Tony D

I would disagree that lack of throttle response and lag are the same thing. Lag is a time based phenomenon form application of full throttle to onset of full boost. If driven CORRECTLY a turbo car of modern design will NOT exhibit any noticable lag. But to the question of "how"... You use a turbine that will spool the compressor section at a very low rpm. Oversize your wastegate. Use a computer to control it that senses rate of change on throttle position to positively close wastegate (derivative action) to prespool the turbine (udersized remember). At the SAME TIME, you have another blowoff valve controlled via solenoid to control plenum pressure to whatever the minimum flow of the compressor should be. This is similar to industrial turbocompressors. If you have a VNT turbo, this would be EXCEEDINGLY easy to overfeed the plenum at even idle. You wimply blow off excess boost from the plenum so the compressor doesn't have necessarily a lot of PRESSURE at idle, but TONS of flow. Thie results in an IMMEDIATE pressure response, as you use the same throttle position rate of change derivative action to control the plenum blowoff valve. All that flow translates into pressure when you slam the blowoff shut! I hope that all makes sense. From a control standpoint it's pretty easy to understand.

I can tell you firsthand that with Ms you can build 12psi of boost at 1200rpms using their rev limiter function... You can also burn down the turbo doing so.... I have no "lag" problem, but use the right word, as "lag" is the TIME difference between full throttle application and the onset of FULL Boost Level. The "boost threshold" is the mimimum RPM the engine must be operating at to MAKE FULL BOOST. They are TWO DIFFERENT THINGS. One is Time-Based ONLY. One is RPM-Based ONLY. TIME=LAG RPM=THRESHOLD

Mole weight... AAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHH! "Moley Moley Moley!" "Moooooole!" Couldn't help myself... I digress...

My time in first gear was less than 2 seconds from a dead stop and hit redline, second gear was 3 or so seconds (again to redline) and then third was again on full boost as I hit the gas. I never dipped below 17psi unless I was drop-throttled. The exhaust I was running was a mandrel bent 2.5" out of the stock turbo housing, into a merge that split to twin 50mm pipes. Technically this should flow equivalent to a 2.76" single, so it would seem I am more restricted than you are currently! I would look to loose wastegate and the tuning, that is the only thing I can think of, with the .63 I was slightly slower to spool initially, and threshold went up from 1500 1700 to 2200 or thereabouts. But once on the cook above that point, if I floor it, it jumped to full (17psi) in a rapid sweep, you cant even get "onethousand" out of your mouth starting when you hit the gas before it was at full boost.

YAAAAAAAARRRRGGHGHGHGGGG! That is BOOST THRESHOLD, not LAG! AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAH!

Simple, it's similar to the CART Systems (similar, dammit, SIMILAR!). The GTR has always had ITB's and that plenum has a soft blowoff. If they modulate the plenum bleedoff, keeping the turbo spooled via a separate wastegate you end up with positive boost turbocompressor system. The plenum bleeds off to a minimum flow line based on the surge characteristics of the wheel/turbine, and the most negative pressure you will have is on total drop throttle--and that volume is probably only about 43CC per runner between the throttle plate and the back of the valve (being as close to the head as the ITB's are!). Is this a conspiracy? Someone recently hammered the idea of ITB's in turbocharged service, and "saw no reason for them but bling factor"---he obviously never heard of a positive boost turbo system---but such is par for the course for that site... Follow, Amigo?

1,000 Apologies! I got blindsided by work, and have been running since I returned. I saved your phone number in my celphone so I can call you to check when it's scheduled to be back. I will be following JeffP when he takes his car down to Clark for final tuning in ElCajon at Jim Wolf, so I should be in the area, Jeff wants to make id down there next week, so I'm hoping it will all work out when your unit returns. I haven't even gotten my rental backhoe to dig my drainage ditch---rain is COMING SOON and I GOT to do that! I just found my stimulator and extra boxes, so we are good on that point! LOL up at 0430 tomorrow to be in Thousand Oaks by 7... BAH!

Uh, NO IT'S NOT! The "cartoon" you deride is an ANIMATION OF A REAL LIFE SEQUENCE shot on the Tokyo Freeway System in the mid 1980's. Originally the series was "in the flesh" but later went to Anime after the Magan Popularized it in that format. I have the same sequence on old VHS, and THE CAR IS REAL. I have SEEN IT RUN!

BTW, my T3 pumping through triple mikuinis would go from 0 to 17psi in an eyeblink with the .43 housing on it at any speed above 1500rpm, with a choke at 5500rpm. When I changed to a .63 A/R turbine housing, the runup to 15psi would take about the same time, less than 1/4 second at 3000rpms, probably 1/2 at 2500. It was considerably slower than when the smaller JDM housing was on there.

That is exceedingly easy to answer: you have an improperly sized compressor section operating outside the design parameters! JeffP's engine will go from 0 to 23psi in an eyeblink at 3000rpms using his last scroll compressor combintaion. 2500 actually.... With the new compressor there is a 500rpm higher threshold, so if he nails it at 2500 now, the car gets bost, but not full boost till 3500. If he nails it at 3500rpm, though, it goes from 0 to 25 instantly, just like before. You simply have a turbo combination working so far outside the proper operating range, with so much volume to fill and such a small compressor filling it, it takes forever. You really need to come down to Orange County and go for a ride in Jeff's Car! When you size it correctly, turbos are savagely efficient and responsive!

Sounds like it's ocme full circle, and back to my definitions of Boost Threshold and Turbo Lag. If you want the threshold lower, then size the compressor turbine package accordingly, and tune for efficient combustion. Also driving in the right gear for the speed will make threshold almost irrelevant. Don't try to tweak too much with timing or mixture, as ultimately you aren't efficently producing the power you would were you turbosized and fueld correctly. If you want a "less laggy" turbo when driven correctly (with less than 1/2 second from no to full boost) then realistically you need to look elsewhere for that kind of response, lag will always be less than 1/2 to 1/4 second when sized properly. Where full boost is made is boost threshold rpm. Above boost threshold rpm, time to full boost is turbo lag. Below boost threshold rpm, time to full boost is incorrect driving techinque!

So Follow Me on This One, Guys: If the SX Gearbox is 2 to 2.5" longer than the original Z box. And the differential Relocation of the Pre-71 cars is about the same... Shouldn't you be able to use one of the early pre 71 driveshafts in the back of the SX tranny to mate with a differential in the "late location" without having it modified? Reason for asking? I did three or four differential relocations for people and have those old driveshafts laying around for the day they want to "return the car to original and I can charge a premium for the parts because everyone else threw them away" (Or that's what I tell the wife!) If this is the case, heck, I got the trannies, and I might have the driveshafts to boot! WOO HOO! Looks like SX / KA tranny shiftlever relocation is about where the early trannies were shiftlever wise, too! Anyone, Bueller?

Oh, and it ain't no Cartech kit!

Ahhhhhhhh SSS "Blue Car" it's so nice to see a second generation captivated by the Anime interation of what was live video in the Mid 80's... That is the Anime Version of the SSS (Speed Shop Sinohara) "Blue Z". 600HP, twin turbo, blowthrough carburetted Mikuinis.... I have the original Video (live, not Anime) somewhere but magnetic degredation makes for a bad viewing. The specs are in a box that comes on the screen during the "Making Of" section of the video, very impressive car, and sounds better on the live version. Blue Flames out the 5" tailpipe from freeflow and slightly rich mixtures on lift throttle, not as a result of Ricer Add-Ons. The video is pretty stirring if you ever have a chance to see it. The Anime is good, but having made the trip to the mainland and seeing the car at Fuji Dragway burns it in my mind! To answer the question, (spelling may not be right) but the car is Speed Shop Sinohara, or Shinohara.

EEH, it's nothing. Take a look at JeffP's cylinders from when we took the head off last year! And that was still "nothing" it's going back together right now, cylinders not touched. I might take a look to see if the PISTON LAND is damaged causing the marking---but the cylinder wall is fine! My bet is broken land, or ring bit causing the irregular wear pattern. JeffP's was on the opposite side, on the piston thrust face, far wider, and a result of piston clearances at....uh....245+ Degrees Farenheit! If it didn't seize then Jeff, it aint going to! LOL My concern would be with the piston itself as that should not have a wear pattern there!

No need for a rebuild and using the Maxima Case, you simply use the Maxima Bellhousing and torquecoverter/flexplate on the Starion Turbo Tranny (I forget if you need the input shaft, it falls right out anyway, so it's no big deal swapping it!) They are both the same JATCO transmission save for the Turbo Specific Enhancements. The Starion was a 2.6L Turbo Tranny, and like the Turbo Three Speed used in the ZXT's from 81-83, has some extra clutch plates, different valving and shift action, higher line pressures, etc.... Works, but is the same PITA as installing the four speed autobox. Obviously you aren't using the power in overdrive, but having that nice .67 gear for highway cruise is niiiice if you have the torque to pull it off!

Dang, who else said that? LOL!

JM, I won't buy the MSA Shifter for the reasons stated above. Steve Christensen mentioned using the truck shifter "as an interim step" between stock and what he produced. I probably should have mentioned that, but I didn't talk to him to refresh myself on his story till later last evening. Yes, the truck ieda will shorten the throw, and you can see an improvement, but compare apples to apples: cut the shifter for the handle at the same height from the pivot point as the stock handle to determine actual "shift legnth decreased". If you work it out or even draw it out on paper, you can see for every say .1" of pivot to end legnth you remove south of the pivot, you shorten the linear distance of shifter throw "X" amount. This does come at a increased effort tradeoff, but we are talking ounces here, in reality---it takes a ounce pull scale to check this stuff. This is given long end legnth being the same. Now, if you take the long end of the lever and start shortening it, you will see the arc it travel through is ALSO reduced, but the comparitive effort (again ounces here!) to gain the same reduction in shift legnth will result in a larger effort than the decrease on the short end. Steve designed his short throw shifter to be the same assembled height (if not a bit taller!) for wheel to shifter convienience, without the additional effort required when cutting down the long end of the lever. While your throws may be the same, (again ounces here!!!) the effort to throw the lever will likely be measurably higher than the SMC unit. But Agreed, Steve did say the truck shifter "is a good in between step, but people are too lazy to cut down the lever much less install new bushings!" And at that point the conversation digressed into the maladies of manning the phones and explaining this kind of stuff to non technical people when he worked at Nissan Motorsports (LOL). As Technical Ninja has noted, he is approaching the "magic 25mm" elongation of the lower section. Half an inch was not enough (sound familiar?) My numbers are vague because though Steve mentioned them in conversation once a long time ago, I don't remember them, I was thinking 2", maybe it was one inch.... Anyway, it looks like the number below the pivot is subject to a maximum of 25mm elongation (what would the total distance be from pivot to cup end then?) and then upper lever shortening seems limited to stock and maybe 10mm shorter. What may be a better way for the discussion to progress since Technical Ninja posted real numbers if for us to compile the differing legnths of the rods used on short and long pivot ends, and list them here. We know the stock shifter rods in the transmission require a "linear movement of Xmm" to go from N to any given gear up or down, and from that it is a very simple geometric diagram to figure out actual "Human Interface Linear ACtion" required on the long end of the stick. Also, as an aside, Technical Ninja is very astute, Steve did mention that in order to get the right "feel" a heavier knob was used! So whatsay we standardize our conversation here, and start dealing with pivot to end legnths, and from there it's all a matter of simple math (and it also gives people something to measure with calipers when out in the junkyard!)

"You are right I am quite happy with 12psi at 3100rpms but if I could tune it so it was at 2700 that would be even greater." Don't confuse Boost Threshold with Turbo Lag. What it appears to be here is that you want full boost at a lower rpm, which means lower threshold. You can artificially tweak some of those parameters like Bernard suggests by running advance one way or the other. I know I could get 17psi at 1000rpms on a stock turbo with a 5ATDC timing setpoint and flooring the pedal for full fuel. Turned the turbo into a gasturbine. Also will melt down your wheels, blow holes in your housings, make them glow orange cherry red at idle while doing so, melt the braze joint on the oil feed line... etc etc etc... Nothing is free, for keeping the car on boost instantly, drive the vehicle in the proper gear for the speed you are at, otherwise size the turbo for the threshold rpm value you want full boost to occur. Anything else is a patch for an improperly applied turbo, changes can be done, but the temps at the turbine will increase and life may be shortened. Flatshifter WRC Anti-Lag Turbos don't last very long compared to stuff not subjected to that abuse! I agree with the last few posts: most timing will optimize power. Optimize power, not necessarily trim threshold using timing.

What would the possibility be of simply turning off the notches on the stock 81 CAS trigger wheel, and renotching it to the current required configuration? This would give you a wheel that is indexed via a dowel pin from the factory, and transferrable to another pulley should the dampening ring fail (which it WILL DO given enough torque inputs on a turbo motor).

"I attended the PRI trade show yesterday." Dude, you suck! LOL Reading the guide to the show sine it arrived before the last trip the NJ! Are you partaking of the "Ladies Steakhouse" advertised in the guide edition? I can see you there, in Orlando, ordering steaks on the, uh...."Barbie"! I like the Brackets idea, that was the direction I was going for the 510 and the Camden C80 I have laying around (about the size of the stock A/C pump...) Anything Lysholm is my friend! I digress.

You show me a photo, I can look on any number of older removed CA Spec manifolds in the junkpile and tell you what I have laying around, if you are interested in used parts.

How in the world did you get an N/A distributor to interface properly with the Stock Turbo ECU?

I will be home 1120pm Monday night, have a doctor's appt tuesday AM with some jnkyarding planned for that afternoon (hot finds phoned in to me transcontinentinally!), so if you have transportation to just about anywhere, I can pack up the stim and a fresh 9V and bring my laptops to see if I can connect to your box. I had a lot of trouble with what I thought was electrical issues, and all along it was my LAPTOP! If it could go wrong, it did on my system! LOL 909.286.2981 is my cel number.