. This article is worth the read and I feel pertains to this thread, though indirectly to the author's subject. http://www.davidandjemma.com/mazda/FAQ/quench.htm Also, killerbjt, hopefully you saw what I was doing and didn't mean to say you were wrong in any way. Just that the end point of what you said still correlates to the points I've been trying to get to people that I think have the willingness to listen.

I'm always glad to see more data to support my serious unimpressed opinion of the P90 > P79 debate, especially as it applies to turbo application. I've been telling people for years just to turbo the extremely affordable flat top + P79 combo that can be found nearly for free everywhere, but yet people seem to want to hold on to some stigma that the L28ET longblock is just that much "better".... Thank you for your efforts and the data.

Lazeum ~ (not quoting since Leon already did on this page) The reason the line should be vertical instead of horizontal is because detonation in and of itself, has nothing to do with torque output, or even timing in all reality. But you can't say there's a given torque limit for detonation for any given setup, or at any specific map point. And also, we don't adjust torque output on an EFI map, so it doesn't even make much sense from a tuning standpoint. What we do adjust, that can bring on detonation, is timing. The more aggressive the timing the more likely detonation will occur. You can have a motor that produces 60 ft-lbs of torque per liter (which is very low, run some numbers), and cause it to detonate, even on premium gasoline. You can then modify that same motor to get over 75 ft-lbs of torque per liter (more significant change than it might sound, again, run some numbers), and the motor can still be made to detonate, and will probably happen at similar timing points. Though not identical points they'll have a much closer relation than the torque and power output of said engine. The confusing thing about arguing about this trivial point (and it IS trivial) is that both torque and timing cause heat, heat causes detonation. I think much more importantly than arguing about graph semantics is bringing to the table the fact that many engines can be brought to a condition in which at peak HP RPM ranges that have a detonation limit beyond max power timing. For example: Take an engine in which detonation won't hurt it. Let's say a 250HP SBC. This I feel is a good example because there's thousands of similar motors out there, some even in Z cars. This motor doesn't need to worry about mild or even some moderate detonation, as it simply won't blow parts up. This isn't because detonation forces are a product of torque, but the reality of the fact that the more power you're making for a given displacement has a proportionate amount of air and fuel and you'll see similar increases in forces exerted to the internals, thus detonation causes more damage the high you go in power per liter. Poing being, this lowly 250HP motor can detonate mildly all day long and not care much at all. Now, as anyone who's driven an old 60's pickup can tell you, detonation will most likely happen at lower RPM. In fact, it's not too uncommon to be driving said truck, start going up hill and hear the engine start to ping, so you downshift and tada noise gone. This isn't because the timing curve for said engine is a bad curve. It's more to blame for the fact that like the burning of fuel, detonation needs time in order for it to happen. Forumla 1 engines don't fret themselves with something as trivial as detonation because they literally out run it. Thus you should see that detonation is much more time specific than power specific. I've even experienced this phenomena in the honda world. There's a big shift just in moving peak power from 7,000 to 9,000. All of the sudden not only do you find that you're running more timing, but you find that you can keep a heck of a lot more of it as you tune down from your race gas. In fact, one engine that I helped a friend out with we didn't lose ANY timing at peak HP going from 110 octane to 91. I attribute this merely to the fact that the higher you get in RPM, the less detonation becomes a concern. Now, obviously detonation breaks a lot of motors, so it's definitely a concern for most of us. I'm just bringing to the table that often it's because of aggressive tuning UNDER THE CURVE that's the issue. It might sound backwards to some tuners, but it's a reason that when finding the limits of timing I start from the top down, not bottom up. I also believe your tune needs to be fairly stable before reaching for limits, but I think when really trying to find those limits you're safer doing it at peak RPM than you are the very bottom off idle.

Yes, if cost is a concern, the L28ET starts to look really good. No fabrication required. Saves a lot of time, energy, and overall hassle. Even if you have a welder handy, any swap starts to have added cost when it's a motor that never came in that chassis. Now, I've never felt that should be a huge reason to stop someone from doing a swap, but it certainly should be a factor in ANY budget.

Ah again!!! So true! I didn't think about it but detonation is more a product of the pressure fluctuation of timing, not torque, therefore it SHOULD be a vertical line. I still think it should start as a soft red, not hard, then work into a deep red.

Well I can tell you he still drives the car, and uses it to DD quite often. Beyond that, I'm not exactly sure. My speculation tells me he got sick and tired of the people here telling him what he can and can't do when he's the one out there doing it. He used to be a regular poster on the forums, now I rarely see him at all. So either he got tired of hybridz, or his life is significantly more busy that he was before and doesn't feel he has the time to share with us. ...well, that's my speculation at least.

Ah, you're right. I'm sorry. That said, you never lean out a fuel mixture to fix a detonation issue. Bad juju!

Well then consider 500rwhp the foreseeable limit until you guys prove otherwise! Lazeum ~ For one, the detonation threshold should read reverse color. You get softly into detonation, often without knowing it, until it becomes more aggressive and becomes obvious. The other issue I have with that chart and what you said is that it assumes max potential achievable torque doesn't move. It DOES move!!! That's what I'm saying about comparing different fuels. They all have their own independent chart curve with different limits. And there's a heck of a lot you can do to raise the detonation threshold without changing your fuels. Detonation has to do with HEAT. I've seen guys who once they traced their root cause of detonation found that their fuel was getting super-heated because there was so much unused fuel being pumped through their lines that the fuel in the tank would slowly rise in temperature. They added a fuel cooler past the pressure regulator and the problem was solved..... That's what I mean when I say this isn't as easy as "run less timing" of a subject. It's extremely complex and requires looking at the WHOLE PACKAGE.