clint78z

$600 that's what he told his wife !! LOL

Awsome times Zfan many people don't realize how fast that is until they try an keep up themselves. Breaking 3 takes some serious talent, sounds like you were close. I was fortunate to run a 10k and see a 29min pass me on the way by. I am fortunate to be a part of a wonderful running community, lot's of cyclists around too. Went for my very first ride in a pack last night, it is quite fun. Several of them were training for Ironman, I didn't get dropped. It's never too late to start anything in life, I plan to be that crazy old bastard racing all the young pups.

My Zed has taken the back seat to my other passion running. I know there are some runners here and they know what I am talking about what kind of accomplishment this is. I ran a very consistent 3:47 marathon with some hills to boot. I was in the zone and probably could have done a 3:40 if I pushed it a little more. The 2 km's were a little tight in the hamstrings, but ran through it. I have my sites set on Boston in a couple of years !! For those of you that don't know, Boston is the superbowl of running. I am not your typical distance runner weighing in at a lean 190lbs. http://pg.photos.yahoo.com/ph/clint78z/album?.dir=c869&.src=ph&store=&prodid=&.done=http%3a//photos.yahoo.com/ph//my_photos

I ran across this article while reasearching combustion data for work. Thought it might give some engineer types a good read. http://www.loetdesignz.com/Engine%20Analysis.pdf#search='combustion%20efficiency%20EQUATION'

I own an Lm-1 and have been fairly pleased with it, you may note a lot of people tend to get bothered when they see a jittery A/F on there tuned car. Most often they blame the unit itself. The resolution on the LM-1 is very fine, this tends to show you the swings in data that you would not see if you didn't have that resolution. I am going to say which one is right or not but I will give you some inside info from myself who works with these type of machines. For example if someone analysed your running form, it looks pretty smooth. If you used a high speed camera, then all of a sudden you can see so many nasty things you can see is wrong. Some you can correct and some you can't. I have dealt with gas analysers at my company for quite a while. They are very touchy units !! The units O2 cells must be calibrated once a year, after that they become inaccurate. With this proceedure they hook it up to a calibrated gas and compare the readings of the O2 cell. Another thing that can screw up readings on a dyno is the desacent. This drys out the gas before it is measured. I would error on the cautious side, an EGT can help a bit too !! I would concentate of keeping the A/F smooth, rather than picking an exact number.

Good point JohnC, air always likes to move in the direction of lowest pressure. On most cars there is a small amount of valve overlap, very small. On the exhaust stoke the piston is pushing up the exhaust valve is open, it begins to close as the piston reaches TDC. Before the valve is almost closed the intake begins to open. Because the exhaust gas is rushing out the port it creates a venturi effect and pulls in intake air (scaveging. If you have too much valve overlap or high duration cam, you basically start too early for the effect to happen and the exhaust goes into the intake and dilutes it. (Exhaust Reversion) I usually don't like the term backpressure for the exhaust, pressure drop between two points is a little more accurate. That's splitting hairs. Cool thread, let's keep it rolling !!

Not too sure the bolts are up for the job of keeping the head from warping when it heat cycles. Aluminum grows quite a bit when heated. Must aplaud on ambition to try new things, it may not work the first try but keep at it. My suggestion to keep the head together and make it fairly easy to put together. Is to make a cradle to support the head in. Slip each section into the heated cradle, and allow to cool creating an interferance fit, weld it in to prevent twisting forces. On the chamber side v groove the deck and weld between sections. The cradle should be made from same material as the head so it expands at the same rate. Just an idea to a difficult problem !!

Perhaps TimZ can chime in with some numbers he was seeing preturbo in the exhaust manifold. I think he did some testing to size his exhaust turbine. The pressure seen can help you size the A/R ratio on the housing. This can tell you if your housing is restricting the flow on the top end. It is not a good idea to put a restriction in a system for the sake of getting a certain pressure number. The only benifit you get from that is lowering the noise, that can eb done other ways. A restriction is just that it restricts the flow of exhaust gases. Then engine wastes more power trying to pump the exhaust gas out, instead of turning your wheels. It is more important to focus on gas velocity and scaveging effect, tuning for a rev range.

These designs can easily be tested, a simple pressure tap at turbine outlet and where the DP joins to exhaust. Use copper line to wick heat away and attach to your boost guage with a slip on end. In the end nothing beats real world testing !!! It's good to see everyone is trying to optimize a great design. The huge difference will be going from stock to a mandrel bent aftermarket downpipe. You will gain better spoolup and maximum horsepower, it's win/win. Keep up the great works guys !!

As for the actual A/F ratio used if it is 12.5 or 12.8 there will be little difference. What you want to work on is keeping a smooth transition of fuel cell to cell in the fuel map. TPS enrichment and delta map enrichment are quite important for a street car. The big secret in L6 is getting some good timing dialed in just off idle, if you make too big of jump well it will break up, but if you get it right it has awsome throttle response and pull real hard out of the hole. There is a drastic difference in spoolup time to be found if you spend some time working on these cells individually. You have to tweak get one cell close then go back and massage fuel table and enrichments. 1. Dial fuel table close 2. Start bumping a small area in igntion table up by one degree. Drive around in those cells, and note if it is worse or better. 3. Go back to the fuel table, it will be easier tweak the fuel map again now that it is running stronger. Repeat many times. I typically tune the deltaTPS enrichment in lower gears since it takes more TPS to accelrate the car. Repeated runs using lot's of throttle at low rpms will show you what is better and what is not. For deltaMap enrichment tune at highway speed in top gear low rpms, this will blend in the transition between cells in the main fuel map. This is general to most efi system, but should get you in the right direction. Datalogging can be a great feature. Spending time and making small changes tweaking is the way to zone in on a perfect tune. Happy tuning !!

I live in the bald *** prairies, luckily our city has some nice trails for run and mountain biking. I get bucked off but not that far to fall. After I get my house construction done I am going to start planning to do my first IronMan. The only carbon fiber thing I own is a road bike. Hopefulley that doesn't send me home with my tail between my legs. It's funny I explain some of the stuff I do to people and they look at me like I am crazy, that's only partially true. Some people ask how can you do that, I reply how can you sit on the couch all day. Every person has there thing, just want to enjoy it as much as I can. Tree climbing sounds pretty cool, unless an attack squirrel is after you.

Should have known Mikelly's new nickname should be Been der don that !! Good to see you live such a diverse life, I also like trying as much as I can. Nothing beats the view when getting a good outdoor workout. I am trying to be a little more cautious, I practice falling from the wall. Last thing I want to do is wreck anything that takes away from running. Sorry to hear about the fall, that's a nasty spill. I would say you came out pretty lucky from that one. Mikelly have you tried using glucosamine for joints, not a miracle cure but does help. A good massage therapist can get rid of alot of scar tissue, and restore blood flow and mobility to many areas. Your body is just like a car and needs to be worked on and tuned up. I am sure there are still a few good miles left in ya !!

It's definately worth a go if you are thinking of trying it. It's funny because it's usually the more muscular type of guys that fade the first. My brother and I were weight lifting partners, after 2 hours we were done like dinner. I guess you can only pull yourself up with one arm so many times. The girls climb just as well, but use more feet and finess. I just found this page, explains some of the many moves. http://www.webdimension.net/xzone/xclimb/climb.htm

Thanx I did a search before, that is a good starter one. I was looking for more of the practice and drill movements. They have about a thousands different techniques like drop knee, flagging, finger jamb, dyno... the list goes on. It looks so basic, but it is such a creative sport. Some of them can be a bit tricky to figure out what they are talking about. It's a completely different language. Ordered up some new shoes last week, rental shoes don't have the soft rubber to stick to the wall.

I have started wall climbing just lately, and really like it. I stay in fairly good shape running marathons and I am no slouch in the weight room. The amount of finger strength of some of the top people are amazing. I am slowly learning technique over brute force. There are so many ways people tackle the same route. I am practicing my footwork, and was wondering if there are any good websites with diagrams of some of the more basic moves. Can't wait to take a climbing vacation, probably hit Squamish BC.

Nice exhaust system JohnC, I bet it sounds as good as it looks. You will notice the flare ends are opposite to exhaust flow, this provides way better sealing than the donuts. That's a pretty slick trick with the cones, I would have missed that one. Haven't dealt too much with 2 strokes, I would imagine why the are so sensitive to exhaust tyuning is because they have twice the amount of exhaust pulses as the 4 stroke. Perhaps someone can chime in on the expansion chamber. Did anyone see TRUCKS show, the project copper head had a 572 with electric cutouts. Sounded quite nasty indeed. There was a big worm drive that opened and closed them. So who here has used header wrap?? Any comments on this from N/A or turbo guys. I have heard on most street manifolds, it can collect moisture and create rust. It can also overheat cast iron, when that happens it lower the strength of it. This can lead to cracking, and failure. I have heard of good things about cermic coatings on pistons and inside headers as well.

I found a cool link to a fairlady Z, 432R video it's pretty decent shots of it !! http://www.teccom.jp/images/video/bm_fairlady001.wmv

By the sounds of things you should not be getting detonation with adequate fuel and conservative spark. Mine is the lower 7.4 CR, but I don't think it would make that much difference. Perhaps you have a cylinder that is running lean, and you are making the other cylinders run richer to make up the total AFR ratio correct?? A somewhat crude test can be done by pulling the injector wire on each cylinder while idling and noting the rpm drop. It will give you a bit of an idea if all are balanced or not. Wideband is useful, however nothing beats good tuning practices and there is ton's of hidden power and drivabilty in the spark map. Probably the most overlooked area IMHO

Initial timing is 20 deg BTDC, max advance is 40 deg at 3000rpm during cruising. I get pretty good gas mileage with my DFI compared to the ole L jet. Typically I use 87 octane when boosting 7psi, and 91 when going to 12psi. I have alot more playing to do before I turn up the wick to 17 psi. The stock clutch would puke on me !! Did you change your cam over to a turbo one, they have lower overlap to reduce exhaust reversion from high pressure due to the turbine. My self i am getting an oscilloscope, help diagnose problems on other cars and my own when they happen.

You can probably be more aggressive with timing. Many people get hung up on running a certain psi boost. When they could back off the boost a tad and run more timing to produce more power. You are running a higher compression head correct ?? I would start sneaking in a little more timing in the lower map and work your way up gradually. I think 24 degrees is what I run.

Did you get yours to idle at 14.7:1, my idle was about 14:1. I go from idle all the way over up the rpm line with 14.7. I use a bit of extra gas to transition off idle cell. I think you can go leaner at part throttle. I would Transition from 0.8 bar of 13.2:1 and be 12.7:1 by 1.2bar. 12.5:1 by 1.5bar. Sounds like you could do a little more tweaking while driving on the highway, turn your O2 correction off !! Tweak the fuel map under steady load, tweak the igntion at that point, then set the accelation enrichment so it doesn't stumble. Do the whole map like this, then repeat again. Drastic timing changes can make the car jerky, I have problems tuning very light throttle.

Hey Drax thanks for the tidbit on second and third pulse, it makes sense that would happen but something I have never thought about. So how can a person go about designing their own exhaust system without doing a ton of hit and miss calculations ?? Keeping a smooth path, smooth welds reduce turbulence and resonance. Try to avoid transitioning from different pipe sizes. The exit on the pipe should be a bellmouth to avoid exit loss. Mandrel bent is a good option, if your going to make a turn the less the angle and longer the radius the better. Crush bent is definately out, it's noisier and robs power.

Yes I did leave a little out, I did that so the main point I was trying to get across was not lost. Yes I was hoping to spark even more disscusion from all the talented fabricators, engineers, and tuners on this board. Thanks for the great discussion. It's already heating up. I guess I will start in order here with johnc, I was talking of the flow restrictions of just the elbows not the entire system being 3 times. Sorry to muddy the water on that one. I used a fluids chart nomograph to roughly compare the two long radius elbows. The 2 1/2" 45 degree has an equivalent length of pipe of 3 feet of pipe, the 3" 90 degree has an equivalent length of 10 feet of pipe. More than likely there would mabey be a 0.5psi difference. I was thinking about on a 280zxt turbo, lot's of people want that 3" downpipe on their car and have to use two 3" 90 degreee bends. When more than likely the better performance would be gained by using two 45 degree 2 1/2"bends like ScottyGNZ used to make. You are wonderfully right in stating air hates to turn directions. My point was that just because you have a big fart pipe on the car doesn't make it fast, it has to be designed correctly. JohnC you are correct again that on 1 liter Suzuki, no difference would be made between the 3" and the 2 1/2" system. It simply does not flow enough air to make any change. It would have something sized to keep the velocity of gases moving out of the cylinders. Drax yes I was talking about multi cylinder engines, the pulses from each cylinder can produce a scavenge effect. I didn't say predicting these principle were easy, thermodymics is a beast I deal with every day. I know a fair bit about this stuff, but can be wrong about certain things and though it would be fun to discuss. Hey you never know when you can learn something. Too bad it's not as often as we forget things

Thought I would start a thread on the science of exhaust systems, and try an take away some of the mystery behind the subject. Basically when you look at an engine it is an air pump. Fluid dynamics and thermodynamics can be used to understand what is goin on. First off I would like to make the statement of people using horsepower and torque as two different entities. HP is just a math number that is made up of torque at a certain rpm. I will start with the combustion chamber and go from there, the exhaust gas hot (600f-1800f)and is waiting to get out of the chamber. It has lot's of volume the higher temp or engine load you get. As the cam opens the valve it has a certain speed as it exits through the port it as a pulse into a manifold. What we try to do is tune the pulses so they fall one behind the other. This creates a scavenging effect and actually sucks the gases out of the chambers. This tuning usually happens at certain load on the engine (a sweet spot if you will). It collects to a main pipe of given diameter 2-3" usually. The exhuast gases cool as the reach the muffler the velocity goes down. Things to note, and exhaust system is a package and all components must be designed to work together to optimize performance for a given powerband. Another common thing I hear is "Backpressure creates more torque" This is not directly true, and I will explain why. Backpressure due to friction loss is an evil thing, and will always steal the amount of power and engine can make. It is true that a 2.5" exhaust will usually create a bigger torque number at a lower rpm than a 3". It is not the backpressure which gives you the more torque it is the velocity of the gas at that rpm that gives you the bigger number. So for designing an exhaust system you must take into account the powerband of the motor you want to use. The camshaft you are using, size of motor, head design. Fortunately the legwork has been done by most other people. Things to note spend more time at the manifold side, making sure exhaust flow has a smooth path of flow. Since gas is so hot this is where major restrictions can happen. For example if you can use two 2.5" 45 elbow or two 3" 90degree elbows which one would have less restristion ?? The answer is the two 2.5" 45 elbow has 3 time less restriction than the two 3" 90's. It might be neat if some of us took a typical 6 cylinder and a 350 chev and did some of the calculations on this.

Do you have the old 280zx turbo laying around?? If so simply swap the exhaust turbine housing. You will have to change the wastgate controller from the other one too.