NOTE: Most of this information is compiled from parts of email messages I receive. If the author objects to this policy, I will re-edit or remove the text to satisfy you. The Bay Area Probe Owners Club recommends safe, legal driving.
3Feb99 The install took about 5 hours, and that included the installation of the purge valve. It's a dry manifold, single fogger, 60 HP shot setup. I don't feel brave enough to try the 70 HP jet. CB is in San Francisco, and I live in Sacramento, so there was about 90 miles of freeway to test things out. I didn't know what to exepct, not having ever driven a NOS'd car before. So I was cruising at about 60 in 4th gear, hit the arm switch, tap the purge switch once, and floored it. Holy shit...I couldn't believe the instant acceleration. It's awesome to say the least.
Once I made it back to Sac, I went Honda/Acura hunting. People like to race all the time around where I live, and they always mess with my Probe. I got on the tail of a 96/97 ?? Prelude, and pulled along side of him. He shook his head, and it was on. Green light, and I pop the clutch and ran almost full throttle til about 6000 RPM's and shifted to 2nd. By this time he had pulled ahead by about a car length. Once I was in 2nd, I floored it and the NOS kicked in like a MF muel !! I hit redline real fast and popped it in third, passed him up like it wasn't nothing. And another Honda bites the dust !!! woohoo (thanks to SG)
3Feb99 Anyone purchasing NOS should know that they changed the valves on the bottle. They now have the Super HI-Flow valve standard. The only bad thing is if you want to attach a blow down tube and blow cap, you have to get an adapter kit. It's part #16166, and it costs $19.95. This is apparently something new that NOS is doing, because Ben at CB Performance didn't know what the hell they were doing with the new valves. He said WTF is this. I guess the kits from a year ago had the valve that you just connect everything on to and you didn't need the adapter kit.
Take it from someone who has installed 3 transmissions in 44,000 miles, do not put nos on your (auto) probe, you will burn up your tranny. It is not built anything like the standards, the autos are ALOT weaker. Talk to any tranny shop that has ever pulled one apart if you don't believe me. The cost to rebuild? 1,800> dollars. It's your call.
Thanks to MF
I am lucky enough to have a nationally ranked professional drag racer in town who also happens to be a NOS supplier and runs a NOS kit on his 8 second street legal Camaro SSZ28. Although he's a diehard pushrod/chevy guy, his advice is free flowing and he seems genuinely interested in my success. His car is in two major magazines this month and he is currently points champion in his division. With that said, I had a long discussion with him a couple of days ago after I showed him one of my "brutalized" plugs. As I purchase nitrous and other "goods" from him, he probably doesn't want to lose me as a customer :-)
Upon glancing over one of the better "brutalized" plugs, he determined as I did, that I needed to make some changes to put it politely. For those just beginning to experience the power of NOS or are considering it, please remember that I am pushing the "ragged tuning edge" as Mr. B--- put it to me. If you're running the standard 36/42 jetting, you needn't be completely passive and never check your plugs, but with basic maintenance and common sense, you won't run into any of the problems I have. I'm trying to push the limit without blowing the motor. I don't want the discussion to break down into a nitrous isn't safe debate....:-)
The main problem has been that I can have five plugs which look just fine (at least they did to me) and one that will have the ground strap partially melted off. I attributed this to distribution problems which Mr. B---- agreed, but there were other problems as well. Small black specks on most of my plugs revealed detonation (even though our engines have knock sensors) with a slight green tinge to the ground strap. Telltale signs. Those little black specs are actually pieces of the piston crown which have broken off. I thought they were specs of carbon. I had been looking for METALLIC flakes, not black ones. I could make three passes and have nice looking plugs, but I could also run on the street, come home, check the plugs, and find two melted straps! So what gives...
Well, I discovered during the BG meet that I had advanced the distributor (to set my base timing) the wrong way. How I did this remains a mystery. I'm fairly competent when it comes to tuning. Ok, having adjusted the timing back down, I thought I was safe. Well, after a weekend of racing in Michigan including some high speed runs with my brother as co-pilot, I discovered a melted strap in cylinder 5, something that has never happened to that cylinder.
So, with all this knowledge, he began explaining to me what I SHOULD be doing all the time to ensure that I am running within a safe range. I already have several things in place which he recommends. Those are a high flow pump, a/f gauge, fuel pressure gauge, and an adjustable fuel pressure regulator. Next, I should do some testing (which I did last night, more later) and lastly, I should micrometer my jets and take specific, detailed notes every time I run.
Testing: I was advised to take a new set of plugs, and make one 1/8 mile pass (shut it down at the 1/8 mile mark at a 1/4 mile strip), pull the plugs and read them. Make sure to write down the bottle pressure at the beginning of the run, and then immediately after the run. Besides bottle pressure, fuel pressure, air temp, humidity level, and if possible, elevation should all be written down and taken into consideration. It just so happens that we had an import event at an 1/8 mile track in Nashville. Perfect. I did as told, recording a sky high 1500psi at the start (due to the hot sun) and an 1100 psi bottle pressure at the end. I almost aborted the run due to the high bottle pressure, but common sense flew south...Anyway, I immediately pulled the plugs, and to my untrained eyes, they looked perfect. I immediately boxed them so that Mr. Bray could examine them tomorrow. Traction was severely lacking on that pass, as I was spraying much nitrous with fuel to match. Fuel pressure ran a consistent 78psi throughout the pass, as I bumped up my base WOT pressure to 47psi earlier. Off the bottle, the extra fuel pressure really picked up the snappiness and overall speed of the car. I was running a 42 nitrous, 36 fuel jet. I swapped in a new set of plugs and made three more runs that night, without any problems.
Returning to Mr. B----'s shop, I handed over the plugs and he showed me what to look for. Basically, the ground strap should be heated 1/2-3/4 of the total length. If you look closely, you can actually see a line where the heating stops. I ran a mixture of 93 and 116 unleaded octane race gas as an extra precaution. Every plug fell into that range, with a slight BLUE tint to the heated portion. A GREEN tint means that it's getting too hot and detonation is occurring. The porcelain was clean, but he couldn't read the inside of the plug as I was using Motorcraft (cheap) plugs which are painted black. So a/f ratio is as of yet to be determined. The A/F gauge read in the 13:1 range through all of the passes. There was no detonation present, and all plugs looked almost identical. He actually said that I was well within my limits, and I could probably spray even more. Seems an 85-95hp shot is not out of the question. So why do I seem to be frying plugs?
I don't normally run racing gas on the street. Also, street confrontations usually take place at higher speeds, where there's a greater gear and aerodynamic load on the engine, which can promote detonation. I tend to do a lot of top end stuff on the highway which could cause the cylinder temps to rise very quickly. It only takes a split second to ruin a plug, and possibly the whole engine. I firmly believe the Walbro pump has saved my butt in more than one situation. Of course I wouldn't be running this jetting without a larger pump....nonetheless, it's still possible to do damage to your engine, even using the recommended 36/42 jetting. I also ran my timing way too high. I should stay right near stock, maybe a degree or two under. The general rule is, take out 2 degrees of timing for every 50 hp OVER a 100 hp shot of NOS. I'm nowhere near that. So what do I do?
I could just back off the NOS jet. Nah, too boring. What I will probably do is go to a 2 heat range cooler plug (NGK ZFR8F-11) just to be safe on pump gas, and run stock plugs with race gas at the strip. A pain in the ass, but going fast has never been as easy as I nor anyone else would like. Like I said, I want to push things a little. The high octane stuff is just a good safety to have. Although I've run into detonation several times (as denoted by the black specs on the porcelain) Mr. Bray is fairly confident that the piston is thick enough (OEM pistons tend to be fairly thick, if not strong) that there isn't much damage, none of which would cause my engine to run "abnormally" or hurt performance in any way. I will be doing a leak down test next week however, just to be sure. What can happen, is that the top ring can start to lift near the gap ever so slightly, causing a loss in cylinder pressure. Hopefully I have not reached this point! So what happened in Michigan that caused me to fry a plug?
Cold air. Yes, that's right, my jetting in Kentucky may be "just right" but the cooler, more dense air of Michigan may have caused a lean condition. Mr. Bray went through six pistons at a drag meet just because a front moved through, dropping barometric pressure and moving in cooler air. He's pushing things pretty hard, but he commented that the "level" he and I are pushing are actually pretty similar. In addition, I made a run all the way up into fifth gear, well under 15 seconds, but still able to create a high thermal condition in one of the cylinders.
So what should we all be doing? Get VERY scientific and thorough about it. I mentioned a micrometer before...buy or borrow a micrometer and measure the inside diameter of ALL your jets...just because it says .46 on the outside, doesn't mean that it actually measures at .46. Chances are, says Mr. B---- that you could pull five jets out of the box, all with .46 on them and each would be different. Without knowing the exact inside diameter (orifice size) you can't properly tune the vehicle. You may think that a drop down to a .36 jet will give you the proper a/f mix, but that jet you buy may not be a .36. So measure it! Better safe than sorry. Mr. B---- made an interesting comment. A .2 second drop in your 1/4 mile time may "only" cost you an engine...Is it worth it?
So I'll be making an additional test run or two on Saturday, possibly a full 1/4 mile pass just to make sure things aren't changing at the far end of the track, which is unlikely. I'll test with the colder plugs as well, on pump gas to see how it works. From there, another test run on race gas, with the timing bumped slightly I should have an a/f reading using the NGK's and I'll be able to adjust my base pressure up or down accordingly. As stated earlier, a simple drop in temperature can change things very quickly. So if you really want to push things, be careful and do plenty of testing! The satisfaction of blowing by that 98' F-Body can be short lived if you discover on Monday that you've damaged a piston. I feel confident that I have the proper items in place to run .3-.5 seconds quicker. I am avidly persuing larger injectors for the added safety factor and increased power potential as well.
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