Phyte Posted April 16, 2004 Share Posted April 16, 2004 I'm going to start rebuilding my L28et in a few weeks and its got a BHG. I'm going to be running 9-10 psi for quite sometime, then up the boost down the road after interior/paint(year or two). I like to save money where ever I can, so if a stock HG will work just fine for this application I'd rather use one of those instead of spending $150 more on a steel one. Phyte Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 16, 2004 Share Posted April 16, 2004 It depends. If you are going to be running 10psi non intercooled the stock HG will hold.. but it does not take much leaning out to blow. From what I understand the stock Nissan headgaskets are good for upwards to around 16psi as long as you have enought fuel and the IC to not run lean and ping.. Quote Link to comment Share on other sites More sharing options...
Phyte Posted April 16, 2004 Author Share Posted April 16, 2004 It won't be intercooled just yet. Now the obvious question, where is the cheapest place to buy a nissan gasket? Courtesy Nissan in richmond TX? Also I'm running a larger pump and larger lines. I'm making a fuel rail too, but the injectors will be stock. Thanks Quote Link to comment Share on other sites More sharing options...
Phyte Posted April 16, 2004 Author Share Posted April 16, 2004 Autozone lists Felpro, Beck/Arnley, and ROL on their website for head gaskets. Are any of these better/worse quality then the nissan? Phyte Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 16, 2004 Share Posted April 16, 2004 The best stock style gasket is the Nissan, so if you are going that route, spend the extra $$ and get the Nissan one. A freind runs them exclusively on his GT2 L28 race motor (~14:1CR), without problems. Pete Quote Link to comment Share on other sites More sharing options...
Phyte Posted April 16, 2004 Author Share Posted April 16, 2004 I just got a quote from Courtsey of $49.05 + 8$ shipping. I'll spend the extra money over the $17 felpro cause replacing HG's are kind of a pain, specially for only $33 difference. Phyte Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 16, 2004 Share Posted April 16, 2004 I dont think its the head gasket that goes wrong just from boost, its state of tune. Ive run 10-15psi for a year now on a fel pro, and Im in boost alot Quote Link to comment Share on other sites More sharing options...
Afshin Posted April 16, 2004 Share Posted April 16, 2004 I would go with the nissan HG, $33 is cheap insurance. Sure the fel pro may do and many have had them work well, but too many of them have failed in my opinion to ever recommend them. Spend the extra $33 and you will be less likely to have a HG failure. I think better parts (within reason) save you money in the long run. Quote Link to comment Share on other sites More sharing options...
Garrett76Zt Posted April 16, 2004 Share Posted April 16, 2004 My ORIGINAL stock headgasket didn't blow until I gave it 18psi and the car was running extremely lean. If the car had been tuned properly I think it would have held just fine. Got mine from courtesy nissan, they were not as knowledgeable as I was expecting but there prices are good. Garrett Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 16, 2004 Share Posted April 16, 2004 I can understand Courtesy not wanting to share too much info, makes them more liable I guess. 33.00 is cheap insurance and well worth it. I bought a fel pro kit for my engine a while back and just used what came in the kit, I would use fel pro again because I am having a good experience with it, but I will need head studs Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted April 16, 2004 Share Posted April 16, 2004 Don't mean to thread jack, but I'm going to be installing my i/c this summer since I have my summer intern job lined up. Even with 91 piss gas and ~15 psi the stock HG is good as long as I don't ping? I'm only asking because as far as I know, I still have the old 22 year old HG sealing my motor. I've never messed with an HG before so I'm kinda hoping I don't have to take the head apart. lol John 82ZXT Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 16, 2004 Share Posted April 16, 2004 When you turn up the boost, 5#it happens sometimes. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted April 16, 2004 Share Posted April 16, 2004 Felpro's are fine. A lot of people run them at high power levels w/o problems. But a few guys have had problems with them as well. Stock is better, but then again I've heard people that say they've had nothing but bad experiences with them as well. I was running 10psi w/o an intercooler for a few months, on a Roc gasket (Napa brand). It eventually went out, though there were some 'clues' suggesting it had nothing to do with running too much boost or any detonation or anything like that, rather, the gasket looks like it wasn't lined up right, and I later found out that one of the head alignment dowels were missing, which was probably the cause of that. I never heard any detonation running 10psi w/o the I/C, and even on the dyno, revved up to 5500rpm, there was no audible detonation nor was there any sign of detonation on the dyno graph (which usually shows up as a very erratic hp curve where it starts to occur) though I was DEFINATELY running too lean to be considered safe after 5000rpm, at about 13:1. I am now pretty certain that you are simply not safe running 10psi with ANY gasket, unless you are somehow providing extra fuel on the top end. The stock EFI, without exception, will simply NOT supply enough fuel above 5000rpm to support 10psi of boost. Even with the I/C (probably moreso with the I/C since colder air is denser = extra oxygen). I've seen quite a few dyno runs by other guys that show the same thing. If you can excersise enough self control to keep it below 5000rpm no matter what, then you'd probably be okay. Otherwise, keep it to 9psi. I'm running 9psi on a stock nissan gasket now, still with no I/C, so far so good. As soon as I get some extra fuel I'll bump the boost back up to 10psi, and then when I get my I/C installed I'll aim for 13, stock gasket should be fine. I'm hoping to install an adjustable FPR soon and up the pressure by enough to get the top end air/fuel ratio to about 12:1, and then tune out the extra richness in the midrange by adjusting the AFM. Total investment = $60 + dyno tune. Quote Link to comment Share on other sites More sharing options...
Phyte Posted April 16, 2004 Author Share Posted April 16, 2004 So with me upgrading the fuel pump and larger lines, with a custom fuel rail should I be ok on the fuel issue above 5000rpm, or is it an injector issue? Also by modifying the AFM, do you mean tightening the spring? I'll be putting an adjustable FPR on my new setup and I'll go ahead and tap a pressure gauge on the rail. Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 17, 2004 Share Posted April 17, 2004 Im running a felpro headgasket, im on my second one. Havent had any trouble out of it. I was running 14psi with bad tuning my first go around. The #1 piston ringlands went out before the headgasket. So when i broke the engine down i went with another felpro. Well see if it can take 18 psi pretty soon, i dont have any doubts, well....i am an optimistic person. Im also running stock headbolts. I havent heard anything bad about them. 33 bucks? Eh its up to you. I'd say the money is better put towards studs. Course theres always HKS.... -Austin Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted April 17, 2004 Share Posted April 17, 2004 So with me upgrading the fuel pump and larger lines, with a custom fuel rail should I be ok on the fuel issue above 5000rpm, or is it an injector issue? Also by modifying the AFM, do you mean tightening the spring? I'll be putting an adjustable FPR on my new setup and I'll go ahead and tap a pressure gauge on the rail. i've already upgraded my fuel pump, as well as running larger lines. Fuel pressure is a little above stock. Fuel rail should make absolutely no difference. Don't think it's a problem with the injectors themselves, I know people have gotten more power than I do out of them. Rather, it is a limitation of the stock ECU and AFM. Figure, the stock ECU is a actually a very limited piece, not very flexible on it's own, and programmed to only handle the stock cars 6-7psi of boost. Now, I also figure that at most, it's programmed to safely handle up to about 9psi, as this is where the factory pop off valve is set to blow, so it makes sense that Nissan thought to make the EFI at least safe up to that point. Now, the ECU uses the AFM to measure actual airflow. Problem is, the AFM's flap is at it's maximum open condition, at WOT, WAY short of the engines 6500rpm redline. Accurate guesses put it's measurement limit at around 4000 or 5000rpm. Makes sense to me as every dyno I've seen, including my own, seems to hold good air/fuel ratio at boost levels even higher than 10psi (usually running quite rich, actually), up to about that rpm. After that, the ECU, not having a way to accurately measure airflow anymore, resorts back to it's preset fuel maps, using only intake air temp, coolant or head temp, and RPM to calculate how much fuel to throw in there. As boost is raised above the 6-9psi that the ECU was programmed to see, it will no longer try to compensate for the extra air present. I'm not sure how much extra fuel pressure you might need to bring the air/fuel ratio back down to acceptable levels... probably not enough to make a huge difference or to really increase the boost cieling much. But I figure it should be enough to run 10psi safely. And yeah I was talking about tightening the AFM spring to adjust it. I'm hoping that a good balance and decent tune-ability can be achieved with this type of setup and tuning. Adj. FPR to richen up the whole rev range, then adjust the AFM to lean out part throttle, and WOT range up to 5000rpm. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted April 17, 2004 Share Posted April 17, 2004 Well - with ARP studs, the felpro gasket will hold up past 25psi - with no pinging. My stock bottom end went there a number of times when I first got my T3/T04E. I had a wastegate problem and massive boost creep. But - I have SDS and 550 cc injectors = lots of fuel. Keep it from pinging and you'll be fine. Doug Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 17, 2004 Share Posted April 17, 2004 I dont think its the head gasket that goes wrong just from boost, its state of tune. Ive run 10-15psi for a year now on a fel pro, and Im in boost alot DING, DING, DING. Give this man a dollar. It is not boost that does damage, it is detonation. That is why there is no magic answer to the question "how much boost can I run?", even with the stock stuff. You are playing craps when you start "fiddling" with the AFM, can you get 94 octane or are you limited to 91, how much "green stuff" do you have growing on your fuel pump electrical connections, do you have a huge vaccum leak that sucks in air AFTER the AFM leaning out the engine, how are those 23-yr old stock injs holding up? I have seen 22psi with stock head gaskets and the non-turbo ring lands let go before the HGs. The magic answer I would say is as much boost as you can until you reach the point of detonation, then back off a tad. How much boost that actually is depends on how the above gets answered and as FL327 pointed, how well your setup is tuned? Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted April 19, 2004 Share Posted April 19, 2004 how much "green stuff" do you have growing on your fuel pump electrical connections great memories huh Scottie tbs Quote Link to comment Share on other sites More sharing options...
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