projekz Posted January 14, 2013 Share Posted January 14, 2013 Has anyone built a high compression VG33? If so I'm interested to know what tuning options are available to get the proper timing and fuel maps on the car. this would be for a 1997 R50. Thanks Link to comment Share on other sites More sharing options...
Nefarious Posted January 14, 2013 Share Posted January 14, 2013 Look up project pathfinder in the search. They build a vg34 with higher compression using vg33e block and machining it out to fit q45 pistons Link to comment Share on other sites More sharing options...
Nefarious Posted January 14, 2013 Share Posted January 14, 2013 Keep in mind the stock ecu and fuel system won't support a high compression build. U will need at least injectors and a tune Link to comment Share on other sites More sharing options...
Kingman Posted January 14, 2013 Share Posted January 14, 2013 Sure it will. TBI runs a 10.5:1 VG34 just fine. Link to comment Share on other sites More sharing options...
Nefarious Posted January 14, 2013 Share Posted January 14, 2013 (edited) Really? Well then I guess I'm wrong. I don't think I would want 180cc injectors on a high comp vg34 build but I'm sure if u crank up the duty cycle on them it shouldn't run lean Running larger injectors at a moderate duty cycle is better than running smaller injectors at a high duty cycle, I would also upgrade the maf as the tiny stock maf would be a huge limitation with that much potential air flow! Edited January 14, 2013 by Nefarious Link to comment Share on other sites More sharing options...
Nefarious Posted January 14, 2013 Share Posted January 14, 2013 (edited) I thought q45 piston in a vg33e made 9.6;1 compression, up from the stock 9.1;1? I'm pretty sure that's what project pathfinder had reported anyways. The stock fuel system could adapt to that easily. Where is the 10.4;1 from? Edited January 14, 2013 by Nefarious Link to comment Share on other sites More sharing options...
Kingman Posted January 14, 2013 Share Posted January 14, 2013 http://www.nissanpathfinders.net/forum/topic/31418-building-a-vg34-and-installing-it-in-my-88-pathy/ Link to comment Share on other sites More sharing options...
MY1PATH Posted January 14, 2013 Share Posted January 14, 2013 The size of the injector has less to do with compression ratio than you think. At arround 225HP your will start to run into limits with a pathfinder and those are yes, injectors due to RPM and displacement an running the injectors at a high duty cycle. but before that you fade out arround 200 hp because of the design of the MAF housing on the wagons and pickups. Both these numbers are quite a step up from the 150 hp and 180 hp vg30 and vg33. I am currently building a higer compression vg33, the cheap way; 0.050" will be taken off the heads and this will yeild a .5-.75 increase in compresson. (I'll have exact numbers once I get the head back and I can CC it) Compression does not make dramatic increase in HP like you would see above. One point in CR on a VG is worth maybe 4 HP.The real benifit is the flattening of the torque band (Feels faste lower sooner and longer) and increased thermal efficency (ability to turn heat into energy) Both of these offer enhanced driving experience and improved fuel econmy while keeping fairly close to the same HP numbers. Now If you are planning on going over 200HP I recomend switching to the N60 (m30 and maxima) MAF and using 270cc injectors. (If you do not have nistune or any way to tune MAF changes must be balanced with injector changes.) At this point your horsepower celing for air and fuel will be about 300 and Higer if you get into tuning. Upgraded MAF does not mean more fuel, it means Higer resolution reading of the air passing thru. So If the 270cc injectors are too rich with the N60 MAF then use the N62 MAF (z32 and Q45). Link to comment Share on other sites More sharing options...
MY1PATH Posted January 14, 2013 Share Posted January 14, 2013 I thought q45 piston in a vg33e made 9.6;1 compression, up from the stock 9.1;1? I'm pretty sure that's what project pathfinder had reported anyways. The stock fuel system could adapt to that easily. Where is the 10.4;1 from? stock vg is 8.9:1 MR510 built a vg34 and it came out to 10.3:1 I think some have been assembled with out cutting valve relifs (or not as deep) for 10.4:1 but they make it at etremely close tolernace. Float a valve and your done. Link to comment Share on other sites More sharing options...
MY1PATH Posted January 15, 2013 Share Posted January 15, 2013 In theroy, if you combined my headwork with a vg34 you would have 11.5:1 This would be kickass for an NA VG. Gee, maybe I sould do that next... Link to comment Share on other sites More sharing options...
Nefarious Posted January 15, 2013 Share Posted January 15, 2013 yeah that would be amazing. im still confused why project pathfinders detailed build listed the compression increase as .5 over stock, maybe they were wrong who knows. i am definitely planning more than 200 hp on my vg33e swap so larger injectors/maf are a must. i am just saying i personally wouldnt run stock injectors on a high compression 200+ hp build. i would feel much better with running larger injectors on a lower duty cycle, and making not only more but smoother power when coupled with the larger maf and a rom tune. makes a lot more sense to me to do it right and have everything working together in harmony than just let the stock tune try and keep up with the massively increased air flow Link to comment Share on other sites More sharing options...
MY1PATH Posted January 15, 2013 Share Posted January 15, 2013 (edited) Their article http://www.motoiq.com/magazine_articles/id/1298/project-pathfinder-part-10-how-to-build-the-nissan-vg30e.aspx says from 9:1 (8.9 rounded up) to 9.6 "The Q piston domes must be slightly modified with notches for valve clearance. We had a local machine shop duplicate the VG’s valve notches on the Q pistons." They started with a VG33 block, they had the machine shop duplicate the (huge) reliefs in the vg33 pistons. If a VG33 pistons had the same cuts as the vg30 pistons they would be about 9.75:1. I think in MR510's build he cut reliefs samaller than you would find in the vg30 pistons. Edited January 15, 2013 by MY1PATH Link to comment Share on other sites More sharing options...
Nefarious Posted January 15, 2013 Share Posted January 15, 2013 Ah I Gotcha, okay that makes sense. Smaller than vg30e dishes eh, yikes don't mess up a timing belt job hey? Lol Link to comment Share on other sites More sharing options...
MY1PATH Posted January 15, 2013 Share Posted January 15, 2013 (edited) He builds VG's for a living. I think he was able to assemble and test to find out that stock relifs were more than what was needed. reliefs serve a secondary purpose of acheiving a target compression ratio so that the MFR can better acheive and emission standard. I think That's why the only 10:1 oem VG was an NA VG30DE with 4 valves per cyl, and 2 egr (one on each side), variable valve timing and a super computer for an ecu. (z32 ecu nissan's most advanced) Edited January 15, 2013 by MY1PATH Link to comment Share on other sites More sharing options...
Nefarious Posted January 15, 2013 Share Posted January 15, 2013 Yeah I have a z32 1990 hard top in black n/a 5 speed 3150 lbs lightest z32 ever made. I love that car, its my next project.. anyways yeah I had no doubt about Mr510s skills, just an assumption! I believe its 10.5;1 at that! Link to comment Share on other sites More sharing options...
Tungsten Posted January 15, 2013 Share Posted January 15, 2013 (edited) As far as the ECU goes... If you have an early Pathfinder with an OBD 1 you can pretty much extract the old ECU and put whatever else you want if you are unhappy with the stock tune and it will be street legal. With OBD 2 you can do the same but you may have trouble passing inspection because they have to connect their own computer to the port. Edited January 15, 2013 by Tungsten Link to comment Share on other sites More sharing options...
projekz Posted January 15, 2013 Author Share Posted January 15, 2013 I have no inspection to worry about here. I'm looking for some more power on the highway so I don't have to take overdrive off on every hills. It might be more cost effective to sell my R50 and buy one with a VQ35. I'll probably just learn to live with what I have. Link to comment Share on other sites More sharing options...
Tungsten Posted January 15, 2013 Share Posted January 15, 2013 (edited) I would go the VG34E way instead of getting a VQ35DE. You get an iron block instead of aluminium and only one set of cams to worry about instead of two. Efficiency wise I expect the VG34E to perform better because in theory it should have more low end torque than a VQ35DE. The older VQ powered Pathfinders manage to only eek out an average 14 mpg. With that said, getting a different truck is definitely not a bad idea if you have limited time and resources. That really depends on how good you want it and how much time you can spend on it. Edited January 15, 2013 by Tungsten Link to comment Share on other sites More sharing options...
projekz Posted January 15, 2013 Author Share Posted January 15, 2013 Being my daily driver, the last thing I want is an unreliable engine (mostly because I'd be worried about the tune). Link to comment Share on other sites More sharing options...
MY1PATH Posted January 16, 2013 Share Posted January 16, 2013 I have no inspection to worry about here. I'm looking for some more power on the highway so I don't have to take overdrive off on every hills. It might be more cost effective to sell my R50 and buy one with a VQ35. I'll probably just learn to live with what I have. MR510's VG34 is running TBI and it handles hills just fine. I can only expect more for an MPFI vg34. It that is out of your budget you can do a "simple" 3.3 swap like I am. remember to swap over your 3.0 cams into the 3.3 heads (3.3 cams are the weak) If you are well connected you may be able to get some Nissan Euro spec cams for 50-100 a stick (nissan wants to liquidate them) These came stock in the european 3.0 and provide 10 extra ponies for Higway driving (15+ if you put them in a 3.3). If you decide to shave .50" off your head while your at it you will be getting sligtly more involved AND I will have to call you a coppy cat... (I'll have results to share with everyone in about a month.) But if you beat me too it, you need to modify your t-belt tentioner to take up more slack or your belt will not get tight enough. Being my daily driver, the last thing I want is an unreliable engine (mostly because I'd be worried about the tune). VG=Reliable Nissan used VG engines in cars and trucks for 20 years! Change your oil, keep your air filter clean and MIND YOUR TIMING BELT! and you will see 250-300k easy and it only goes up from there! The VQ engines have stepped rings and many of them start to lose compression and burn oil before 180k... (my first clutch lasted longer than that) VQ engines. The top ring is closer to the crown so they aloso have a reputation of blowing ringlands when pushed hard. These are the reasons I am not using vq30 pistons to build a vg36 stroker. 2 Link to comment Share on other sites More sharing options...
JamesRich Posted January 16, 2013 Share Posted January 16, 2013 If you decide to shave .50" off your head while your at it you will be getting sligtly more involved AND I will have to call you a coppy cat... (I'll have results to share with everyone in about a month.) But if you beat me too it, you need to modify your t-belt tentioner to take up more slack or your belt will not get tight enough. If you shave that much you will need more than a new tensioner! I'm sure you meant .05. Won't you need adjustable cam gears too to get the cams back where they need to be? James 1 Link to comment Share on other sites More sharing options...
krmiller07 Posted January 16, 2013 Share Posted January 16, 2013 (edited) Absoulutly ! Edited January 16, 2013 by krmiller07 Link to comment Share on other sites More sharing options...
Tungsten Posted January 16, 2013 Share Posted January 16, 2013 I'm not a fan of decking the block and shaving the head but if you do go that route the timing will change completely. Not to mention that you will also be bringing the valves closer to the pistons. There will be much less allowable clearance before the pistons ram the valves. Link to comment Share on other sites More sharing options...
MY1PATH Posted January 16, 2013 Share Posted January 16, 2013 (edited) Tungsten, lets not forget I have done LOTS of research in this and it WILL BE RELIABLE. The valve reliefs in 3.3 pistons is more than you could possibly need for any type of cam or timing change etc... The timing will NOT be thrown off completely, It will be retarded 1.17 degrees. this will slightly improve highway driving slightly but there is so much else going on with my engine (higher compression, euro cam, bigger pistons, heavier flywheel, Cleaned up exhaust ports) That you are not going to notice an difference in timing. You may not be a fan of it and that's fine. It can still be done and it can still be done safely. James, your right, I meant .050" The stock Gasket is .050" compressed and I did an assembly without the gasket to check everything for fit. The only things that needed attention were the timing belt tensioner maxing out and being just barely tight enough and the intake ports mismatching slightly which can be corrected by using 3.0 gaskets instead of 3.3 gaskets. About .070" can be removed from the head in a vg33, you are more at danger of cutting up the valve seats when you machine it you are of hitting the 3.3 pistons with the valves. I do not know what else mismatches @ .070" but your timing retard will be roughly 1.65 degrees and you will start wanting to use cam gears to correct that. The formula is 0.928deg cam retard per 1mm of head reduction. Edited January 16, 2013 by MY1PATH Link to comment Share on other sites More sharing options...
Tungsten Posted January 16, 2013 Share Posted January 16, 2013 Yeah I wouldn't mind some experimentation. I would like to see your results. How are you going to adjust the ECU to get the timing back on track? Link to comment Share on other sites More sharing options...
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