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Tony D

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Posts posted by Tony D

  1. Uh... yeah... "The security of the exhaust valve seats"!!!!! :blink:

     

    Seriously, why did they feel the need to stake the seats in that fashion? Not enough heat on the head and no N2 to shrink the seats on installation---so they figure "punching them will tighten 'em up good 'nuff!"

     

    I would have serious reservations on using that head as anything other than cutting up for porting information or other experiment. I mean, if you yanked out the valves and made sure they were installed correctly then I might use it...

     

    But with those punch marks there... I'd wonder WTF they were trying to shortcut!

  2. The pedal cluster unblots as an assembly, it is near a spot-welded chassis component that runs 'through' it to support the steering column, but the pedal box will come out separately.

     

    As noted, it's kind of a PITA to remove as the dash comes out to access it the easiest...but it does come out! :(

  3. Well, I see it's too late for my warning of "Don't forget to slip the section of Sch 80 Pipe over the lines to keep them intact should the clutch come apart..." :(

     

     

    Make yourself a 1/4" thick plate, and bolt it to the chassis to cover your lines in the vicinity of the plane of rotation...

  4. Oh, I assumed you ran aftermarket A/C like I do in those temperatures.

     

    You do remember my stories about going 110mph across Iowa in 104F and 90+ R.H. with a 70F interior temperature and a temperature gauge right left of center???

     

    Trust me, if you can keep your engine cool in SoCal/PHX during the summer months, you got a 'cross conuntry cruiser' with A/C on full blast! I know I did! :D

  5. Make that 32+mpg on L28eT's

     

    Mapping isn't a big issue---when it goes to light cruise lean the heck out of it just like stock.

     

    Weight is the same as they will have the same equipment, this is a non-issue...

     

    Look to General Motors and their GENIII3800 in the Bonnevilles and other humongo cars, which regularly get mid 30's at highway cruise. Torque is your friend, and that nod goes to L28. And if it's turbo, even more torque.

  6. Methinks the Z31 Guys are huffing the lacquer again.

     

    Those are seat-stakes and nothing more! Personally would scare the hell out of me if they think staking the exhaust seats like that will do anything material.

     

    Singh combustion chambers aren't accomplished using a center punch in the vicinity of the exhaust valve seat!

    That's a wild-arsed guess to say those are Singh Chambers...and a poor one at that! :angry:

     

    Singh-Chambers are very distinctive, and if you google it, you will see what I'm talking about. They are not cylinderical punch marks, and nowhere near the valve seats!

  7. TDC is determined between timing marks and actually indicating the engine. Read the FSM (81 Turbo Supplement) for which marks are TDC on that unit. I had some stuff on that when I used that setup on my MS---it's on sharkie73z's cardomain page someplace---you can check it out, only 14 pages to sift through. Mostly useless information anyway.

  8. Lets compare southern california in april to where I currently am working: Southern Thailand in April.

     

    32C is 32C right? Unless one is 20% Relative Humidity, and another is 2-4C hotter, as well as 90% Relative Humidity...

     

    There's "Hot" and there's "HOT"...

     

    Frankly, handling Mexicali at 50C+ in July and August is easier on me than Thailand at 40C any time of the year. :(

  9. Actually I believe the diameter of the piping is inverse to dB. Larger usually means quieter. This was the way it was on the Corvairs which basically had mufflers right on the header collector and then out the back. The larger diameter exhausts which you thought would be louder had a much lower and mellow tone. Smaller diameters on the Z seem to have a 'snarl'---much more 'pop' rather than a low-throated rumble. It may be where the auditory effects are masked. People find an F15 at idle wildly loud (and it is...) but mostly because the noise is RIGHT in the irritating zone of human hearing Hz - Wise. Perhaps the larger diameter pipes will 'meter' as loud, and it's just the human ear that 'seems to think' it's lower noise.

     

    And really it's that perception that will get you the ticket! If it 'sounds loud' it is, and the ticket gets written. :(

  10. I would disagree: tune for those hot days! You will only be rewarded by being able to drive in any weather without making excuses. I would drive out to Palm Springs to work the long grade back into Riverside during the hottest parts of summer. As a result of me tuning at those temperatures, I had absolutely no other issues the rest of the year. Then it was something like 110-120 (and don't even get into macadam thermal layer ingestion temperature! I was sucking in air at over 160F to the turbo in some cases!!!)

     

    If you add methanol, that kind of temperature won't be a deterrent, but then you have another tank to fill and worry about. I didn't have methanol on that build likely I would today since the injection technology has progressed so much. I had it (water and water/methanol actually) on the Turbo Corvair...and it was tuned on the same grade, at the same time of the year!

     

    Tune when it's hot, with the A/C on. Either you reveal your cooling systems' shortfalls, or your tuning shortfalls. Either way, in the long run you will be rewarded with something that is long-term troublefree.

  11. I wish that Hybridz would do a comparison with engines and modifications as was done with the wind tunnel experiments. Starting with a baseline on a dyno and start tuning and adding on "bolt-ons" and read the results. I would throw some money at that as i did with the wind tunnel tests-it would interesting!!

     

    I got everything to do that(again), but it wouldn't be the same as the wind-tunnel as you would have to restrict yourself to doing it on the same engine or car meaning breaks in time to do the changes. Renting a dyno for a day is easy enough, and not that bad if you can do it during 'off-peak' times, but effectively changing an induction system quickly... and then optimizing it.

     

    Probably the best way to do it would be to run and tune each setup separately over a period of a couple of weeks/months, and then shelve the components in prep for a 'back to back test' which could then be done over the course of one or two days. Technically the results should be the same but reaccomplishing the tests back-to-back on the same dyno, on the same day would dispel the 'dyno drift' argument that would inevitably creep up over testing individual components separately at different times of the year, etc.

     

    But I do have all the components, and more than enough 'spare cars' with L24's L26's and L28's in them. Three chassis ready to prep one with each engine. And I know an amicable dyno operator. Now to get some magazine to accept the article...

     

    And get the time to do it... :P

  12. Sparco and some of the other Silicone Vendors have 'tree' hoses--that is standard size turbo inlet sizes with a 'smaller branch' of anywhere from 5 to 25mm diameter.

     

    I made mine from a section of 3" muffler tubing. Had a mandrel bent 3/4" pipe that I made a penetration and welded in place. Then connected the muffler tubing to the turbo, and the 3/4" pipe to the blowoff (recirc) valve...

     

    The front portion of the muffler tube was like a CAI setup, and eventually went to a K&N Cone Filter.

     

    The 3/4" pipe pointed to the turbo wheel, so the air blowing down poofed to the turbine wheel to hopefully keep it spinning faster with no force coming from the turbine side on drop-throttle.

     

    My understanding is this is how the old 917's were plumbed.

  13. It will give you that. Mine would make 17psi at 1700psi (where I ran most of the time)

     

    At low boost on 10psi I could get that off-idle really. From a standstill with a clutch dump I would have 17psi if I went WOT simultaneously. I would go positive pressure when free revving with the smaller surge tank. This didn't happen on the larger tank.

     

    Frank 280ZX has a similar setup running 10psi on triple blowthrough webers making 231hp to the rear wheels, and his spool is very similar to mine. On his ITB setup with megasquirt if he 'fast idled' the car at 1700 he was making 2-3psi (AT IDLE!)

     

    I think you will really like the response from the engine. For a daily driver it will be great. I loved mine.

  14. I just want to add that when you follow the "just turn up the boost" mentality, what happens after a certain point, is that the restricted flow path will cause the air to "bunch up"; and at that point you are beginning to make more heat than flow. Heat is the result of trying to flow 10 pounds of air through a 1 pound path...so to speak. The analogy could be trying to push a sponge through a funnel. Pushing harder on the back of the sponge will cause it to bunch up and compress further, in the wrong direction, making it all the more difficult to fit through the bottleneck..."heat".

     

    This belies the physics of what is really happening and is misleading as to what is really what is going on. PV=nRT, boyle's law says the higher pressure you have the more heat produced. It's nothing about a bottle neck in the downstream it goes directly to the pressure ratio and efficiency map of the turbo.

     

    If you walk outside the most efficient area of the compressor map, you make more heat per psi produced simply through inefficient compression and internal recirculation. Add to that higher pressure (meaning higher pressure ratio) means that more heat is also produced.

     

    Heat is produced by pressure ratio, NOTHING ELSE. This is the physics of compression. The FLOW portion puts you on the map in an efficient or inefficient portion of the efficiency islands. The PRESSURE component gives the basic heat generation. It is straightforward on a 3:1 Comp ratio that you will make X heat at an 88% efficient compression area of the map.

     

    Move to the 78% portion of the map, and you will make X heat + the additional heat generated due to being 78% versus 88% efficient in compression.

     

    This can be very significant.

     

    This is a quadratic equation with the efficiency of the stage of compression a fractional exponent, but the math is something anybody with high school pre-calc or algebra 2 could work out, really.

     

    The same thing goes for any compressor.

     

    What you do with the "crank up the boost mentality" is move the point on the efficiency island where the compressor is operating from one of high efficiency, to one of lower efficiency. If you run vertically on the compressor map, you would get more heat at the SAME pressure due to the efficiency loss. Add a vertical and horizontal component to the equation and you end up set for poor efficency.

     

    Rarely do you move to the right on the compressor map in terms of efficiency, the 'crank up the boost' people move up, and to the left on the map almost universally. And look at a turbo map for efficiency islands and you can see the dropoff plain as day.

     

    Through engineering, they bias the maps wonderfully to compensate for this (compare a turbo map from 1970 and 2010 to see the change of the island shape!)

  15. Yep, detonation damage from inaudible and what most people think is 'harmless' detonation long-term.

     

    Remember people say to check your plugs for signs of silver (aluminum) after some detonation---now you know where it comes from! Either the head, or the piston crown.

     

    Ceramic Coating may be the least expensive alternative to salvage the head, but the damage between the seats won't be helped by ceramic... Lost material there means the chance of a lost seat eventually.

  16. DO NO BLAST ANYTHING!

     

    Nothing is on the combustion chambers that won't be taken off with proper solvent and some soft scrubbing with a toothbrush or maybe a brass brush.

     

    If you blast, you will peen over edges of a crack making it very hard to spot.

     

    After the combustion chambers are thoroughly cleaned (last with lacquer thinner) then get some SPOT-CHEK from a kit (they would sell the kits at McMaster Carr for $70 some time ago) First some red dye penetrant, followed by white developer. Any cracks will show up as a red line in the white paint.

     

    Follow the directions in the kit, and with a cleaned head with the right solvents you will straightaway spot any cracks.

     

    Zyglo is nice, but expensive. Spot-Chek is the second best alternative, and can be used on almost any non-ferrous part (like pistons).

  17. I preferred my T3/T4 hybrid with the .48 A/R over the stock .63A/R as full boost was available at 1700rpms compared to considerably more than that with the 'stock' turbine housing.

     

    Some say it was 'restricted' due to small size, but it fit my power point requirements, and worked great. I wasn't making a 7000rpm peak-power dyno queen, I ran it at Auto-X and it was like a supercharged car with that small turbine.

     

    Many Auto-X "Turbo Haters" would simply repeat in amazement "This is turbocharged? This car is turbocharged?"

     

    Paradigms are a heartbreaker when they go away!

  18. I'm guessing you mean a change of the hot side plus 8 to 10 psi of boost to make the added 100hp?

     

    Argh....

     

    To complete the threadjack and thoroughly change the subject---all three of the 'combatants' in this digression are wrong. The change to the GTX will give you more power at the exact same boost levels---I can imagine EXACTLY the dyno chart he has at 20psi it's the same one we are getting on JeffP's car around 17-18psi. Car makes more power at 17psi than it does at 20, but at a higher RPM. Changing to a GTX which has more mass flow capability at a given pressure ratio will result in more air at the same PSI. This means the car will make more power without an increase in indicated boost levels. In his case, the power peak will move to 7500+ at 17psi, rather than being stuck and flatlining at 7000 and up at 20psi. (Making slightly more at 17 and 7500 than at 20 and 7000.)

     

    Boost doesn't make horsepower, guys. FLOW makes horsepower! Boost is merely an indication to resistance of flow.

     

    Given the same everything save changing to a GTX turbocharger, the car will make MORE horsepower at each given boost level than it did previously.

     

    And before you guys argue the point, swap the turbo and check it out...then come back to the thread.

     

    This is rooted in a basic misunderstanding of how the turbocharger works, and what is actually making the power in a turbocharged engine.

    :rolleyes:

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