DAT240Z Posted September 30, 2003 Share Posted September 30, 2003 I would like to know what you guys think of this turbo engine idea. I would like to put my p-90 head on a f 54 block with top pistons, I will swap the oil pan to a turbo pan. The one think I have not figure out yet is what to do about a knock sensor. I was looking up engine build combo on this program lengine, buy putting the p-90 on a f 54 flat top piston will give 8:5:1 compression. I just wonder if this would be a good set up, please all input are welcome. Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted September 30, 2003 Share Posted September 30, 2003 I was thinking about going with the same type of setup in the future. I don't even use my knock sensor. You can also use a 2mm head gasket to lower the compression a little bit. Your engine management has to be tuned right though. I may not do it until I'm running haltech or SDS. Quote Link to comment Share on other sites More sharing options...
DAT240Z Posted September 30, 2003 Author Share Posted September 30, 2003 So Dale, You don't think the stock management system could handle the increase in compression? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 30, 2003 Share Posted September 30, 2003 I wouldn't try it... even if it could handle it you wouldn't have anywhere near as much flexibility in raising the boost... why bother though? It's so much more worth it to stick with low compression and have all that headroom available for increased boost, and you'll definately get much larger power gains from that than you would by going higher compression. Now on the flip side, if you do go with a fully programmable EFI setup then it may not be such a bad setup, you're still going to lose some flexibility with the boost I would think, but could probably run enough to have a serious street car, and with the higher compression your throttle response and power off the boost would be much improved. Quote Link to comment Share on other sites More sharing options...
fl327 Posted September 30, 2003 Share Posted September 30, 2003 It would be an awesome setup, my good friend runs 8.9 cr- flattop f54 with 030 shaved p90 for 8.9 cr. 18btdc on stock 83zxt efi and 57trim hybrid turbo, dynoed 260hp@10psi and almost 300ft. Lag is non existant, guy gets full boost by 2600. He drives the car hard and very often- whats the point if you dont??? Stock headgasket. I have seen this with my own eyes and been in the car driven hard, not only does it survive-it kicks @55. You do have to do a lot more tuning, if you were going to raise the boost up you would have to do it anyway. Only reason I didnt go this route in the first place, but when I did the car I wasnt thinking about hp- I wanted an efi z that was kinda quick-I found out quick this car could be more than quick, but I did something right and engine has taken 18psi with no intercooler on a fluke and bearly even sneezed at it. Quote Link to comment Share on other sites More sharing options...
DAT240Z Posted October 1, 2003 Author Share Posted October 1, 2003 Hi guys will the stock turbo dissy fix in the non-turbo block. This is what i would like to buile f54 flat top bolck turbo dissy pull my p-90 head with everything attached and bolt it to the block stock headgasket supra intercooler stock FEI scotties downpipe 3" exhaust LSD 78 5sp I'am i forgetting anything? Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 1, 2003 Share Posted October 1, 2003 Hi guys will the stock turbo dissy fix in the non-turbo block.This is what i would like to buile f54 flat top bolck turbo dissy pull my p-90 head with everything attached and bolt it to the block stock headgasket supra intercooler stock FEI scotties downpipe 3" exhaust LSD 78 5sp I'am i forgetting anything? im pretty sure you will need the turbo oil pump, and that long spindle thing that goes to the bottom of distributor shaft, NA dist has a plastic gear thing on the bottom, turbo one doesnt. that should run good for you once you get it dialed in. Im too cheap to buy aftermarket pistons, ive been messing with chevys for a long time and when I see 100 slugs I get uncomfortable. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 2, 2003 Share Posted October 2, 2003 okay it CAN be done with stock EFI but your'e still gonna need some way to tune it for increased fuel and retarded timing... but when you add those things it's not really 'stock efi' anymore. I guess with minimum of... RRFPR and maybe one of those units that MSD makes that retards timing under boost, you could safely run flat top pistons and more than the stock 7psi of boost... That would make an awesome setup... Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 2, 2003 Share Posted October 2, 2003 okay it CAN be done with stock EFI but your'e still gonna need some way to tune it for increased fuel and retarded timing... but when you add those things it's not really 'stock efi' anymore. I guess with minimum of... RRFPR and maybe one of those units that MSD makes that retards timing under boost, you could safely run flat top pistons and more than the stock 7psi of boost... That would make an awesome setup... Not really. True-you are taking more of a risk running the higher cr with stock efi, but it can be done with a bone stock efi setup if you pay great attention to tuning, and dont try to go RAMBO and turn up the boost right away. Initial timing may have to backed off a bit, 18btdc being what was run. Stock SIZED injectors are used-----BUT, they were good injectors, from RC or whereabouts (soon to be in MY car)=this is extremely important in any boost application, that the injectors are not a NAPA or AUTOZONE type injector- if you compare spray patterns, the NAPA/ZONE ones often dont compare, and its known if you order for turbo, the goober behind the counter may try to sneak you a NA one thinking it will be ok. Not good. Quality parts and a lot of NISSAN sensors and a over achieving efi setup (best ive seen swapwise) are used, and dyno time as well-Last time I saw the guy he pulled the dyno slips out of his glove box!!! Does a Walbro fuel pump and stock 240z tank count as stock efi? Of course, it is hotwired to a relay. He used excellent parts and did his homework thats forsure, but he doesnt have any magic wands or fairy dust to achieve this. No rising rate fpr, stock regulator was used. No timing retard device either, but MSD 6al was used, and its not a bad idea to boost ignition in any forced induction application-thats a given. FUel? Air? the guy ran 13.2 with 16psi of t3 through a starion intercooler!! TUNING Ok fine, I think he told me he was detonating big time on top end with it-which stopped when he went bigger on the IC and TURBO-he runs times close to his t3 times with 10psi instead of 16. Of course he is limited as to how fast he can go, and is installing Haltec as we speak to bury into the 12s and better. Results like this, of course cannot be guaranteed to match these, but with tuning and patience, I cant see why not. 8.5cr is perfect for turbo charging I think, really healthy lowend to replace what a oversized turbo makes up for on mid and top end, just makes sense to me. Hondas run 10-1cr and they turbocharge all the livelong day, yeah I think they suck, but it tells me its possible. It really isnt much harder than setting up the stock turbo motor for good hp numbers, I think the higher cr makes it easier to get the good numbers, and it will run just as good as the stock one does as long as you tune with patience. Best believe, next engine that goes in my car will have a cr of at least 8, if there ever is a next engine, sucker takes a kicking and keeps on kickin it like Bruce, watch when he gets LOOSE.. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 2, 2003 Share Posted October 2, 2003 Yes, Hondas run 10:1 turbocharged because they have to. And lots of applications run 8.5:1 compression ratios and do just fine. The Supras run 8.5:1 as well as the Skylines. But a lot of that has to do with head design as well, and the Hondas MUST run intercoolers to run more than 6 psi boost. If you don't care much for off-boost response, lower compession is better, as you don't have as much heating of the mixture from compression inside the cylinder. The power potential is greater with the factory 7.4:1 compression ratio, and with a T3 turbine, lag or off-boost response is not an issue. If I ever need to build up a L28ET, I may bump it to 8.0:1, but I'm just happy as a clam with 7.4 Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 2, 2003 Share Posted October 2, 2003 Factory turbo motor is good, thats for sure, its cr is ridiculously low for me. Once I get the new turbo on, we'll see about off boost response, its close to hat Jtaylor is selling here, but I got BALL BEARING OPTION!!!! Does the flat top combo work? YES. My engine still runs close to factory compression, and I like it with the t3, will I like it with the big dog turbo, we will see. I like higher compression, and Ive seen too many examples of 8 and above cr on turbo L motors to be discouraged. Quote Link to comment Share on other sites More sharing options...
Guest butlersZ Posted October 3, 2003 Share Posted October 3, 2003 What about Tod Kanekos '72 240 ? It has 8.5-1 CR , E88 head with 40cc chambers, Bores and stroked to 3.1 liters, Prototype turbo with 84 trim (68mm) wheel in a t-31 housing and a 56 trim (82mm) wheel for the compressor side, HKS intercooler, 720cc injectors and DTS engine management. I think he runs about 35 psi of boost, but man is it tuned! 500 HP! And the pistons are flat tops. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted October 3, 2003 Share Posted October 3, 2003 A cam can alter the dymanic compression. I think ultimately, you should be aiming around 150psi cylinder pressure or so. 8.5:1 would prolly make more power with lower boost level but even with lower compression, you can make close power with more timing. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted October 3, 2003 Share Posted October 3, 2003 We threw a JY N42 flat-top engine in my friend's car with a stock T3 and a Z31 efi system. It runs great and has good off boost response. No IC- no knocking or pinging. It is running 7 psi right now - going to an IC and 10 psi this winter. It works - just try it. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 3, 2003 Share Posted October 3, 2003 I dont think anyone is debating that it works... just debating the benefits versus the drawbacks. Those turbo hondas with the high compression are very limited in the amount of boost they can withstand plus the stock honda blocks are considered pretty weak and wont take a lot of boost for sustained periods anyways, I hear 6-7psi max off an I/C maybe up to 10psi with an IC... even with good programmable EFI they really can't take much more than that or so I have read. I agree that with the much less advanced design of our L series heads, we dont have the same freedom to mix higher compression and high boost as something like a skyline engine! For a guy like me, who will probably only ever run 10-12psi max boost on a mostly stock engine and EFI, running a higher compression would probably be fine, no big trade off for me, and for guys who want big numbers with big turbos and programmable systems they can probably get away with it easily too, but I think they're gonna be more concerned about leaving that extra head room for more boost... they dont care as much about off the line acceleration as that big top end. For a mild streetcar I think it'd be perfect though now that you guys have dispelled some of the myths... if I ever build another motor I'll probably go flat tops but stick with the stock P90. Still think I'll need a way to richen the mixture and wouldn't feel safe w/o a way to retard the timing under boost though.... Quote Link to comment Share on other sites More sharing options...
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