stav2201 Posted March 19, 2013 Share Posted March 19, 2013 I was told about a little trick you can do to the stock 280z Head to pump out a little extra horsepower. The person explained that you take a stock N-47 head and raise the valve train up .030 with these spacers called "head savers." Adjust the valve lash to the point where the lobes wipe will just barely hit the edge of the rocker arms. You then have to raise your fuel pressure up 3-4 psi, adjust the airflow meter 4 click back, and then advance the timing to 30 degrees if i remember correctly. its supposed to get you a reasonable ammount of extra power for not having to do any major overhauls to the engine. Can anyone shed any light on this or extra information, or what it is called? Quote Link to comment Share on other sites More sharing options...
z240 Posted March 19, 2013 Share Posted March 19, 2013 (edited) Study more, alot more, about how the various engine tuning parameters affect performance before doing anything else. Someone is selling you a bill of goods. If they offer you an add-on fuel line device to increase fuel mileage, run, don't walk in the opposite direction. Edited March 19, 2013 by z240 Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 19, 2013 Share Posted March 19, 2013 You can change the lash pads to get the wipe pattern, no need to shim the cam towers up. 30 degrees of timing total is a bit on the light side. 30 degrees at idle is way too much. Can't tell you anything about the AFM mods, although I did something similar on a Toyota I owned and felt absolutely no change afterward. Quote Link to comment Share on other sites More sharing options...
stav2201 Posted March 19, 2013 Author Share Posted March 19, 2013 You can change the lash pads to get the wipe pattern, no need to shim the cam towers up. 30 degrees of timing total is a bit on the light side. 30 degrees at idle is way too much. Can't tell you anything about the AFM mods, although I did something similar on a Toyota I owned and felt absolutely no change afterward. He did say somthing about swapping out the lash pads to thinner ones if i couldn't raise my rocker arms high enough, but he said using the spacers on the cam shaft journals should work fine. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 19, 2013 Share Posted March 19, 2013 Which edge? It's changing the cam timing of valve events. LOTS of work for bullsh*t return. Buy a cam regrind for $100, using a 460 lift and you will have more power with less hassle. Better yet, go out to dinner with a friend and do a proper performance tune-up and you will likely recover more HP. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 19, 2013 Share Posted March 19, 2013 Different cam isn't allowed in ITS, but yeah, if you're not running Improved Touring then just get a bigger cam. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted March 20, 2013 Share Posted March 20, 2013 Oh, I see, you're just trying to get a little more ratio from the rockers. I don't see there being a noticeable improvement. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 20, 2013 Share Posted March 20, 2013 "Replacement" cams are allowable if they conform to stock specifications. There are plenty of "stock spec" cams out there that pass tech inspection but give better performance than the stock Nissan Bumpstick. Like I said, "it's a lot of work" and I don't run IT, I wouldn't waste the time if I was, I'd use the stock-spec regrind... There are plenty of Chevys running "launcher" cams that induce valve float, butconform to all duration and lift. Specifications of the OEM. Nissan never provided ramping rates, and you play with that...you can do a lot, just liketheclaimer Chevys! Quote Link to comment Share on other sites More sharing options...
johnc Posted March 20, 2013 Share Posted March 20, 2013 As mentioned above, the SCCA Improved Touring rules require stock engine internals, cam, valvetrain, etc. There is no value in doing IT specific tuning to an engine that is not limited by the IT ruleset. Its A LOT of work for a minor gain in horsepower. You can get all of that and a lot more with the aftermarket cam mentioned by Tony above and by installing a Megasquirt EMS. All that being said, the best SCCA Improved Touring L24 engine I know of made 208hp on a SAE certified/correct engine dyno. That engine won the ARRC two years in a row. To have that engine built today expect to pay about $8,000. You can have an engine built using aftermarket parts that matches it in horsepower for about $3,500. FYI... The 280Z is not, and never was, competitive in ITS due to the weight required and you can pull more horsepower out of an IT spec L24 then an IT spec L28 because of the rpm you can spin the L24. Also, the tricks mention in the first post are correct and IT legal except the timing was generally run at 36 degrees all in by 3,200 rpm with a straight line advance (no curve). Vacuum advance blocked off and advance plate welded. Quote Link to comment Share on other sites More sharing options...
josh817 Posted March 21, 2013 Share Posted March 21, 2013 Get lots of rocker arms and beer. Inebriate yourself so its less painful. One of those Datsun race prep books (the one with the 510 going through a sweeping turn) also elaborates pretty well on how to mess with the rocker ratio. Or just throw a turbo on it and don't tell John/tech inspection. Quote Link to comment Share on other sites More sharing options...
Xnke Posted March 22, 2013 Share Posted March 22, 2013 ugh sorting rockers...I did a whole full five gallon bucket not too long back... Quote Link to comment Share on other sites More sharing options...
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