Gollum

He's right. Sticking with the L series in the long run can be very counter productive from a financial and practicality standpoint. But they sure can be fun motors. I was also going to mention, that the L24 and L26 have around a 1.8 rod/stroke ratio, which isn't bad. And you can still bore a bit over what the L26 is at. The NA guys get away with running a 3.1 or 3.2 liter setup, but under high HP boost application they tend to fail at the bore level, most likely due to warping out of round.

Group buy rota's w/ good tires. Probably the best mod you'll actually DO for under $1.5k. Good wheels and tires will help pretty much every area of performance. But as it's been stated, search, read, search and then read some more. It WILL save you money, though it WILL take a bit of time to read and absorb what you need to. Instead of working on power, take your small budget and work on things that improve MORE than just straight line acceleration. Work on removing weight, improving brakes, making the car simpler. Also invest into yourself with some track time, even if it's at your local autox. Improving yourself is cheaper and easier than the car.

Woops, sorry there bob, I was thinking we were talking about HP/Liter, guess that's what I get for posting too briskly. He's making a bit shy of 100 fl/L, but his numbers certainly are impressive. Over 300hp on one dyno by 8400!!! And he IS running pump gas, on 13.4:1 compression!!!! Makes me wonder how much he might have on the table if he were to put some race gas in. If you look through that link though, he certainly knows his stuff when it comes to honda heads. His attention to detail is definitely up there and certainly shows that there's no "magic bullet" but that it takes a painstaking level of detail to everything to put those kind of numbers down. Overall, the fact he's making 150hp per liter by 8500rpm on pump gas is just astounding.

Doesn't sound impossible... Unless he's running pump gas petrol on that dyno run... Then that's a little crazy. The type R B series head has the capability to rev well into the 10k range and beyond. The key is to get it to breathe up there and then package the rest of it to match. Even right out of the box the type R keeps pull hard all the way to it's rev limit, and onces lifted doesn't start dropping in power until about 10,250, then I think you're reaching the limits of the stock valvetrain. (this is first hand experience btw, so don't ask for "magical internet references). I don't have any hard numbers for what I've seen on that engine configuration, but I can say that as far as RPM's go, those motors are wild.

Didn't anyone ever tell you that you weren't supposed to do that? In all seriousness though, get well soon. Don't over work yourself. Enjoy the down time with some good reading.

That user showed up to my last meet tony. What a work of art! (510six)

@madkaw ~ Find a car that hasn't spent full summers sitting in the sun! The only leak I've seen consistent with SEVERAL of them is the corner panel leakage, and the door leakage. The doors are an easy fix. The corner window seals are a bit more of a pita, but use just a seal compound, no rubber there. All of mine didn't have ANY leaks in the hatch seal.

But as far as I'm aware, the NV tests aren't nearly as stringent. And we here on this site are usually here because we LIKE our cars, but I know what you mean, I do get a thumbs up from time to time. This is all a very good summation to what I believe as well. Like I said though, the main thing that kills it for me is local laws, nothing else. I know that even in the more strict areas of Europe they require a very detailed spec inspection to make sure the car is running clean and is safe for road use. And I completely agree with most of their setups. Here in CA though you can get failed just for changing out a fuel rail, which makes NO impact on the tune, air fuel ratio, or carbon foot print of the vehicle. Our laws are completely out of proportion.

Tony, our gas here in CA sux big huge spaceballs! From looking at dynos, and looking at tune files for various setups across the USA, you can SEE that people aren't getting as much power and timing from our 91 octane than other people get from 91 octane in other states.

It depends on what you're looking for. Do you want a track engine that runs on race gas, or do you want a reliable street engine that will go 100k without even blinking? I never said the MN with dish pistons wasn't reliable, I just said that some people might consider it just that. The MN47 is BEST suited to race applications with HIGH compression. As people have already touched on, you're rebuilding this engine for a reason, and finding that reason is kind of paramount, don't you think? As it's been said, the L engine is VERY prone to detonation. IF you want a race engine and run race gas then run as high as you want! Anything is possible. But just slapping together a combo and saying "well it's in the 9's it'll be fine" is just being ignorant. Yes, there ARE street driven L engines over 10:1, and they're mostly built by very experienced builders that understand the short comings of the L engine and know them pretty well. What I was getting at, is that if you just want to throw together a street engine, pushing conservative numbers, then you're better off with one of the more common combos. And also, quench REALLY DOES make a big difference, and you're sacrificing nearly all of it with your setup. A P90 with flat tops is less detonation prone than a P90 with dish pistons. We've seen this with turbo L series, that the P90 with flat tops can make quite a bit more power with less timing. Sure, it detonates easier timing for timing, but it'll make more power overall. This isn't because of the compression really. It's that the engine doesn't NEED as much timing to make a good complete burn. There's a big difference between your timing detonation limit, and your timing power goal. Some engines, like the EVO, don't make much extra power with extra timing. Putting flat tops on the P90, or even the MN47 makes the engine need LESS timing for power potential, but as BRAAP was getting to is that on pump gas you still can't always reach the timing power potential of this combo (flat tops with the MN47). But you CAN reach the timing potential of the P90 with flat tops, and N42/47 with dish pistons, on pump gas. So again, it all just depends on your goals, which I haven't seen stated here in this thread.

At most junkyards you'll pay over $150 for the ECU and all the little tidbits you'll want, maybe more at some actually. The fully built MS board can be had for not much more. The REAL cost is in the OTHER things you'll need ANYWAYS in either situation, like a wideband, laptop to tune with, etc.

Ummm... I wasn't starting a flame war, but as Bob is getting to, you're not making sense. And that's my point... Either you're not communicating what you're REALLY trying to, or you simply don't understand the subject matter. I'm assuming it's the former. Because I'm sure you're aware you could put nearly ANY motor in the M3 and it'd be a great track car. The engine does add a lot of character to the car, but the bore/stroke and stroke/rod are only a sliver portion of what makes the character of the car.

My first car that I called MINE was a 280ZX, purchased about a whopping 6 months or so after joining this site, not much longer than getting my license. I bought it just before our wonderful state of california changed the rolling smog year law, meaning that my 80 280ZX would never see smog test exemption... I've now owned 4 of these wonderful cars and more than ever really wish I didn't always have to worry about those pesky bi-annual inspections. Now owning a S30 as well, I've really learned what I love and hate about the S130 cars, and would like to share with the rest of you my feelings, findings, and overall fantasy of all the S130 is and could be. I think something that we have to remember, as I move on here, is context. These cars are cheap. I mean I paid $2k for my first one, and I grossly overpaid for it. I bought my next for $500, and had it running in one weekend and drove it over a year with no issues. I bought one after that, a turbo, for under $1,500 and then got my most recent one for FREE, and drove it home even! So if it seems like I make them out to be the most amazing thing since sliced bread, then just remember the context, the fact that they're dirt cheap. First I'd like to talk about rust. So many cars are plagued with rust issues, and I have to say that besides some key areas these cars are pretty good. The biggest issue is that the corner panel windows leak. I've only come across a handful that didn't, so rest assured they pretty much all have this issue. So during the winter, rain leaks through these seals, and then water sits in the corner panel, on both sides of the trunk. The driver's side (left hand drive) doesn't seem to rust through very easily, I think due to a coating they used or something. The passenger side though, it all gathers in the spare wheel well, and it rusts through fairly easy. In fact most S130s I've seen need all new spare wheel wells because they're rusted so bad. But overall the rest of the car is pretty solidly engineered. There aren't any water traps that I've found that are guaranteed rust areas. Be careful of the gap between the door and window though, as these seals tend to wear over time, or even get torn off. This will allow a lot of water to sit, and even fill, the door. As a temporary solution you can remove the plugs on the bottom of the door so the water drains, but this is just a temporary solution. Weight, weight, weight, weight. These cars are often talked about like they're ridiculously heavy, and that it's a fact you can't fix. I'd like to stand firm on this topic, and enforce the fact that they are NOT a heavy... CHASSIS. They CAN be a heavy car, but I've seen it completely depend on how they're equipped. A fully trimmed, as though off the showroom floor, with a full tank of gas, NO optioned 79' 280ZX will hit the scale at around 2500 pounds. The bumpers I'd swear are even heavier than the bumpers of the 280Z, but I've never actually compared them side by side. These cars don't look nearly as awesome bumperless though, as the rest of the body was well molded around the bumper, meaning that removing it makes it look like it's lost a tooth or something. But having cut these cars up now, and having seen where all the weight lies, I can firmly say that they're JUST as light, if not LIGHTER of a chassis than the S30. This means that all the difference is removable, or fixable. Other than the obvious bumpers, another big area of easy savings is the hood. That thing is a huge beast of metal. The rear hatch is really heavy too, but most of it is the glass, not the metal. If you have a wiper back there, removing it will only save about 15 pounds at best, but it's an easy removal. The doors are also pretty heavy, so if you have a full cage with good side protection you might want to look into gutting the door a bit. The nest heaviest part of the car is the rear suspension. If you dropped the entire rear subframe assembly I'd bet it weighs in at over 150 pounds. Now, a lot of that is the R200, iron calipers, rotors, etc but the lower control arms are seriously heavy. If someone were making quality tig welded tubular control arms they'd be worth every penny. Handling, with these are, well, interesting. I find that even on a stock suspension 280ZX my cornering speeds aren't bad. They handle really well up to the limit but the problem is that most people can't find the limit very easily. They tend to be really dramatic before you get there, and you keep pushing, and keep pushing then BAM, the back end is sliding out nearly impossible to control. Now, once you learn where it is, you CAN control it and it's not that bad. But these cars don't like rough inputs, as it makes it that much harder to predict. If you go over the grip edge smoothly, and give it smooth inputs for correction it responds very smoothly. I think these cars CAN be fast, but where this car's doom lies, is in the fact that it doesn't FEEL snappy. I can understand the argument people have, as a sports car SHOULD feel snappy, and I think these cars can. It just takes a bit more work than in a S30, or even the Z31. One of the big things is to ditch the steering system if you don't have a rack and pinion setup. This will require a crossmember swap, but that's not TOO big of a deal really. The manual steering models were all rack and pinion if you want to go that route, and the 82-83 power steering models were rack and pinion. The power from the NA models are a bit weak, but for their day weren't all that bad. I'd even say they're plenty fast for most young drivers. They have enough HP to get you into trouble easily enough if they're in good shape. If you think about it, with just some minor work and some moderate weight reduction you could make them a 14 second car. The real beauty is that you could grab a 82 turbo car and just getting it in good running shape it should be an easy low 14 second car, and we all know that these engines can easily reach 300hp without breaking a sweat. But what I'd really like to get to now, is the benefits that are often overlooked. There's plenty of bad that I've touched on, but there's some good that's often never talked about. One is the fact that you can fit HUGE tires without flares. This means you don't have to spend tons of time rolling fenders, or attaching flares and grinding body panels away. Just but the group buy rims and buy tires. 245 easily fits all around, and that's plenty of tire for most street cars. 275 wide even fits with some careful work, still much easier than fitting even a 255 in a S30 imo. Another often overlooked aspect is aero. Now, it's still not like a new car at all, but it fixed many of a huge issues with the S30, and is hideous for it. Nissan I think did a good job fixing the looks side with the Z31, but in reality what they made was a primadonna Z that fit into the styling of the era. The S130 though at least retains part of the looks, while laying the foundation for improved aero. With some attention to detail of the front end, small work on the roof and hatch area you could have plenty of downforce for a street car, and low enough drag to not be a huge hindrance on the mpg. Like the S30 though, the devil is in the details. There's lots of little things that still need work for anyone looking for every ounce of slippery wind potential. And the biggest downside for most people I've just hit on, the looks. I agree the S130 isn't exactly a "pretty" car. I can say that it's not as bad as some other 80's cars, but it's certainly not them gem. And in all honesty if you can't LIKE your car, then why do you have it? And a lot of people LIKE a car based upon how it makes them FEEL when the LOOK at it. This means that the LOOKS play a huge role on how it's accepted by people and/or it's owner. In the end the 280ZX is a conflicted car that's trying desperately to hold onto the look and feel of the 60's and 70's GT cars, but still be "new" and "exciting" and it just clashes in many ways. If you like it, more power to you. But I for one have gotten to the point that when I look at the 280ZX the FEELING I get doesn't come from the looks, and I see past the looks. I see the character of the car beneath the skin, and I can appreciate the unexpected sleeper factor. People don't expect a S130 to be packing much heat, and I kind of like that. But, the sad fact, and much of why I'm writing this, is that I plan to sell my last and only S130 down the road here (most likely later this year). Why? Because I live in california. It's that simple. The limitations put on me by the state I'm in makes it simply too restrictive, not letting me build the car I'd want to. Now, I know that much of what I do with my S30 isn't "legal" but I do keep believe in keeping my cars running well, which is what the smog checks are supposed to be about. But not having to deal with those inspections makes all the difference. And I'm sure there are people that read into that and would want to change the laws to force my old S30 off the road. And if that day comes, I'll just move to custom vehicles registered with SB100's, or I'll leave the state. And it's not that I want to go all that radical with a S130. I actually just want either a hot L28 with ITB's, or a RB engine with ITB's. Either would give me enough power for a fun street car and provide the response and sound to really "awaken" the character of the car. Even just a stock RB25DET would be awesome, but not smog legal in CA. You can legalize a 2JZ swap though... In the end, I'd rather have old cars as project cars that I can feel free to work on without big brother looking over my car. The ideal post smog test car that I'd actually buy, is a subaru. But that's only because they don't have 4WD smog dynos.... yet... so you only have to pass visual and the older sniff test. Much easier to pass. Also, being turbocharged you can obtain your power that way, which won't show up so readily when smogging, and is reversible in just a moment. Anyways, I love the S130, and hope to own one as a project someday. Sadly I'm not sure that day will ever come. But here's hoping.

John already hit the nail on the head. Get all the "little things" (like, umm... started) done first, then move onto power mods. Save up for megasquirt. It's NOT that complicated. It's simpler than a head swap imo, and could be tackled quickly if you're prepped for it. MS will probably help you pick up at least 10% more peak power, probably a good 15% extra power in the lower range, and make the car MORE drivable and get BETTER gas mileage. It's probably the single most important thing you'll replace on the L engine. That stock EFI is the pits.

Define "a lot of work", as you're rebuilding your motor. Seems like you're already past what most car guys consider "a lot of work". It just take a fuel system that won't be corroded by the alcohol content (new hard lines possibly, new soft lines definitely). Then you just need carbs and jets that are alcohol safe and capable of running the 30% extra fuel you'll need compared to the same petrol setup. Might also be wise to swap out the stock tank for a fuel cell, something any race should be doing anyways though. And also define "dependably". Your current setup with dish pistons and MN47 could hardly be considered "dependable" on certain, other forums. But I do agree with the large consensus here, that if you're going to run this as a street engine (NOT a race engine) and just want to run 91 octane on a stock, crappy distributor then take the MN47 and put it to the side, or sell it. Put a N42/47 on and call it a day. Or swap out for some flat tops and put on a P90/79. But E85 does offer the ability to get "the best of both worlds" so to speak. There's guys (not L engines) that have run 13:1 comp with boost pushing over 200hp per liter. I would call that "timing limited". In NA application there's guys (again, not L engines) running up over 15:1 on E85 that costs less than $3 a gallon pretty much anywhere in the country and as low as $2 a gallon in some places. That's some cheap race gas. Even with the MN47 and flat tops, you could run two different timings for petrol and E85. Having carbs would make the swap a pita, but IF you were staying EFI and running megasquirt which was also controlling spark with just a simple map flash you could switch to petrol for casual cruises and road trips, where the loss in power from the retarded timing wouldn't be a big deal. I'm actually wanting to get some documentation together and write up a thread talking about the benefits of E85, as I think it's the best bang for the buck mod most people could do, and it's costs are sometimes less than what many spend on meth kits.

Forget all the compression and timing arguments. Just run the MN47 with flat tops, then put E85 in the tank. Done!!! I've seen E85 allow guys to see where optimum timing actually lies at the TOP of the power band, mean that they gave it more timing and there was no knock AND less power!!! Whoa! You of course need to run a lot more fuel than 87-93 octane petrol, and you have to run it rich when feeling the waters of timing, but once you get it dialed in it makes TONS of power EVERYWHERE. And I'd be a lot less scared of knock on a 11:1 L series on E85 than a 9.5:1 L series on california 91. I personally want to run a mildly shaved P90 with flat tops with the "A" cam, turbocharged non-intercooled w/E85 targeting around 350 whp. That'll blow some minds, ya think?

The mid 60's falcons and rancheros are indeed quite quintessentially the "bomb diggity". All the same weight and handling potential as the early mustangs, which "isn't bad" when done right. The share lots of common Ford bits and are much more socially bendable compared to the pony car. A '64 falcon can show up just about anywhere and be cool, and to some level respected by all. Putting a L engine in one would be just the right "twist" to common methodology in my very humble but honest opinion.

You can have a 2.5 liter STI that's not peaky at all, but IS rev happy, and doesn't bog at launch unless you don't know how to launch AWD turbo cars. You can also have a 4.7 liter long stroke Tundra that would "bog at launch". I don't mean to come across as an a-hole, but either you're not well versed enough to explain yourself (which is fine, I'm right there too in a thread me and Tony D have been going back and forth on), or you simply don't know what you're talking about. So much of what you said in that post is car setup specific, and has nothing to do with the bore/stroke ratio or even stroke/rod ratio of the engine in question. From what you've said, what I THINK you actually want is a motor producing at least 100HP per liter, and put into a car in which you have at least a 9lb:HP ratio. This is quite easy in a Z car, but if you insist in a peaky motor, then you're going to want a NA engine making over 100hp per liter. This means you'll either want a DOHC 4 cylinder, 6 cylinder, or even a highly modded L series would fit the bill just fine. I don't say V8 because at over 100hp per liter, and peaky it'll be a beast, and insanely more expensive to build, and most likely way over your power goals. And I say this all in good fun, but I kinda laugh when I hear people say that they like peaky motors... That's exactly opposite of what any veteran race drive would say, and also exactly opposite of what any professional tune shop would say... And there's a very good reason for it. It's not fast! Simple as that. A 240HP S2000 produces LESS NET HP than a 225hp pushrod 5.0 ford, meaning put in front of the same transmission in the same car the 225hp engine would be FASTER!!!!

I was just reading through this thread for the first time, and when you mentioned not having the head temp sensor hooked up I, quite seriously, smacked my forehead. Glad you got it all worked out though. In my experience I can't even get an L engine to RUN at ALL without that sensor, well... I can but it's barely drivable. You'd be amazed how little weight distribution actually matters in the long run. What matters is how well your chassis and suspension is tuned for the balance you have There's plenty of examples of cars with WAY off balance weight that are kings of handling.

It's not bad really, I'd just drive it like it until you have the time and money for a good chassis. You can find pretty much rust free S130 cars here in CA for less than $1500 RUNNING, on a regular basis. The S130 was much more rust resistant than the S30, and here in CA as long as it didn't spend winters parked in mud they usually hold up pretty well. Might just be worthwhile to start with a better chassis, rather than pouring money into fixing problems on your current chassis. But like I said, just drive it. Enjoy it. Don't let a little bit of rust freak you out and make you drop the car as a project. Just don't pour money into things that can't later be removed and put onto another chassis.

I don't have MS, but I've read through the threads on it more than just a few times. That kit is the entire ECU, but that's probably not all that you'll want to have on hand when you do the swap. The big other key item would be a wideband of some sort, like the LC1 and compatible controller. Without a wideband you'll have no reliable way to tune the ECU. You could probably load a map from someone with a similar setup, but you'd want to get to a dyno ASAP, and if you make ANY changes you'd be heading back to a dyno. I've talked to several professional grade shops that don't care about dyno tuning for street cars and consider it "an unneeded luxury" or "something to make the customer's happy". This is because with a good wideband you'll get a better tune on the street, and be able to compensate for a wider range of factors that simply don't happen on a dyno. Dyno tuning is for you to use if you don't want to learn how to tune the car yourself, but if that's the case then there's better options than megasquirt. MS is truly for the person that WANTS to tune their car themselves. All that to say "you'll want a wideband". The MS FAQ/Sticky covers how to use the factory distributor, which is fine if you're not pushing the limits of the stock internals. But if you're going to reach those 400+ numbers, then you'll probably want to run a 36-1 timing wheel on the crank triggering coil packs. This will give you much more accurate timing, and a much wider range of control too. And personally, I think if you have ethanol near where you live I'd just run ethanol instead of meth. E85 with an intercooler has no need for extra cooling imo. The nice thing about running E85 is that you don't run into some issues that you might have when spraying meth aside from gasoline. If you have a meth tank and for any reason you run out, or you get a clog in the system, or if your pump fails or just drops a bit of pressure then you run the risk of blowing your motor. Where as if you're running E85 you'll immediately notice most fuel supply issues. You also have less parts possible to fail in this setup. The other upside is that you can tune with it, and without it, and switch back and forth if you need to (just make sure there's less than a gallon of fuel left in the tank first!). This would also be more soft effective than meth, as you're not buying as many parts to get it up and running, and E85 is much cheaper per gallon than meth, and gasoline too! In a rough tuned 350+whp STI running E85, the cost is effectively THE SAME per mile when compared to CA 91 octane premium. The reduction in MPG is roughly 20% (not even tried to tune for economy) and the cost is about 20-25% less. So it's a wash here in CA. I'd imagine that in texas you might even be saving money over premium. Something to look into.

Do you know how hard it is to find examples of systems like these Tony? I'm sure I'll figure it out, but I haven't quite figured out the best way to control this for street use, that'll be reliable and easy to tune. I tried mocking up a table with turbo speed on one axis and engine speed on the other with the variable being percentage of the BOV opening... I realized after staring at my computer screen for about an hour that it's impossible to tune this without first setting a boost curve, because otherwise I can't calculate what CFM the engine will be using. Anyhoo, I've got a mock engine idea I'm making some tables for, we'll see where I get with it. Maybe one of these days I'll actually build me a megasquirt system, then I can play around coding something up.

As said, there really isn't such a thing as "perfect compressor" that would fit those three engines, despite their similar HP goals, and thus similar CFM/Min of air and fuel requirements to meet that HP goal. listed first is the 5.0, then 4.6 and then the 1.6. Vol. Eff. is based on dyno software emulating true factory torque curves. Should be close enough for theory's sake. http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.66&pr3=2.26&pr4=2.26&pr5=2.26&pr6=2.26&pr7=2.26&airflow0=4.5&airflow1=7.3&airflow2=14.5&airflow3=24&airflow4=34.2&airflow5=44&airflow6=47.8&airflow7=49.3&product_id=109 http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.41&pr3=1.75&pr4=1.75&pr5=1.75&pr6=1.75&pr7=1.75&airflow0=3.8&airflow1=6.1&airflow2=10.8&airflow3=17&airflow4=28.2&airflow5=40&airflow6=42.1&airflow7=42.7&product_id=109 http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.86&pr3=2.66&pr4=2.66&pr5=2.66&pr6=2.66&pr7=2.66&airflow0=1.5&airflow1=5.6&airflow2=13.8&airflow3=26&airflow4=32&airflow5=37.6&airflow6=37.9&airflow7=37.8&product_id=109 Compressor surge might be an issue still for the 1.6 there, but it's in the decent range for the V8's. Though it's amazing how two V8's of similar displacement, with stock power levels being semi-close can read so differently on a map. The turbo used is the GT3076R. One of the larger compressor's for the GT30 turbine frame, not sure how it compares to a T3/T4 typical hybrid. If we were seeking IDEAL turbos I might choose something more like this: The 5.0 would get a GT3782R, leaving some room to shoot for 500hp and in a good efficiency area for street use http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.66&pr3=2.26&pr4=2.26&pr5=2.26&pr6=2.26&pr7=2.26&airflow0=4.5&airflow1=7.3&airflow2=14.5&airflow3=24&airflow4=34.2&airflow5=44&airflow6=47.8&airflow7=49.3&product_id=44 The 4.6 would get a GT4294R letting it get into a really nice range for upper RPM use when you stretch out the motor and use those rev's it's got. Might be sacrificing some street performance but giving good race use and quite a bit of flow left on the table if more HP was desired. http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.41&pr3=1.75&pr4=1.75&pr5=1.75&pr6=1.75&pr7=1.75&airflow0=3.8&airflow1=6.1&airflow2=10.8&airflow3=17&airflow4=28.2&airflow5=40&airflow6=42.1&airflow7=42.7&product_id=49 The 1.6 would get a GT3571 http://www.squirrelpf.com/turbocalc/graph.php?version=4&pr0=1&pr1=1.07&pr2=1.86&pr3=2.66&pr4=2.66&pr5=2.66&pr6=2.66&pr7=2.66&airflow0=1.5&airflow1=5.6&airflow2=13.8&airflow3=26&airflow4=32&airflow5=37.6&airflow6=37.9&airflow7=37.8&product_id=41 This is probably the most interesting of the choices. It's "within" use of this application, but it's hard to find a turbo for this application that doesn't say "danger danger" all over it, because you need the larger compressor to have enough air flow for the HP goals, but it's low displacement makes it easy to put into surge... So you end up doing what big phil did basically, go with a larger AR on the hot side, or a larger hot side all together. So this GT3571 has a huge turbine/hot side frame, and a smaller compressor than the other engines. But this prevents borderline surge constantly, and puts you in a decent efficiency range for street driving, but racing on this engine a lot might lead to early turbo failure... Hmmm... wonder why those turbo honda guys seem to blow up turbos a lot when they're pushing 500hp.... hmm....

Just because you say you're busy (which I believe) I won't ask any more questions for now, since I think I'm starting to get it. Again, everything you've said I've TOLD and tried to TEACH to others, to explain why PSI is poorly understood among people, and how little it really matters, but again, my language just isn't there to communicate it obviously. Here, I'll edit my last post to better reflect what I was getting at, which you in turn answered well enough for me. I think the irony in the three engines I gave examples of, is that though they'd all require very different setups, they could all in theory use around the same compressor, since the flow requirements are the same in the end. The exception would be that the Honda 1.6 liter will end up in a very different part of the map due to it's higher pressure ratio required in order to reach 400hp. If finding a compressor to meet the needs of all these engines, you'd probably end up with a compressor that's never really perfect for any of the engines. I'll calculate some load maps and see what I come up with, for theory sake.

I'm pretty sure I understood all that, so I'm wondering if I'm just not phrasing things correctly. I realize that pressure ratio/psi AND flow will be direct variables depending upon engine displacement, volumetric efficiency and power goals. If you have a large efficient engine it won't need as much PSI as a smaller less efficient engine to reach the same power. IE: Even a POOR efficiency ford 5.0 stock only needs a quarter the PSI to reach 400hp as a high efficiency honda 1.6 liter. But by the same token the 4.6 ford DOHC needs LESS PSI than the 5.0 to reach the same power, due to being a more efficient engine. Three engines, same power, very different pressure ratios/PSI requirements. I guess my point is that it seems as though YOUR point is that this system allows you to run a much larger compressor/smaller turbine (much more offset than the typical T3/T4). And I'm saying that by what I'm seeing on load calculations that you'll be well into surge territory under normal wastegate control (duh, I think we've covered that, thanks for your patience with me ). So in this system you dump the excess air the compressor is making at lower RPM (or any for that matter) to get it back into stable region of the map, but what I'm asking is "won't that be a low efficiency area of the map?" and "would you want to vent MORE air to create MORE flow through the compressor to FORCE it into the better region of the map?" I think that make sense. And honestly, based on the dyno in that other thread, I think by ramping up the boost gradually like they (electromotive) did, they're staying in a good area of the map anyways. They're obviously not shooting for JUST past the surge point at 4,000RPM. Though we don't have a compressor map for the turbo they used, so it's hard to guess that kind of stuff. PS On a side note I was looking through pictures of the F1 turbo systems back from the 80's and I saw on several of them obvious speed sensor devices. What I didn't expect was the pre-turbo throttle bodies. From some reading it looks like they were used in tandem with a regular throttle body usually to keep idle speed of the turbo higher. Interesting alternative to the modern conventional BOV.