speeder

If boost is wrong I don't wanna be right.

I've had good luck with Turbo Specialties when dealing with "What Fits " problems. Talk to Reed. Turbo Specialties

I'll post most of this in the appopriate forums later,(Is there some sort of etiquette about changing subjects of a post?) but- The one piece front end was from Arizona Z car - a paper-thin racing piece that I had to bond - in headlight buckets, flares, and hinge mounting points. Pain in the A$$ to install, make fit,strengthen, and make look good. The cage is a Safety Devices bolt-in deal - To install it I cut out part of the sides of the dash for the uprights to fit through, then after installation filled in the cutouts with foam and installed a full face dash cap trimmed for where front uprights exit the top of the dash. The dash was already trashed on this car so I really didn't mind cutting it up. Looks good now, however. BTW, don't buy a bolt - in cage, have one built to fit your car. I'm not happy with the fit of mine. The diff mounting mod raises the rear of the diff up about 1-5/8" to get the halfshaft u-joints in their happy zone after a 3-1/2" lowering with coilovers.The frame member above had to be notched (and the notch reinforced) to clear. The front of the diff was raised with spacers to get an acceptable driveshaft angle. All this makes me tired just talking about it - I'm glad its done - but you know what they say about Hot Rods (and extreme Zs) - They're never finished. I keep thinking all the hard stuff is done but.... you know.

Hi Mitch- I have a Camden Blower with JCR Manifold that I'm going to put on my '78. This will probably take a few months to finish as I'm converting the manifold to EFI. I'll use the Haltech that's currently on the car. I'm fascinated by the prospect of a straight-6 Z with low-end torque. So much for my "keep it simple" '78 Daily driver I'll let you know how it works out.

The resolution and accuracy you get with a WB is worth the trouble of switching the laptop between ECU and O2 unit - the 3 measurements the FJO logs are all I need for serious tuning, especially for the initial setup of fuel maps. Substituting the WBO2 for the TPS input on my TEC2 isn't an option for me - I want to keep my TPS connected. I'm going to build a circuit to convert the analog voltage output of the FJO to be compatible with the TEC2's EGO input - Wintec2 has an EGO sensor calibration function but the sense of the input voltage swing must be inverted before using. FJO output goes 0-3.1V for rich - lean, while regular O2 goes 0-1V lean - rich.The Electromotive Tech Support guy said they were working on an outboard "inverter" circuit for this pupose but I havn't seen it yet. I was talking to a guy with a Buick GN who had a Fel-Pro ECU installed - it uses the NTK WB sensor and looks really capable.

Okay, I finally sat down and exported an FJO Datalog graph to my webspace. Check this out: The black trace is RPM, blue is manifold pressure, and red is AFR. Don't try to critically analyse this data because it was made during my first run with 52lb injectors, a too-small wastegate that wouldn't hold boost at set-point, and "first -try" Electromotive fuel maps. But you can see how this could help with tuning. Shortly after this data was taken I had to send my turbo off for a rebuild/upgrade (probably damaged by compressor surge) and I'm dyin' here waiting for my new turbo/wastegate so I can get back to this toy I'll post some tweeked-in graphs when I get them.

I'll post some of my graphs as soon as I get time to figure out how to export them from my laptop. Still recovering from an extended visit to the In - Laws' last week. I bought my FJO setup used here locally - I can't recommend a source.

Pete's 3rd Choice for Me!

-I'm on the obligatory trip to the in-laws' this weekend and this is the first time I've been able to sneak off and post to HybridZ- Like I said, this is an internal wastegate, and yes, the bypass passage from the swing valve to the exhaust side of the housing is clear. I''ll be talking to my rebuilder tomorrow and will pop for the Stage III wheel and housing, staying with a .63 A/R turbine size. I've heard some people have had to go to oversized swing valves and ported passages with this T3/4 setup (mine has the ~1/2" dia. port) - indicating that what I have isn't up to the job -so I'm going ahead with the external wastegate. Thanks to everyone who has helped with this - your insights and recommendations are greatly appreciated. Probably prevented me from going to a too-big turbo at this time. I'll let you know how the bigger exducer and upgraded wastegate work. Hoping to have that done in a couple weeks.

Pete, I can't remember street names any more- It was in back of the high school in Larelton Forest Townhouses - out near I95, PG County. I'll put together a more coherent writeup of my diff install with pics and post in the right place.

1stgenZ: I used to live in Knoxville, too. j/k. Front end was from Arizona Z Car - Took a lot of work to make it fit, strengthen it, mold-in headlight buckets, and build hinges - Very poor quality. Probably just as well he doesn't sell fiberglass any more.

Now that I've sent my turbo off for a rebuild, I've had time to think about this. A little history: When I first got the car going earlier this year, this turbo and wastegate worked well - pretty much made and held boost wherever I set it. This was with 2-1/2" dp, tailpipe, and turbo muffler, 3:90 rear, smallish intercooler, and 35lb injectors. I then went to 52lb injectors and a BIG Spearco intercooler, and tuned accordingly. Thinking back, I'm pretty sure that's when the boost creep started, but still wasn't too bad. My next round of mods was soon after, when I went to a 3" downpipe, 3" exhaust, straight- thru muffler, and 3.36:1 LSD Gears! That's when the boost started to ramp straight up out of control. The rate of rise was too fast to be called boost creep! It was way worse winding out the higher gears. In lower gears, boost would linger briefly at the set point, then start to climb. I know that the big pipes will result in more exhaust flow, but what will that big a change in gearing (and engine load) do to boost control? (I made this change after reading many posts by the big horspower guys - Scotty foremost - who discussed tall gears for best performance with a turbo - I was going to do an LSD, and had that 3.36 R200 laying around...). Thermodynamics has never been a strong subject with me... What do you guys think - will improved exhaust flow and taller gears cause my symptoms? It really seems to me that I'm simply flowing too much for the internal gate. If this looks like a good theory, I'll do a good big external gate, and stay with the T3/4 as is - for at least a little while longer.

I have just aquired an FJO WB O2 meter with datalogging capability - I have rigged a 3-bar MAP sensor to the Aux input and can log AFR, RPM, and Manifold pressure simultaneously to my laptop for later playback and printout. Awesome tuning tool. I was using this to tweek in my L28 Turbo with Electromotive when I ran into car problems I have to fix before continuing. Drives me crazy. I'll see if I can post some pictures of some of my graphs - Will keep you guys posted on progress.

What I was referring to in the quote was a test to make sure that the swing valve and actuator were working - I have an air regulator set at 10psi, hooked this to the "pusher" side of the actuator diaphram, and watched the lever move to the full open position. I listened for air leaks from the diaphram while doing this and heard none. My reasoning after this test was that if the wastegate is open fully with 10PSI on the diaphram, then I don't have enough bypass flow from the gate when fully open to control boost. Today, with the turbo off the car, I moved the lever and looked at the swing valve every way I could imagine, and could find nothing weird. This is not a very complicated mechanism! Earlier, with the car all together and running, I simplified my hookup with a single connection (about 1 foot of 1/4" id hose) straight from the compressor outlet to the "push" side of the diaphram and still have almost no boost control (Climbs right up past 20PSI) even with the actuator arm set for maximum length to give me the lowest preload/set point possible. I even pressure - tested the hose. I'll got to the shop tomorrow and double- check everything again - this has to be something simple, especially in light of many similar setups being used by others with no problems like this. It gets worse- the last time I spiked the boost like this I think the turbo went into compressor surge - I checked side play on the shaft and it's bad. Looks as if a rebuild is in order.

For those not following my earlier adventures, I lost control of boost (too much) with this T3/T4 setup (internal swing valve and dual-port actuator) when I upgraded to a 3" downpipe and straight through muffler. The compressor is a Super V. I've pulled my turbo and found that I have a .63 A/R (Stage II) instead of the .48 that I thought it was.(There are two part numbers on the flange, the one I could see was for the .48 and the other was for the .63. inside the inlet was stamped .63) Although a turbo upgrade is coming, I would like to make this setup work for when I move it (along with the 3" exhaust) to my other car. Also it may take a while to get that setup together. I can apply 10 psi to the actuator and observe the valve open fully. The actuator arm is lengthened to the point where there is minimum spring tension holding the valve closed. Opinions please: Have I missed something? Should I keep looking for some kind of problem or just assume that I need the .82 turbine housing and go for it? Thanks,

Hey, I didn't help any with the lengthy non-relevent answer posts, either. Sorry, new member gaffe. My Magneflow Race Series was a little pricey at about 160.00 - a really good looking piece, stainless steel wool packing, nice integrated tip, should last forever.

We're getting way off the subject of "muffs", huh? Hey, I used to live in Laurel 20 years ago. Thanks -It's cool that my car is getting so much attention, and I don't mind telling about it. The color is a 1990 300zx midnight blue pearlescent- Don't know the name or number - It's the darkest blue in the book - looks black at night. All my cars are blue. My daily driver: My wheels I bought circa 1994 for a previous Flared Z which got wrecked - They are HRE 16" modulars, the style sadly is no longer made. 9" rear and 8-1/2" front, running 1-1/2" positive offset to fill the IMSA flares. The moustache bar pics show a bracket I made to raise the diff upwards by about 1-1/2 ". I needed to do this because the car is lowered by about 3-1/2" and the halfshafts were raisin a ruckus when the boost hits. The only problem with this trick was that the diff now made contact with the transverse frame member above. I then notched the frame and embedded a 1X3" square tube with gussets to strengthen the notch. If you look close there's a picture of the notch, along with before and after halfshaft angles on the site. Reduced the halfshaft angle to 4 deg upward from 12(!) degrees and the noise was gone.I probably should discuss this over on the driveline forum, huh? I think others have struggled with that problem.

As with so many other aspects of this project, my problem was that my objective kept changing during the 6 years it took to get this far. This car was originally going to be a super light, stock bodied, Weber'ed 4:11'ed fun car! Then when I was buying a turbo, I went for max response. I quickly outgrew the turbo as tuning progressed. The car will remain primarily a street car - but is definitely going the "max effort" route. I already have the built motor, big Spearco, Electomotive, and 52 lb. injectors. I really appreciate the help with turbo trim - I'll be buying my T4 this week, the manifold is being adapted as we speak. Is there a better compressor than a 60-1 for me? Man, gotta love Hybrid Z - should have found it sooner.

Thanks guys - The spoiler is a Kaminari wing from MSA. Expensive, kinda ricey - looking, but dammit, I like it!

Thanks Lockjaw and 980mak - Looks as if the .63 is it. 300 rwhp is about where I want to be (for now ).I'm looking to run about 15-16 psi boost. I'll remove the turbo and measure the exducer tomorrow - If I have to do more than replace a turbine housing I'll accelerate my plans for the T4/60-1 and Racegate. I have been planning to move my T3/T4 to my '78 daily driver and upgrade the turbo on the '77ZT which is a much more serious car.

Just checked the part number on my T3/T4's turbine housing and it turns out to be a tiny .48! No wonder I have problems controlling boost! It was marginally good (just a little creep but real responsive) until I put on a full 3" exhaust with a straight - thru muffler, now I have hardly any boost control above 4000 rpm. Do any of you straight 6 guys have any recommendations? (.63 or .82?) I have a "Super V" compressor on this beast. Would like to hear what turbo trim you are running and how you like it. I'll try a new turbine housing before going to an external wastegate. Thanks.

Thanks, guys - the car is just gettting finished and tweeked in. I've been monitoring Hybrid Z for some time before joining - You have some serious technical resources here. Scottie, I'd really like to get together sometime - I bet I want to see your car at least as much as you do mine. I just built a turbo Buick motor for my brother's GN (he effortlessly runs deep in the 10s)and have tremendous respect for that thing. This is a poor excuse for a website, but more pictures are at http://rick.thebowersplace.com Got to get a proper website going.

Put me on the list of interested parties. I'm finalizing plans for an upgrade to a 60-1 from a T3/T4. I'll keep checking back for pricing and turbo compatibility .

Ihave a TEC2 on my 77ZT. I love it.The programming may seem intimidating at first but if you have a basic knowledge of fueling and timing, plus an AFR meter, you gain confidence fast.

I have the MSA 2-1/2" setup w/Dynomax on my '78 w/274deg. cam, worked,big valve e31 head,MSA Header,+.040 bore, Haltech & turbo injectors. Good performance & sound quality, Low price.