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Gollum last won the day on October 11 2013

Gollum had the most liked content!

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About Gollum

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    Tree Killer
  • Birthday 07/07/1987

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    Vacaville, CA
  • Interests
    Cars, Computers, Guitars, anything that makes music, or goes fast, or goes fast while making music!

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  1. Gollum

    180 Degree L28ET Intake

    I blame 510six for starting me down a rabbit hole of research about 7 years ago. He was also running dual fuel staged injection with E85 on the secondaries and pump gas on the primaries. He also was running no intercooler. He also put 400 to the wheels... ...off the bottle... ...What shocked me most was how LITTLE E85 he'd burn through. He had a small 3 or 5 gallon tank that he wasn't really ever worried about disappearing without just cause. Could have a lot of fun with minimal impact on the "fun tank". The point in my mind isn't just avoiding an intercooler, that's a byproduct. The goal is high mpg on cheap pump gas, and also being able to use "cheap" race gas (e85) without bothering with the drawbacks of needing to go get the good stuff when you want to have fun. But running e85 in cruise condition on the highway mile after mile isn't necessary in any measurable way. Sure it's more work to dual pump dual tank, dual injector, etc. But the benefits are great in the long run. Though his (510six) sanity shouldn't be what we consider "benchmark", and this is closer to his car's current evolution:
  2. Gollum

    180 Degree L28ET Intake

    It's actually not that hard these days, even in megasquirt: http://www.msextra.com/doc/pdf/html/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.pdf/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5-216.html You even get to adjust the range/curve of the switch method you use: http://www.msextra.com/doc/pdf/html/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.pdf/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5-221.html You can also adjust target boost curve on each table, so if for some reason the switch never happens you can have a sane boost target for whichever map you're on. In flex fuel mode using the E85 sensor this would be handy in case for some reason your ethanol station filled the tanks with regular gasoline (it's happened, and blown up motors): http://www.msextra.com/doc/pdf/html/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.pdf/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5-225.html In short, you tune with pump gas without the switch over. You set a tunable boost curve and spark limit the motor so that it stays safe if boost runs away beyond fuel capability. You then move on to tuning with JUST the secondary fuel (E85 in my case) and get it tuned, with particular attention to where you'll be using it most, under boost. Once that's done the flex fuel sensor will do it's work to blend between the two extremes based upon sensor input. This whole process is done on your E85 injectors. Now, in my case you likely already have a working pump gas tune on another set of injectors. And that's where this comes in: http://www.msextra.com/doc/pdf/html/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.pdf/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5-116.html This allows a injection switch over from one set of tables to a second set of tables, along with precalculated adjustments for injector size differences. Obviously your small injectors might need some trimming to get back to perfect on pump gas, but odds are it'll be darn close, possibly just needing some overall trimming, not detailed cell fixes. That said, in this mode, your essentially using TWO tables (each) for fuel and spark. MS3x supports FOUR tables, which means there's a way to configure that I haven't figured out yet in which in theory you should be able to get all four potential scenarios working (flex sensor on both tanks with a table for each plus staging switch over) As for the oil changing every 1k. I've heard people say that, and I think it's paranoia. I've met people that tune E85 for a primary living, and they suggest typical 3k rotations on street driving, or every race event if you're tracking it regularly, but they recommend that for pump gas too.... I think the harsher reality is that going from pump gas to E85 when tuned properly is AMAZINGLY fun as the car behaves so differently, so you spend a lot more time with your foot in it. And anything driven that hard should have it's oil changed regularly.
  3. Gollum

    180 Degree L28ET Intake

    The largest concern I have is with shutdown. I've seen plenty of people run e85 daily for long periods with little effect on wear. What's more amazing is how clean everything is at teardown. My larger concern is rust on cylinder walls if you don't drive for longer periods (like over the winter, because fair weather car). This is one of the reasons for going dual fuel. Running pump gas off boost before shutdown should allow the cylinder walls to stay coated between running.
  4. Gollum

    180 Degree L28ET Intake

    Well, and to throw a noodle into the bowl of fruit loops, there's a good number of people that are using straight water injection pre-turbo. With a fine enough nozzle and enough volume the aim here is to not change the compressor pressure ratio, but to improve output via basic thermodynamics. Nowhere on a compressor map is it assumed that compressor inlet is a perfect atmospheric barometric pressure. Lower the inlet pressure via temp drop via water, and suddenly you've increased max compressor flow. Great way to cheat a small turbo into flowing more air. Personally, I think it's a neat idea but has limited use cases. If your turbo isn't running off it's map already, then you're just adding another molecule that's robbing space that could be used by oxygen. Though, if I DO end up temperature limited in my build, it might be a viable option...
  5. Gollum

    180 Degree L28ET Intake

    Only thing I'm going to bug you about in this post is that fuel doesn't burn if it doesn't vaporize. If fuel vaporizes it has created temperature drop by rule of physics. This means that we can measure "vaporization" efficiency with a smog dyno Point: The vast majority of fuel gets vaporized, especially in port injection, and with much greater accuracy, hence efi running cleaner (when tuned). I don't think I can over-stress though, that OEM's want to move to DI, and why? If 100% vaporization were harder with DI, I'm not sure they'd be so eager...
  6. Gollum

    180 Degree L28ET Intake

    True, my last post was stabbing towards the "reality factor" not the "how much am I giving up factor". Yes, E85 isn't listed, and not ALL fields can be calculated by mixing numbers, as many things have dynamic effects on the fuels. But some things like the latent heat of vaporization scale very linear in the blend. The evidence of this can be seen in how well certain aspects of flex-fuel tuning work all the way from E10 to E85 and anywhere in between with simple table extrapolation. While we can get stuck in the details of science, real-world tuning application says that most things blend linearly just fine. Well, as discussion basic bowl cleanup, mild unshrouding, and intake port centerline lifting will all be done. I'd be surprised if I'm not flowing over 190cfm on the intake side. But speaking of just dividing numbers, you also didn't note the difference between the number of intake runners when comparing here. But anyway, the main compounder of heat in force induction is PSI, and the restriction of the air pump is directly related. I think we've both proven we understand that 100psi of boost might make 100 hp on some motors, and other motors might make 1,000hp with just 10psi. It's all about flow. That said, The G25 turbos should match stock-to-hot street L28 builds nicely, though I think it's a bit low on flow potential on the turbine side for a real hot L28 trying to chase world records. The compressor on the G25 I think is slightly biased towards higher PSI than I think most would really want to run on a L28 unless you're going to run low compression. This is also evident in the recommended displacement range Garrett advertises of 1.4-3.0 litres. An L28 is knocking on the door of that, but would likely be just fine as it's a mild flowing head. This is a turbo that WANTS to live around 2.5 pressure ratio and will work up to 3.5 in extreme cases. In my use case I'd be living between 2 and 2.5 pressure ratio, and where I land on the efficiency would depend on how well the head is flowing, which would also determine achieved power. Good point, though they're dynoing over 2khp now , so there is that. All true, and I agree and knew all this ahead of time. My point of including it in the discussion from the get-go is that they weren't running an intercooler, and were still running sub 7 second 1/4 miles and added an intercooler NOT because of heat management issues, but heat CONSISTENCY issues" Their goal with the new build was all about keeping times consistent. Carburettors suffer from icing for a few reasons or might be more accurate to say that they have a few things working against them that leads to icing. And it should be noted that icing is an issue in LOW power setups, not just HIGH-performance application. First off, is that in order for carburettors to work properly they need a venturi, and the associated pressure drop from the venturi effect is actually the most fact proven reason for carb icing, and why low latent heat of vaporization gasoline can still have carb icing in 100 degree weather. Now, when you combine the venturi effect with poor atomization you end up with a very localized heat transfer as the fuel makes it's lazy path to vapor. Likely a fair statement. Though most of the guys I've seen running without an intercooler with E85 and with fuel injection are still the V8 crowd. I think this is likely the fact that they run WIDE on compressor maps, with high flow and low-pressure ratio. These guys are making peak power around 6,000 in many cases, and have no issue spooling a large turbo by 2k rpm and don't mind turbo lag because of the off boost power available. There's no reason they couldn't run a setup with a higher pressure ratio, but the that starts to be a pretty serious street engine that few actually shoot for or attain. Also, a lot of the real world examples I've talked to of guys making 1,000+hp on methanol with blown small blocks and 12:1 compression aren't drag motors, they're in BOATS. And not drag boats. These are engines built to happily run cracked open producing 75% of its available power for an hour or more. I've never bothered to ask them how much they spend on fuel... But my point is that the engine builders in this market segment do this regularly and it's no big deal. They're running high compression, and no intercooler. And it's fine because of the relatively low pressure ratio. The fact they're running a carburetor should only be hurting them, as evidence that nearly all carb to efi conversions allow for more aggressive timing, which can only be attributed to fuel distribution being more even, along with in chamber charge temps being lower. Yeah, I was looking at the HX35... back when I started this thread. How many years ago was that? I was also thinking I'd be doing all this on the cheap. Last year I spend 2k on an OEM Subaru turbo for my outback. The idea of spending that kind of money on a fancy aftermarket turbo isn't a huge deal in my mind anymore. I'm also aware that I'm going to be in a fairly small group in the Z community running a setup like this. IMO, that guys issues were likely 100% tune related. Guy even says he suspects his head gasket blew from timing. I think a better example is Perrin's article on the STI engine: https://www.perrin.com/blog/post/your-sti-doesnt-need-an-intercooler-right Personally, think their biggest issue was that they were still running gasoline in the port. It'd have been a different story with E85. I say that because I've seen an STI go from 375whp range and be VERY timing restricted (as in, they go from being down 30hp to knocking within a 1 degree spread) to being 450whp and nearly not caring about timing on E85. Was it intercooled? Yes. Was it low compression? Yes. But the timing map showed that for that power level, that 2.5 liter engine would have done just fine adjusting those variables, as it had timing to spare. This is something I've considered since I'll be injecting e85 far back near the plenum. A small thermistor style sensor would be pretty easy to poke through a small hole and seal up with minimal flow restriction. Also, knock sensor would be a very crude way to measure this. The real facny way is to install in cylinder pressure sensors, but that's beyond most of our budgets. Yeah, I'm not sure it really does in the grand scheme of things. If all the fuel vaporizes, it has the same net effect. The struggle is that some engines have a hard time vaporizing all the fuel in certain load/rpm regions with carburettors. Why do you think there's always a mid range torque increase with EFI swaps on V8's? Usually a drop in peak HP is due to airflow restrictions, but that huge mid range change can't all be attributed to flow.... Now, let's look at some other maths since we're interested in known things we can actually look at and consider. For example, for any given system we can calculate INLET AIR TEMP -> Compressor Efficiency -> PSI -> Outlet Air Temp Assuming : 100 degree inlet air temp (either higher underhood temp or hot day ram air) 75% compressor efficiency (which I admit is high, but the G25 compressors reach 79 peak...) targeting 20psi boost at sea level pressure Our turbo outlet temps will be a scorching 309 degrees. Now, an intercooler that's able to achieve a crappy 50% efficiency would drop us all the way down to 203 degrees, which is "managable" and I've seen people tune around IAT temps in that range pretty often. So the question becomes "how much does E85 drop temps"? This might be hard to answer definitively with data sheets on a paper, but some of these guys seem to have foumulas that match their real world experience: http://www.modularfords.com/threads/194918-What-Is-The-In-Cylinder-IAT-Drop-With-e85 Specifically post number 11 You can see they're just doing latent heat of vaporization by weigh compared to AFR. Though maybe simple it seems to be pretty effective and doesn't try to get into "real world modifier math modifiers" to compensate for lack of initial math function viability. Now, the one thing I'd point out, is that using a lambda of 1.25 might be "ball park" for most people, but that's a bit on the lean side of your window to work with. The 1.25 figure is relating to the lambda equivalency ratio that you'd see on a chart like this: Lean max torque for E85 lands at bout 1.15 while rich max torque lands all the way up at 1.40. That's a BIG range for "max torque" let alone "will burn without issue". I've seen E85 lambda readings down to .55 without ill effect on spark. If we plug that kind of insane AFR into the calculation: 770/(9.8/1.8) = 141 (Celsius) * 1.8 = 254 (Fahrenheit) That's 250+ degrees of temp drop capability. Now, some of that will "bleed" into intake and head temp cooling, since we're not using direction injection (would would still have some loss to head temp, but a lot less overall loss since there's no time spent in the intake and no pooling at the valve). All told, that's a massive amount of cooling capacity. But even if we look at this in the more realistic realm of .7 lambda we get this: 770/(9.8/1.4) = 110 (Celsius) * 1.8 = 198 (Fahrenheit) We're still looking at enough cooling to match a crappy small intercooler, or even best it. The obvious question though is: "If you're only going to drop the temp AS MUCH AS an intercooler, why do you think you can still run high compression if the net in chamber temp is the same?" Well, the answer to that is more to do with the way E85 burns than it does temperature. In my experience, E85 burns in a much more controlled fashion and much less explosive than gasoline. This allows you to approach minimum required timing and test max available timing for peak power in much safer and controlled way. Now, if you're stupid it'll still blow head gaskets at will since running too much timing for a given condition can still create insane pressure spikes, but if you're running on a steady state dyno doing timing traces you'll see the power drop off with timing in a much broader range before detonation becomes the limiting timing factor. Overall, I expect to leave power on the table. I don't expect to win any dyno awards here. What I do expect, is to have a very responsive engine that starts up with ease and doesn't eat seals (since it'll run gasoline at start and shut down), while making more than enough power to be traction limited in almost all scenarios (trying to keep with either 225 or 245 max tire).
  7. Gollum

    180 Degree L28ET Intake

    Well let's continue by discussion with some basic parameters of the topic. This a great basis of data to work from, as it has many metrics in one spot: http://walshcarlines.com/pdf/fueltable.pdf Ethanol is approx 2.64 times the cooling capacity of gasoline, volume for volume. But stochiometric is 61% lower, so you'll run 1.63 times more volume, effectively giving you 4.3 times the cooling capacity of gasoline. Methanol is approx 3.71 times the cooling capacity of gasoline, volume for volume. But stochiometric is 44% lower, so you'll run 2.45 times more volume, effectively giving you 9.08 times to cooling capacity of gasoline. (note that we didn't factor in weight difference which is what stochiometric is based on, but gasoline also has a weight range wider than the alcohols, so it's not as relevant) This means that methanol is 2.11 times more effective than ethanol when comparing to gasoline. Now, we also have to account that we're comparing pure ethanol above, so there's also a 15% drop in all these comparisons when talking E85, which is more like E65-70 in the winter. The SR20 engine is pushing 85+ psi..., and making 1000hp per liter... (on the known post intercooler changes this year, I can't find exact specs from last season, but they weren't MUCH slower... just less consistent by a good margin) ...I'm talking about running 25psi max, likely less than 20, and making.... 500ish hp? Maaaaaybe 600 if I'm dreaming after major headwork? So ballparking the math (we having fun yet?! I am ), 1600hp divided by 2.11 would be 758HP. 85PSI would be 40PSI. Drop those numbers to 85%, and we're at 644hp and 34PSI. And well guess what... that looks REALLLY close to what I see on forums that people get on E85 with SR20s.... go figure The way I see it is that a really well-optimized L28ET should be able to reach about 200whp on pump gas without an intercooler. Plenty of people reach 180whp without an intercooler just fine. The largest problem is being within the compressor efficiency range, which doesn't take much to get outside of on the stock turbo. IF people built (and they don't) a turbo setup on the L28ET optimized for 250ish crank HP with a high-efficiency modern compressor, getting beyond the 200whp range without an intercooler might be quite possible or even common on 91 octane gasoline. Regardless of that though, my plan is to tune what I can on pump gas then tune E85, and let the ethanol sensor and map blending do its work. If I run out of ethanol, (I'm going to be dual fuel) my tune should be able to lower the boost and run on the gasoline-only map. If I'm running a nasty low ethanol content tank then it'll adjust accordingly. And if I get a good tank of E85, it should match my initial tune nicely. Also keep in mind, by the time I get around to fabbing these, I'll also be doing a bit of head work, so I'll be at less PSI per HP compared to a bone stock F54/P90 combo. I'd likely be generating excessive heat at just 10psi on the stock turbo... But the target non-intercooled HP on pump gas mentioned above would still be reachable, if not easier so. At the end of the day, I'm also not sure how much it REALLY matters to inject fuel before or after charging. There's a lot of heritage history with carbs on top of blowers, and blow through carbs were always more difficult to manage than draw through. The reason blow through was even a thing on turbocharged engines was that fuel is a lot harder on compressors than roots blowers, necessitating to not sling fuel through the turbo. One thing to keep in mind too, is that the LATER you add fuel, the FINER the mist needs to be. This has been a very real necessity with direct injection, as without a VERY fine mist you'll LOSE atomization capability over good port injection. It's also why with staged injection you're always going to run the later higher HP stage further up the airstream before the valve, to give more time for the fuel to atomize (and cool).
  8. Gollum

    180 Degree L28ET Intake

    Actually, the cooling effect would be better seen POST blower. Think about it, why do we use inter coolers (or after coolers if you need to call them that) and not pre coolers? The higher the temperature differential the easier it is to absorb the energy. What this leads to is the reality that a bulk of the fuel in these carbed supercharged engines doesn't get atomized and provide it's cooling effect until down stream, post supercharger. Also, think about the SR20 example. We're talking about a 1600+hp setup without an intercooler. They're running over 2k HP now, though with an intercooler and the engineer lead on it said himself that was a choice based on his experience when it comes to consistency, not because it was necessary... He also talks about how it's directly related to the pressure ratios seen on these smaller displacement engines, and that bigger displacement engines have the luxury of runner further right and lower on the compressor map. Considering my target pressure ratios... I'll be fine. As for BOV, that's one thing Garrett didn't include in the new G25 I'm disappointed about. Borg Warner included a REALLY trick recirculation valve in their EFR turbos that I think everyone should copy. Provides immediate built-in recirculation right at the compressor wheel which makes it ultra responsive while also making plumbing easy and sleek. See here: They also attach a boost solenoid for you too, so there's even less plumbing to worry about there as well. Overall, the EFR was designed for clean installs, and I like what they did about it. By contrast, if I use the Garrett I'll definitely wait for the wastegated hot sides to be available (currently in short supply as production ramps up) and I'll need to bring my own boost control solenoid along with BO/RecirculationV. ...then there's also the chance that G25 dynos start coming out and are disappointing and don't live up to the hype... and then I'll just go EFR instead.
  9. Gollum

    180 Degree L28ET Intake

    E85 or die bro! But really, MN47 and no cooler and I'm not even remotely phased. All my research on the topic in the last 5 years only confirms my feelings on the topic. There's plenty of big blocks running e85 with giant roots blowers pushing 14+psi and e85 on 12:1... I'm targeting 14-20psi range and lower compression. Should be fine. In fact, there's plenty of 6 second alcohol class drag cars (meth not eth) running without intercoolers... Now, the six second SR20 car is running an intercooler THIS season, but didn't last season... It's all in the tune. I might be giving up some power, and definitely giving up some fuel economy under boost (run richer to keep cooler since alcohol tolerates rich mixtures with much less power drop and spark fuss compared to gasoline) but the trade off is worth it in my opinion. Quicker boost, less plumbing, weight, and really it's about the response on the street. Should make transients much nicer.
  10. Gollum

    180 Degree L28ET Intake

    Woops, I lied. I changed the diameter of the pipe, but not the radius. Fixed it. Interior volume is down to about 2.4 liters, put the bends back to 90 degrees since the depth is well under control now. Distance in the axis the runners aim in the intake has a max length of 13". If you tape a tape from the gasket surface to shock tower it sits at about 15" as straight of a line as you can go, so this is certainly in the ballpark of "just fine" for prototype dimensions. Also, aluminum pipe dimensions are 2.25"OD with 3" radius bends for those corners.
  11. Gollum

    180 Degree L28ET Intake

    The plenum was measuring mightly close to the shock tower, plus my throttle body was based off a 65mm unit, which seemed too big imo, so I swapped out for smaller diameter pipe for the outside curves, which also use a three-inch radius bend instead of 4. I also cut the bends short, so instead of rotating 90 degrees they come out 70 degrees and then terminate, giving a more squat plenum. It might look small, but calcs are still showing it's a 3+ liter plenum. Plenty enough for a turbocharged L series imo. I might be worried if it were an all out NA build, but I don't think top end would suffer much, especially since if there are lean/rich cylinders I can adjust accordingly per cylinder as long as I know which ones they are... Also, swapped the throttle body sketches out to adhere to this generic 60mm unit: https://www.ebay.com/itm/60mm-2-36-Universal-VQ35TPS-Aluminum-Throttle-Body-Intake-Manifold-Billet-Blue/271743038867?epid=4008212244&hash=item3f4525b593:g:0BQAAOSwAuZX17pO&vxp=mtr
  12. Gollum

    180 Degree L28ET Intake

    Yeah, I did flow analysis of a similar design in SW before but I've given up on maintaining a SW installation. One of the nice things about onshape is that it's public, so if you follow my links and create an onshape account you can export the design yourself Could even copy it and make adjustments to your copy In my previous flow calcs it was really hard to get what I felt was accurate results. The problem is that flows are dynamic in any engine so you need to model a plethora of pressure differentials to really see how the intake performs in transient areas as well as raw mass WOT flow. In ANY case, the flow should be better distributed than OEM as well as most non tapered front entry designs. Judging from some of the other flow simulations I've seen, the best addition I could add would likely be a tapered entry point coming down to the throttle body mount. That would help prevent massive low pressure areas right outside the throttle inlet at that entry surface. The far side being flat is likely not as much of an issue as one might assume since there's almost always negative pressure from valve to throttle. The HIGH pressure areas of concern stem from a relationship between valve closing and runner length. When the valve closes pressure builds up and can start disrupting flow on adjacent cylinders. This is really mostly an issue with short runners at lower rpm (which is like, duh) but it's a design consideration that should be attended to when looking at drawbacks/pros/cons.
  13. Gollum

    180 Degree L28ET Intake

    More updates on the turbo model. Turbine side is now much bulkier to match the drawings exactly, and the compressor outlet extends further out, which matches pictures as well as I could (no dimensioned drawings from the front face I can find), and also extended it towards the inlet a tad. I also added the dimension for the back plate ring for the compressor, though the front edge of that isn't "realistic" as it doesn't match that diameter in a full 360-degree ring, so if I can fit what I drew then I'm on the safe side. The turbo "slug" as I call it, now matches the dimension drawing from Garrett as identically as feasible, other than the cartridge area, which is of little concern to me. Also for those curious, centerline of exhaust outlet is 2.5" back from the manifold centerline, and the turbo is clocked 15 degrees. Alignment looks great, though I also know I need to go get some shock tower measurements... But hey, what's a hammer for anyways? Also, go figure, it's MUCH easier to run the downpipe when you toss in prefabbed dimensioned pieces and just rotate to fit right (kinda like real life, knock on wood). I used two 45 degree bends and getting it to fit is trivial, though it looks like the straight between the two bends could be swapped out for a 3" length (I used a 1, 2, and 3 inch straight as seen).
  14. Gollum

    180 Degree L28ET Intake

    I took some time to get rough measurements of the block and then also refined the compressor dimensions (radial diameter was short a few mm). Keep in mind there's no oil pan modeled, but the clearance looks better than oem in several directions. Also for the record, the downpipe pictured is about 51 degrees on each bend. Not quite down to 45 where I'd like, but there's some wiggle room there.
  15. Gollum

    180 Degree L28ET Intake

    Yeah, steering shaft is what's in the model. The EFR turbo is quite a bit longer (almost 20%) plus normal rotation only, so the turbo HAS to go further forward, as you can only get the header so close to the block. Getting block dimensions to make a block mock up slug is the next step. I know the block is slightly narrower than the head in some areas but also has the PCV bulge to deal with. My steering rack dimensions likely aren't perfect, but probably +/- half inch, which I could easily adjust for at the manifold output plane come time to fabricate. Also, it helps that the G25 is TINY. If Garrett makes good on it's claim the g25-660 will be the smallest turbo capable of breaching the 600hp range (that I know of at least). The G25 turbos are SMALLER than the stock L28ET turbo...