well it's been way to long since i have posted or added to a topic .but as we all know sometimes things don't always bounce in your favor, and on that note i'm glad 2007 is almost over and am looking very forward to a great 2008 !! both personaly and nitrous wise.
one thing i have been doing is rereading old topics on this site and i can not tell you how much great information has been posted that i have missed, and i would recomend others to reread old topics and pic out the small details.
this year i was very limited to the amount of time i could spend on performance , but i did manage to make some progress when i had a few moments.
-with all my new knowledge based from the lessons learned at the track i did get my engine and trans modifications done that i wanted.
-5th gear in trans dropped to a 1.09 ratio
-new nitrous based camshaft
-switch of rings to a different setup.
-new breather system-
-new cylinder heads with larger valves and flow.
-new distributer.
-car was setup and broken in and i must admit drove great on the street .head and oil temp's were great and the car proved to be very streetable.all carb jetting was completed and ignition timing was worked out.final a/f ratio wide open was 12.6 :1 and total advance was set at 28deg.
with a vw event in mid august as my fantasy target ,i set my sites on racing for the first time but was doubtfull i would make it.
10.00 am that friday morning i could not believe it but i was actual driving my car into the trailer and was actually going racing,of course i was not prepared and seamed to have forgotten about my to do first list !!!.
got to the track late but was just glad to be there.
-at the track i actual finnished the replacement of the nitrous supply lines from AN-4 to wizard 5mm pipe removed my new max extreme and reconected my maximiser .go with what you know i thought and set everthing the same.
-first run with 50 jetting installed i hit the bottle in 3rd and 4th and netted a 12.4 at ? mph .was more worried about making it down the track in a untested car than speed.back at the pits i downloaded the data and i was pig rich when on nitrous 9.1:1.there was only time for one run left maybe two if i was lucky.
so i installed the 4@40 fuel jets and the 2@100 nitrous jets .dropped fuel pressure to 6 psi and upped the bottle pressure to 1100 psi.
car ran well but not great .
ran a 11.6 at 115 mph ,not bad considering when i check the lm1 data i was running at 9.6 :1 a/f ratio.
that was it for racing .the year before the best i ran on the same jetting was a 11.8 at 114 so there was a upswing and would assume it would run a bit better when i got the a/f ratio worked out.
back at home it was now nitrous setup time.kowing the N/A a/f ratio was set , it was time to get back to basics and start with the wizard static test .when in doubt start fresh.and remeber the staisc test sets the nitrous A/F ratio.
replaceing the jets with 4@10 fuel and 2@25 nitrous (25 h.p test) ,1000 psi bottle pressure with a full 10lb bottle ,fuel pressure at 7.5 psi i performed the static test .
-as with static tests the year before my motor would not rev past 4200 rpm ,and was reading very rich in the 9's so i dumped the pressure down to 5.5 psi and this time reved to 4400 rpm and reached 9.7:1 a/f ratio.at this point i figuring that its possible that the 25 shot is just to small for my motor . i replaced the fuel jets to 4@20 and the nitrous to 2@50 (50 h.p jetting) and upped the fuel pressure to 7.5 psi .during this static test car reved to about 4300 rpm and again ran a low 9 a/f ratio,again dumped fuel pressure down to 6 psi and during the static test reved to 4600 rpm and a 9.7:1 a/f ratio.
so with limited jets in hand i installed 4@10 fuel and 2@50 nitrous and upped the fuel pressure to 8.5 psi ,bottle pressure still at 1000 psi results were 4900 rpm at 10.2:1 a/f ratio!!! better i thought ,dropped fuel pressure to 7.5 psi and retested .rpm hit 5300 rpm and 11:1 a/f ratio.so with a bit of math
set the fuel pressure at 8 psi and as expected ran a 10.6:1 a/f ratio. (should of clued into the not reaching higher static test rpm at this point) had to leave it like that and hope for more time to come along . well it didn't but, i found myself heading out to the last evening drag in october .
with the 50 shot still installed and expecting to do well as i figured my nitrous jetting was worked out i gave it all she had down the track ,results were 12.301 at 109.?? mph ,back at the pits i could not believe it my A/F ratio on nitrous was 13.2:1 !!!
it was all making sence now,not even going to tell you what happened on my second pass as we all know what to much h.p and a damp track running on slicks will result in .
so were am i at, or should i say what i've figured out.
---due to the nitrous and fuel pipe layout on my motor ,during a static test i will have to say very little nitrous/fuel mixture is getting past my throttle blades and into my motor actual it just bounces of the throttle blades and back out the carbs, because of this the motor is unable to rev up and give acurate a/f ratios during the staic test . actual full throttle tests need to be performed to setup my jetting,makes sence that the jet ratio will be 4@15 fuel and 2@50 nitrous as the 10's were to lean and the 20's to rich.
--also a/fratios are effected by my exhaust ,i have 3 different setups.1st a normal muffler set up 2nd a open megaphone and last a baffled race bullet .i came across this by luck during idle tests and street acceleration tests .depending on which exhaust tip i use there is a big difference on a/f ratios .
so the lm1 data needs to be used as a guide with the plugs being used to validate the final mixture . eg , the open megaphone shows a leaner mixture than the others so just because it says its 10.7:1 it may be leaner than thought.
--also will move my fuel pipes to the short side of the manifold (top) to help prevent the fuel puddling along the bottom of the manifold .
i'm almost sold that the final piece of the performance puzzle will be better atomisation of my fuel ,either by pipe placement or shape as well as increased fuel pressure.
sorry for the long chopped up post but it's good to be back!!!
trev/anthony will call you this week
jim
