jeffp

I have the adjustable Tokico's on the rear of my car. The difference is night and day. I DONT want the car squatting that much onder power. In fact, use the stock setup, get on some wet pavement and nail it and see what happens. You WILL get wheel hop! I had to set the adjusters to the 5 position to square the car away, in fact from the 3 position to the 5 position is night and day according to Clark at JWT when he was doing runs with the car tuning it. I had them set to 3 and he commented about the traction and handleing, so I set them up and it was a different car all together. The car still squats somewhat, but it is not unbearable and does help somewhat. I have KYB non adjustables on the front of the car, they give me stability, but they still allow the front of the car to lift and set on the rear tires. Good enough for me. I cant do the clutch it, nail it, and let the clutch out deal, as the tires just break lose. But I figure with a good set of wrinkle wall 8.5's that should not be a problem either. And YES, I can run 8.5's on the rear of the car without flares with the wheel I have selected for the car centerlind convo pro's with a 5" back space will do the job, you have about 1/4" of space from the wheel to the control arm with that combo, and look at all that space in the wheel well for tire growth. Anything bigger will require flares, but I dont see that as being necessary at this point.

>You cant put it any better then that, the outlet on the T3 is 2.25 inches I believe if I remember correctly, so what would the 3 straight off really help, I think I would go with the 2.5 dp and then go to 3 and leave it at that.< That statement is true, but not entirely true. I have run the stock exhaust turbine housing for two of my builds. The stock housing is in fact 2 1/4" however, the housing, and the waste gate flapper and outlet(the part the bolts to the housing) can and SHOULD be machined out to 2 1/2" and a stage 5 wheel run to get to the higher hp output levels. That is minimum! I have tested the system back pressure with the 2 1/2" turbine housing, and my downpipe that starts at 2 1/2" ID and transitions to a 3" ID in about a 1/2" flare. My testing of the system yielded me exceptional results. @ 25psi of boost, I was getting 25psi or 24psi of back pressure @ the turbo inlet, the system NEVER reached the cross over point and my test was made @ 7K rpm's. To my knowledge, no one has ever done that test of a system. I did not waste my time with a 2 1/2" system, I was interested in getting the best results the first time so that is what I did. Now I am running a GT35 Garret and the exhaust turbine housing is perfect! the wheel is 68mm and the housing transitions to 3" @ the outlet of the housing. I reconfigured the DP to fit a quick disconnect and now the sytem is 3" all the way through. It took about 3 years for Garret to catch up with what I was doing with their old turbo's and, I also have two housings a .63 A/R and the standard .82 A/R turbine housing. The .63 housing was not available at the time I bought the turbo, and when I found out about the production of the .63 housing I got it, for about another 450.00 the turbo got expensive, but I now have all the options I want and need to optimize the turbo, and my 3" system. The parts are out there, but you are not going to get it for the standard 700-800 dollars like many want. But, when you go from zero boost to full boost @ 3K rpms, in the blink of an eye, all the way to redline, it sure makes it worth the time and trouble.

I have seen a number of BOV's and there are a few out there that vent to atomsphere. I dont think that is a good way to do it myself. You get problems like backfiring and problems associated with incorrect fuel mixtures. The way that has always worked very well for me is recirculated. I have never had any of those problems with that configuration. True you dont get that cool pisst sound, but what are you going for, bling bling, or function?

About the dyno charts posted on Jeffp's site, one thing I wonder about, is if that '100% bone stock 280zxt' had an aftermarket boost gauge or if they were even watching what the boost was doing. It's pretty common knowledge that freeing up the exhaust by a significant amount will result in an increase in boost, w/o changing the wastegate setting or boost controller setting. I"m thinking this probably accounts for part of why in that particular case he gained such a big improvement in power and torque. Of course the bigger exhaust made a difference, I'm not doubting that, just thinking it didn't make ALL of the difference. The test was completed on a BONE STOCK 280zxt. The only thing that was changed from stock was the exhaust. The waste gate actuator was stock, everything stock. Now that I have cleared that up. The waste gate is operated by the pressure developed by the compressor side of the turbo. The exhaust turbine side has nothing to do with when the waste gate opens. It gets 7psi and it opens, regardless of what the exhaust side is doing. the two do run hand in hand when you get to the point that the back pressure on the EXHAUST turbine/exhaust reaches a point that the restriction in flow basically is a plug to the engine breathing, when you reach the "CROSS OVER POINT" you are done, unless you can develop more boost to have a higher level of pressure then the exhaust side, the air/exhaust will follow the path of least resistance. The waste gate, will operate @ 7psi and open under any condition, it sees 7psi on the gate it opens, now wether it acts like a added exhaust dump or becomes part of the exhaust system to relieve back pressure, and that does happen, it will STILL open @ 7 psi. Have you ever driven a restricted turbo car? you get to a point that the engine is at its max boost, and rpm, and even if you still have throttle left on the accellerator the engine doesn't go any faster, no additional torque. The engine is choked and can not pump additional air through the pump(or engine). When the exhaust system is restricted and reaches its point of saturation (meaning the exhaust side and intake side pressures are equil) the pump will not produce anymore power. Now keep in mind the combustion pressures and that to also aids in the flow out the exhaust as it creates an increased pressure differential on the exhaust side ONLY, that is why some say you can go X amount over the intake pressure and the pump (or engine)will still work. Now create an exhaust side that is far less restriction then the intake side. What do you get, correct a significant increase in flow, and less restriction, so the pump in effect now is limited by the intake of the air and not restricted by the exhaust back pressure. So your waste gate STILL opens at 7 psi, but the energy expended by the pump to move the air through the system is far less, so you pick up additional working power that was before used to operate the pumping function of the pump(or engine). What you have done in effect is to move the energy produced by the pump from the energy required to operate the pump to energy that is now freed up to make the pump produce more power for the same expended amount of energy. Does that make since?

You are correct, the engine runs stronger when it is cold. All of the active components are cool and the intake air is cooler. You want a fix, do what BMW has done with their engines, go with a carbon fiber/plastic comp intake and you will get overall better performance when the engine is hot. Same thing as running on a nice 50 degree day as compared to a 90 degree day. The air is colder,denser and the engine runs better/stronger provided you can provide the additional fuel for the burn.

Hi Dan, well yes I do have one of those tensioners. I like the design, I have looked over the method and spacing of the idlers, which had had a mod done to them to move the top idler/adjuster down about an inch. I am going to run it on the car myself. I NEVER liked the stock tensioner on the engine, and I am sure my cam timing was changing. The assembly, when installed on the engine tensiones the chain perfectly, and the thing I was really impressed with was the fact that I could push the tensioner tight with my finger, the chain was tight everywhere, but not to tight if you know what I mean. Then I turned the crank with an indicator on the cam lobe, and there is no slack, play in the cam operation. The cam moved exactly with the crank, I couldn't even get it to lag the crank by one degree. That is good enough for me.

Lets look at the chain and gear(sprocket) first. The roller chain and sprocket configuration, although very srtong, promotes and instable operation pretaining to relative contact area of the chain to sprocket area. The chain, as drag, torque, and speed are increases has an effect to attempt to push the chain towards the top of the sprocket gears. What this does, for one is to try to stretch the chain, and wear the gears. The more important thing in the engine, is that when this occures, the chain riding toward the top of the gear teeth, CHANGES THE CAM TIMING! You can not maintain a consistant torque and power curve with the cam changing its timing under various conditions. Now, Nissan designed the system to turn clockwise, thus the reason for the strait chain to the crank on the right side of the sprocket, to promote a more stable positioning of the gears and chain assembly, and to make the system maintenance free for the most part. Now, since the cam, valve springs offer a SIGNIFICANT opposition to the cam turning, that transfers to the SLACK in the timing chain. So when you stop the accelleration of the engine in a clockwise direction, turning the cam, providing tensioning of the chain due to the drag on the cam/valve train. The cam and valve train components will provide opposition or resistance on the chain on the opposite of the sprocket, or left side of the cam gear. The cam then again changes its timing until the tension is enough to overcome the oppostion to the turning og the cam and valve train components. So what you get is a variable cam timing when you dont want it, it decreases performance, engine response and inconsistant operation of the rotating chain assembly. You want to see just how much change there is? turn the engine clockwise, take a reading on the timing marks, then rotate the engine counter clockwise, and note when the can starts turning, take the timing marks total, divide that by 2 and that is the amount of change in the cam timing you can expect to see. The hydrolic tensioner Nissan came up with works very well for a stock engine that wont see RPM levels over 5500 rpm's for the most part, but it really falls down after that rpm level. ASlso, since the hydrolic unit operates with the engine oil pressure, it to will vary in it's effectiveness. The unit that has been made to replace this system is very good. You can preload the chain trension, you have much beter control, as Tony mentioned, the effects of the thain that is spinning very fast. The cam timing is stabelized, the engine performance in stabilized. You dont have to worry about the plunger coming out, and that is worth 200.00 LOL so that is it in a nut shell. The part works well, and it is worth the money in my opinion.

Hi there guys, well I also got a SFP header for my car and it was a disaster from day one. I had to totally rework the part to get it to fit my application in the first place. Then I got it on the car and ran it for about 100 miles. The header cracked. I took it off and in the process of removing the header it was also warped about .250 from end to end. I called Frank and explained the problem to him. I sent it back for rework, including the coating color. When I got it back the header was still warped just as bad as it was before. The crack was repaired. The coating, well there again, the coater did not remove the first coating that was coming off in the hottest spots but rather just coated over the first coating with Black like I wanted in the first place. I called Frank again and called him on the repair, he wanted me to send it back in again. I decided to do the work myself, so I made a fixture, bolted it down and heated the piss out of it trying to get the pipes and flange to settle. Then I took it to a machine shop and paid 200 to have it resurfaced again. I haven't gotten the car running yet to test out my work on the unit. All I have to say about the whole thing is that I wish I had the equipment to do the work myself, this header has been a total pain in the butt, and I am not confident it is going to stay good so we will see what happens.

That is the rockwell harness of the rod.

I have never heard of heating a rod to pressin a wrist pin. You dont want to heat a part like that for any reason, if you change the coldwell of the metal, it will have disasterious effects on the engine. Kaboom!

I went with a 1.420 exhaust valve in my first head and that in my opinion helped my turbo. The new head that is being done is going to have a 1.470 valve. the 1.500 valve is to large for the 88mm bore, and I dont want to relieve the block to get the valve to fit the engine and not hit the bore. So in an answer, YES that larger exhaust valve is a better way to go, as was stated, provided you have the porting done along with the larger valve.

I had Dave Robello research out the bearings when he built my short block. I wanted Clevite bearings and he said he could not find them. So I got him a vendor, anyway, the michigan bearings are rated at 7000 pounds per square inch of pressure they can withstand. The nissan bearings are rated at 9000 pounds andthe clevite 12,000 pounds. You be the judge.

So my question to you is what is the advantage of lower static compression and higher boost aside from the boost gauge reading a higher boost level? The lower compression will enable you to run higher boost, but off boost the engine will have less power with the lower compression. Correct me if I am wrong, but dont you want increased power off boost, lower boost pressure to get to the same hp? Seems to me the L engine ( sepecially the zxt engine ) is doggy to be kind just off idle up to about 2K then when it starts building boost it then get some power. Have you been talking to steve? I still cant understand WHY running more boost is better then less boost. What is it in your mind that thinks higher boost is better, the higher the better mentality? The CORRECT way to build the turbo engine is to increase the static compression to 8.5:1-9.0:1 at the extreme with the quality of pump fuel now days. Thus increasing off boost power off the line. Decreasing the amount of boost to get to the same power level as compared to the lower compression engine. This will in effect increase the efficency of the turbo as it will not be pumping, or compressing as much air, thereby decreasing the heat produced by compressing the air, and keep the boost levels in the most efficient part of the turbo boost map. The higher compression level will also enable you to run a smaller turbo to get the same power, and thus will enable you to acheive a better spool of the turbo due to the smaller size. Make since?

Call Robello Racing for the part you want. This part is an improvement over the Nismo part.

The fuel pressue is normally set to 3 bar for the sport 400 package, the sport 450 package is set to 4 bar for additional flow to get the added hp, along with a differently tuned program. So it would stand to reason that your idle would get rich increasing the fuel pressure.

Give the .025 plug gap a try. As I said I had to do that with my setup because what was happening was a misfire, and it sounds like pinging when that happens. The AFR goes to heck and it sounds like pinging. Another thing to check just to make sure is the O2 sensor, make sure it is operating and not broken and not working. Your 3500 rpm level is right where the ecu goes from open loop to closed loop and vice versa so check that out. To bad you cant get a BIN file of the program we could get a look at. hope that helps you out.

Thats 3 bar static for the sport 400 and 4 bar for the sport 450 package.

I am assuming you bought the injectors from JWT. That being the case the injectors are run at bar static for the sport 400 package, and at 4 bar for the sport 450 package. I would recommend you reducing the gap atthe pluge to .025 and see how that works. The MSD is a good system, but it does tend to misfire under good boost loads. A wide band will not do you to much good, though, it will work, but undr boost it will give you readings that may or may not be accurate. Boost has a way of messing up the sensor readings. Still get some readings and go from there. I would try the point gap first. My car had a problem trying to go lean at the 5K range so it may also be the fuel map as well. Get as much information as you can to try to determine the problem, then give Clark a call about it. hope that helps.

I have just looked at your posting regarding the zxt and boy what a hard time you created for yourself. A few things every 280zxt guy needs to properly troubleshoot the eccs system. fuel pressure gauge and fittings. fluke meter. various hand tools. hot water. Factory service manual, it will tell you how to test most of the components. You can track down any problem with those parts. The )2 sensor should give you about .5 volts at idle and you should see anywhere from .3 to .9 volts depending on engine load. if you get .02 volts or higher, and the voltage doesn't make it into the tenth of a volt ranges when it gets hot, the sensor is bad. use hot boiling water to test the cylinder head temp sensor. use the ohms part of the meter to check the TPS. and if the car is not firing use the volt part of the meter to check the crank angle sensor, and AFM. this is a basic quick answer, but you get the idea.

Yes it is correct that sunbelt , and JWT for that matter have developed a cam rocker, spring combination that had a 70 psi seat pressure. As some of you pointed out the drag on the engine created by the valve train is significant. A good test to do for yourself is to turn an engine over with a 1/2" drive ratchet and then disconnect the cam and see how easy it becomes to turn the engine over. Anyway, the sunbelt and JWT setup is a good design, however the setup will cost you about 600.00 for cam, springs, and spring retainers. The one thing that made me pass on that setup is that you can only go 7200 rpm's withoug getting valve float. Sounds like more then enough right. Well in the perfect world that is very acceptable, however, have you ever missed a shift and hit a gear that was not the correct gear, do you remember what happened to the tach? The 7200 rpm level is easily surpassed in that situation, and myself, I have done that one time, guess what, it only takes one time and you have a piece of junk on your hands. So I went with the Isky solution, with a twist, and that is what I am going to run. The roller idea, well I have been thinking about that myself, having been in the roller cam/rocker field in my earlier years with Sig Erson I got a good amount of exposure to what works, and what doesn't and I believe I could design a roller setup that would work. Maybe one day I will do a setup.

Well I consistantly have run 20psi of boost with the car. The highest boost level I have run is 27psi on the turbo I built and then it was out of air. You will be happy with 20-23psi of boost. That level should take just about anything factory, or on the street.

Well there are a couple reasons. The first reason is that it is not needed to get oil to the chain, there is plenty of oil floating around in the crank snout area for any need of it. The second reason and more importantly is that it hinders the damper torque. I took mine off when my damper lostened up because of it. The part tore up the surface of my damper mating area, and then destroyed itself in the process. Then I had little metal shavings in my oil pan, not good. Luckily I had that happen Before I rebuilt the engine.

I bought a cam from Elgin, 200 and it was not what I specified, it was close but not quite. I know most of the schnider cams are mid to top end cams, for the most part. I just had Ron do a cam for me at Isky, and am about to install that part today. 179.76 with shipping to my house. The thing I like about the Isky cam is that it is basically a grind that was developed by Nissan racing, and electro motive in their hay day. I am running a turbo application, so we will see how it goes.

So is this something you came up with one day? Seems I have built about 18 pieces, sold 16, kept two for myself, in fact thare are a few complete systems out there for the ZX cars, complete. To bad though, I was trying to market those units to MSA a few years back for 850.00 complete and they said there just would not be the demand for the system. Well I got my system completed, and two other guys as well. I wish you luck, I would not worry to much about two 90 degree bends as it really doesn't detract from the flow. How do I know this, well lets just say I did a little more testing then just welding pipe together and hoping for the best.

I hsve done some good testing on my turbo setup, you may want to check out my page to give you some ideas. http://www.angelfire.com/extreme/280zxt