letitsnow Posted October 12, 2011 Author Share Posted October 12, 2011 I have, the coil, an MSD blaster 2, was bought new for this car when I first put it together. It has maybe 10k on it now. I did borrow another one just to check, with no change. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 15, 2011 Author Share Posted October 15, 2011 Ok, fuel pressure sensor needs to be wired up, all code changes in the .ini are done. and I'm heading out to start of the hydraulic to mechanical swap. It appears that the 1/8" npt port on my fuel rail was cut too deep for anything but a plug to seal up(actually all the npt ports are too deep on this rail). My fuel pressure regulator has a port I can use, anybody see any issue with that? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 15, 2011 Author Share Posted October 15, 2011 Fuel pressure sensor is wired up, here is a log with fuel pressure-28psi vs boost pressure. The red arrow is where it fell off. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 15, 2011 Author Share Posted October 15, 2011 (edited) The first picture picture is the same as before, but with the derivative of RPM as the purple line in the top graph. The second picture is at 8psi, the first at 12psi. dRPM falls from ~500 to ~200 on the 12psi run, just to give you an idea of the power loss. Gap is now .022" Edited October 15, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 16, 2011 Share Posted October 16, 2011 I'm not sure what you are trying to show with 'delta rpm'... Or what you mean by 'where it fell off' after the red arrow, I don't see any 'falling off'...what fell off---everything looks like it remains basically like it was before. RPM falls 500-200rpm in relation to what? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 16, 2011 Author Share Posted October 16, 2011 (edited) deltaRPM can basically be considered acceleration, calling it 'delta' was probably incorrect. I was trying to demonstrate how the power goes away rather abruptly. I think the units for deltaRPM should be RPM/sec, or somewhere near. The drop from 500 to 200 shows that after that point, it's making ~2/5 the power it was, yes it's a VERY rough estimate, but I thought it might describe what I was feeling better than just saying power fell off. Here it is again, but with some rather crude, but aggressive filtering. Edited October 16, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 16, 2011 Share Posted October 16, 2011 You mean this is a RATE? RPM/SEC or something like that? At 8psi you accelerate at 500 rpm/sec to 5969 rpms past the red arrow... Opposed to: At 12 psi you accelerate at 200 rpm/sec to 5969 past the red arrow... ?? I mean, if I'm understanding you correctly you are saying that the engine doesn't accelerate well past torque peak, and accelerates harder in lower gears than higher gears (according to the chart...) This is to be somewhat expected. Do you have something like a G-Tech that graphs instantaneous G's? I found that to be a CRITICAL piece of equipment when learning how to change the way I drove my stock-cammed blowthrough turbo. By shifting to optimize G loading for acceleration I found the wive's tale of shifting at stratospheric levels was COMPLETELY a waste of time, and that if I shifted by 5500, or in some cases 5000rpms (which felt like a VERY 'short shift' in gears 2, 3, 4 that the instantaneous G's of acceleration were MUCH higher than if I held shift point past 5000 in ANY gear. What you may be experiencing is simply the function of the stock cam telling you "SHIFT EARLIER" and you will accelerate harder. Wanting to shift at N/A shiftpoints only is applicable when you have a cam matched and suited for revving like that. My best acceleration times at the track with the stock cam came with a first gear shift at 6500, and upshifts at 5200-5500, 5000, 5000. It's a really counterintuitive way to drive the car given how it accelerated in 1st gear, and even second. But after 2nd gear it really seemed to like short shifting to pull with higher G's. May want to look into this in that respect. It sounds a lot like it's doing what 'they all do' to some extent and you may be trying to 'fix' something that is driving technique based. I never had great "pull power" above 5000 in any gear above 2nd. You're just too far past the torque peak, and the VE of the engine on-boost is commanding you to shift like a Big Block 454. Boring as hell, but effective. The G-Tech was what changed the way I drove it. I could not argue with the instant readout. YOu can probably get the original 'black box' like I had now on E-Bay used for $10. It's a neat gadget if for nothing else to tell you how hard you are ACTUALLY accelerating. And I think that would be equivalent to your RPM/Sec rate-of-change example. That should be mathematically derivable from weight of your vehicle and acceleration of RPM/Sec Change. This may be a 'problem' that is unsolvable. It may be inherent in the cam profile, and may be exactly what I experienced if I'm understanding what your graph is showing. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 16, 2011 Author Share Posted October 16, 2011 (edited) I believe it does fall off naturally because of the cam, but I don't think the 12psi graph is normal falling off. The 8psi graph doesn't have the sharp drop off at 4700 like the 12psi graph. If it was a smooth-ish drop I'd accept it, like the 8psi graph. It's not a consistent drop in power, sometimes I do get a clean 3rd gear pull, no sudden drop in power. I'm VERY confident that they don't all do it. Edit: the average for the 8psi graph is ~315, the average for the 12psi run AFTER it falls off is ~205, I see no reason why the power(or RPM/sec) should be lower at a higher boost in the same gear at the same rpm. The timing doesn't do anything funny at that point either. It does it in every gear too. Edited October 16, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 16, 2011 Share Posted October 16, 2011 IF you're off the chart of efficiency of the turbocharger it quite possibly could mean you are not pushing the same Pounds Per Hour through the machine... The added heat out of the turbo at 12 vs 8 could start to negate the perceived gains. When I used a stock turbo, I originally tried 17psi, and that didn't work at all. Eventually it was settled on around 11-12psi was my "high boost" setting. But generally at 10psi is lasted forever and pulled almost as strong. 36+12=48psi at the rail insofar as fuel pressure goes, that leaves you with no more than 12psi line drop before the stock fuel pump goes into bypass---which would explain the different passes you get. This is also why I said to check the fuel pressure upstream of the fuel filter. If you have 8psi line drop (typical) you're already at 56psi at the pump on 12psi. If your filter has any appreciable drop in it, this could make pulling upper end harder. Then again you would expect it so show lean---which brings back the question of if you're trimming fuel above torque peak? You can pull fuel pretty hard after torque peak and you keep picking up power. The stock system went lean at the very top end, a little too lean, but most guys think running 11.8 AFR across the board will net them power, and that's not the case past torque peak. Pull it back to high 12's or even mid 13's and you will continue to see a power increase. Really at this point instrumentation has to be watched, and keep all your graph scaling the same so you can do actual comparisons of apples-to-apples when it comes to rates and pressures. When they are normalized to the same scale, SOMETHING will jump out at you. At least it should. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 16, 2011 Author Share Posted October 16, 2011 I think I found the problem, video incoming after I get a bite to eat and the camera charges a little. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 17, 2011 Author Share Posted October 17, 2011 I was all ready to put it back together, then I found out that the threads for one of the cam tower bolts was stripped. Hopefully I can find a helicoil kit, and not **** it up. I think this is the last week the track is open for the year. When I took the ones that were collapsed out, they sprang back and felt normal. I think the spring binds in the body. I decided to still convert to solids. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted October 17, 2011 Share Posted October 17, 2011 I was all ready to put it back together, then I found out that the threads for one of the cam tower bolts was stripped. Hopefully I can find a helicoil kit, and not **** it up. I think this is the last week the track is open for the year. When I took the ones that were collapsed out, they sprang back and felt normal. I think the spring binds in the body. I decided to still convert to solids. Wouldn't this problem have valve clatter at the time of occurrance due to wide valve clearence while the HVA is not working correctly? Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 17, 2011 Share Posted October 17, 2011 I would think soooo. I can't view what's on the video here, so it's nothing I can comment on. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 17, 2011 Author Share Posted October 17, 2011 (edited) loud turbo and exhaust could easily hide it, the turbo is LOUD. The oil pressure might pump it back up enough so that it doesn't clatter much, but won't open the valve. Really there are a ton of things that might make it do weird things, but that's not going to stop me from finishing the conversion to mechanical adjusters and an N/A cam, my confidence in these hydraulic adjusters is gone. It does clatter at idle somewhat, sometimes more than others. In the video, I grab the pivot ball of 5 HLA's(4 separate cylinders) and move them up and down through their full stoke with no effort at all, gravity would take them back down from the fully extended position. Edited October 17, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 17, 2011 Share Posted October 17, 2011 Sounds like the lifters are freely moving at least! They should pump-up with oil pressure as long as sufficient flow and pressure exist. And that should be the condition at 4500+ rpms. The hydraulic pressure provided by the oil pump, plus the cross sectional area of the pivot's plunger would exert considerable upwards force. But those things should be SILENT at idle. If they are clattering, you are loosing oil pressure to an extent that it won't support the lifters. On an 83ZXT with the lifters the injectors clicking is all you hear at idle...with the occasional burp from the bullfrog pump. I think you have an oil pressure problem which may or may not be cured by the mechanical changeover. The N/A cam (depending on which one you get) will either be similar, or noticeably different up top from the turbo cam. The comparison of power before-and-after will be somewhat skewed replacing them both at the same time but what else can you do? Good Luck! Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 17, 2011 Author Share Posted October 17, 2011 (edited) The piston is how big in the adjuster? I'd say a MAX of 5/8". Assuming 75psi of oil pressure, 3/4" dia piston, I calculate that it's got maybe 33lbs of upward force, in my little best case scenario. 75*(.375^2*3.14)=33.11 How heavy is the spring in those things? I couldn't budge them by hand, so I stuck one in the vise with a piece of wood on either side for cushioning, it crushed the wood and didn't budge the adjuster a bit. Hopefully I can grab a helicoil kit today and get that cam tower bolt fixed, that certainly wasn't helping anything. The stock gauge reads over half way up the scale at cruise, it is questionable in accuracy though. I'm confident in the bearing clearances being alright, but maybe the pressure relief spring in the pump is weak. The cam is from, a '77 280z, so it should be the 'A' cam everyone says is an upgrade. AtlanticZ.ca says it has 8 degrees more duration and nearly a mm more lift. Edited October 17, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 17, 2011 Share Posted October 17, 2011 Yes that cam will help past 5k for sure. The torque peak I'd higher. The pressure plus spring pressure would be what you have. For some reason your springs seem to have failed. And that is enough to cause the issue at idle...maybe allowing movement and variable geometry at the higher toms as well.... Like I previously said: what else can you do? I am definitely NOT a fan of elevated oil pressures! Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 17, 2011 Author Share Posted October 17, 2011 (edited) They knob that put the head together stripped BOTH the bolts on the center cam tower. I've got them repaired now, so in an hour or so I should have it back together and ready to take for a spin. Edit: make that 5 total stripped cam tower bolts Edited October 17, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 18, 2011 Author Share Posted October 18, 2011 (edited) Well, on 7.5-8psi it feels very strong all the way up to 6k. After I nail the tune down we'll see how it does on 12. *crosses fingers* Question: cam tower alignment, with all the M8 bolts torqued down, the cam spun pretty freely, after torquing the head bolts, it was pretty stiff, it took 2 hands to turn. Should I take it back down and try to get it to spin more freely? Edited October 18, 2011 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 19, 2011 Share Posted October 19, 2011 That would seem to indicate a warped head more than anything else... Bet Tool Boy lubed up those cam tower bolts 'real good' when he torqued them... Well, speaking of Tools...I have to go sink a couple of 5/8-11 Helicoils into a gearbox and then have the locals hail me as Conquering God of Metal by saving them $120K replacement costs for a new gearbox... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.