jgkurz

Thanks Tony! I ended up buying a lower patch and graphed it in to the damaged area on my perfect original fender. I could not find a high quality used fender.

Hi all, I damaged the passenger fender on my low mileage 77 280z and am looking for a replacement. I am surprised how hard it is to find a good fender theses days. I remember when Z parts were plentiful. It it looks like those days have passed. I have heard that 240z and 280z fenders are not identical. Can anyone explain what the differences are, even if they are subtle?  Thank you, John

>>Yeah, more power on less boost is always good but the cost to do this project was crazy expensive. Having a part custom CNC'd on top of an expensive BB turbo added up to big $. The $/hp just didn't work out well. To some degree that is the nature of any car project. I like the car and it is fast so it's all good. >>I think the GTX hotside issue can be attributed to the Tial housing. Their .63 visually looked smaller than my T3/4 .63 housing. I should have taken that cue. >> I may test 27psi some day, but I will need to beef up my valve springs. My Crane springs are 90# at the seat so only 63# if I run 27psi. I think my peak RPM of 5400rpm may be caused by weak valve springs. That and a near stock head and N42 intake. >>I have learned this as well. A journal turbo from a quality manufacturer is still a great option. Thanks for all your comments!

Hi all, I finally got time to install the new .82 housing and dyno test. To close out this thread I wanted to post my results. The new Garrett GTX3576R finally was able to produce 467hp and 496ftlb on a DynoJet chassis dyno. The .63 housing maxed out at 404hp and just under 400ftlb. Boost was 23lbs. The boost lag worsened a fair amount with the larger housing. The boost did come up far smoother which was a positive effect. Also, the old turbo with the small turbine housing use to come up on boost quick which was fun, but it would also reek havoc on clutches. Here's the interesting thing about my upgrade. The old T3/4 hybrid made 451hp and 467ftlb at 27psi WITH a .63 turbine housing and quick spool. My new EXPENSIVE turbo did make more power at a lower boost, but was it worth it over a traditional T3/4 journal bearing? Not really. I started with a .63 housing on new GTX3576R, but it caused 10psi of back pressure and only made 402hp. The old turbo made 451hp with a .63 turbine. The 16hp gain with the GTX3576R wasn't worth the trouble given the boost lag. My cylinder head and intake are near stock which is certainly limiting my engine. Notice the peak power is at 5400rpm. All-in-all, 550hp at the crank is pretty good for an old L28.

Just spoke to Hitachi Automotive Systems@ 1-800-548-2549. They bought Tokico. To honor the lifetime warranty, they are giving me a full refund after I send the original receipt and struts in for inspection. Not ideal but I guess that will work. Now the question is...do I go Koni or Bilstein? Hmmmm

I know this is a very old post but I thought I'd add some new data. I finally dusted the cobwebs off the Z and did some back pressure testing. I changed to a new GTX3576R Gen I as stated above but went with a .63 turbine because I made 455whp in the past with a .63 and didn't want to sacrifice driveability. The new turbo couldn't muster more than 402whp which was disappointed to say the least. I have a custom adapter between my exhaust manifold and the turbo that I tapped for the back pressure fitting. I hooked up a DynoJet sensor on my intake and one on the newly tapped turbo adapter using a brake line as TimZ suggested. At 23.4psi gauge (262.75kpa) I was getting 33.78psi (334.29kpa) at the turbine inlet. The pressures started diverging at 3500rpm and got worse all the way to readline. In the end, I had 10psi worth of back pressure. WOW! I have ordered a new .82 turbine housing since that is the only possible restriction. My 3" mandrel exhaust is the same as before. One interesting side note. The GTX35 series turbos from Garret all have the exact same turbine wheel as mine and claim to support up to 1000hp (GTX3584R) The .63 turbine must be for a much different engine because it didn't work well for me. Also, the compressor on the GTX3576R must be moving a ton more air at lower boost vs my old t3/t4 hybrid to create such a restriction. The old L6 is flowing better than I thought. I hope to get back to the 450ish whp with the new turbine. I have seen the EVO and Subie crowd get almost 600whp with my turbo so 450-500 whp should be doable with the MUCH less efficient L6. Stay tuned..

It looks like Tokico is now owned by Hitachi. I will contact them regarding warranty replacement but I am not hopeful. http://www.hitachi-automotive.co.jp/en/products/shock/catalogue/

Yes, the downpipe needed to be completely re-fabricated. Like you, I hoped it would be a simple flange change but it was not in my case.

Not fixed yet. Ordered a .83 housing, but still while off from completing the install. I'll be sure to post results when I get the car back on the dyno.

Thanks for the offer. You are definitely close. If I can find a way to repair or replace a single strut, that would be ideal. If I have to replace both I’ll probably just go with the Koni adjustables.

Hi all, I have Tokico Illumina adjustable struts on my 77 280z. For a few months, I have been trying to figure out a mystery clunk in the rear of my car. Yesterday I finally found the problem. My right rear strut had failed and is clunking around in the strut tube. I know these struts are difficult if not impossible to find these days. The failed strut is pn BZ3013. What are my options? Does anybody sell these new or used? Can they be repaired? Thank you.

Hi all, Just a quick update. I finally got some time to work on this project and made an interesting discovery. I tapped my new adapter between the turbine and the exhaust manifold so I could test back pressure. I used the sensors from the DynoJet to log pre-turbine pressure and intake pressure. The pre-turbine sensor read a full 10psi higher than the intake. I have confirmed that back pressure due to my .63 a/r turbine is the issue. What I find interesting is that this new setup uses the same .63 a/r turbine size as the old t3/4 but makes a lot less power. It makes me wonder whether they really are the same even though on paper they are supposed to be. Maybe the combined T350 turbine wheel / .63 modified turbine housing on my old turbo flows more than the GTX3576R with the .63. Its really the only explanation I can think of. The question now is whether I should go to a .82 or 1.03. I’m sure a 1.03 would be great for peak power but would be miserable to drive on the street. I am leaning heavily towards a .82.

Thanks for the comments and re-assurance. The dyno chart is before and after (old turbo vs new turbo). Different dyno's but the same DynoJet model. The fact that the lines match up so perfectly at the starts leads me to believe the data is good. No other changes to the air flow of the engine other than a large 4" inlet to the turbo and a equally large K&N filter. The downpipe is new and all mandrel 3" like before. Here's a pic of the flange we made for the v-band and the new DP. I'll work on the AFR, boost, and timing graphs. P.S. How do you shove 34psi in a 10:1 engine on 93 octane? I know the EVO engines are state-of-the- art but the compression at 34psi would be about 18:1. Just curious how that is even accomplished. I have a friend who gets similar power out of Toyota MR2 engines. Simply astounding your engines stay together. P.S.S. I am pleased you are working on another Z project. I can't wait to see how it comes together.

I did a full leak-down and compression test recently just prior to the turbo upgrade. All cylinders checked out. I do need to check the plugs as well. I have ordered my new .82 housing and will report back as soon as it is installed and re-dyno'd.

Excellent info James. Thank you. That EVO has to be a handful at those power levels. It's amazing the drivetrain doesn't fly out of the car. You probably don't remember, but my car was built with much of your advice. You guided me through several build questions on email and over the phone. It's been a LONG time. I think you had your yellow 240 back then. The only thing I regret on my engine is my choice to run low compression. Oh well. I can just run more boost.

I read through the Perrin link again and it is interesting for sure. Notice the Dynapack dyno is showing flywheel HP and TQ which is different. I initially saw his GTX3582R with the .63 turbine housing reach 497hp so I figured I'd be able to make 455hp again with my old L28. WRONG! His 487 is flywheel. My 455 is rwhp so not the same. 487 crank hp will be in the neighborhood of 414rwhp if 15% drivetrain loss is used. The weird thing about my issue is that the new GTX3576R is worse all around, not just top end. If it was just worse at top end I'd be super confident that the .63 was the issue. I am going to try a .82 but I also may have boost leak issue that needs to be resolved although I have no idea where. On a postive note. if the .63 housing is indeed choking the HP as low 3000rpm there may be significant gains possible across the whole RPM range with the larger .82 housing. I call it pent up demand. Just a theory at this point.

Hi Bernardd, I have been stubborn about keeping the .63 due to spool but I think it's time to make the change. The dyno shop I work with wants to tap my exhaust manifold to check back pressure, which would prove all this scientifically, but that adds even more cost and time. My turbine is a Tial v-band setup. Is that what JeffP uses? I have not checked my BOV and WG because they seemed to be working as they should. My Tial 44mm wastegate has springs that put me at 13psi with the boost controller off. It is controlling boost well until 22psi. I am bleeding boost after the "stonewall" occurrs. Boost is super stable until then. How would I check my BOV? Just increase BOV spring pressure and run it up to max boost again?

Thanks for the the link from 2009. It certainly seems to apply here. I even commented haha. I think I'm going to swap in a .82 exhaust turbine after I check for the obvious issues. I was worried about spool so I went with the .63. My guess is that the new (larger) compressor is choked earlier than I expected. Looking at the dyno graphs, the engine goes worse as early as 3K RPM. My hope is that the .82 get's me back to my older dyno results plus a bit better.

I have read parts of that article in the past. It is an excellent piece. It's amazing that a street 4-cyl can support a GTX3582R.

The 27psi was with my old turbo. The new turbo hit a wall after 22psi. I tried higher than 22psi but it made no more more and boost would drop back top 22psi again. Changing the Tial v-band turbine housing from a .63 to a .82 might be worth a try but it will cost me ~450.00. That's a lot better than a new turbo I guess. I could sell my .63 for 150-200.00 or so which would help.

Awesome stuff seattlejester. Thank you for thinking about this with me. My old turbo did not have any anti-surge ports or any surge issues that I could notice. It would jump up to 27psi without too much issue. 27psi was the limit as I was clearly going outside the map on the right at that point. The new turbo does have anti-surge so if I am surging I am not hearing it.

I really debated between the GTX3076R and the GTX3576R. I thought my engine could support the GTX3576R based on some basic compressor map plotting and my previous dyno results. My intercooler outlet pipes are all 3". The inlet pipes are 2.5" which match the turbo outlet. The intercooler itself is large and seems to be working well based on inlet/outlet heat tests and previous power levels. I've never done a pressure differential test. I will be verifying some basic things like, throttle opening, turbo damage, air cleaner flow and such before I do anything too radical.

Gollum, Thanks for putting thought into this. Here are the specs to my car: http://fstrnu.net/z/specs.htm I went with the GTX3576R because I thought the GT35R (or the newest version GTX3582R) would be too big. Several Turbo L28 folks run the GT35R with great success. I went smaller than the GT35R, but larger than my old turbo for the exact reasons you mentioned. I wanted to be well inside the surge line. I did the math a while back to plot my compressor map. I will do it again now that I have real world dyno info. I sure hope you are wrong. Other than low compression, the biggest issue with my setup is the intake, head, and exhaust manifold. It would take big $$$ to fix all that properly. The goal of the project was not more peak power, but a more efficient turbo so I could run more power under curve on pump gas. I didn't think for one second I would be going backwards since my old turbo was a such a terrible design, at least on paper.

Circling back to this thread. I've been working with some people a lot smarter than me and have learned a few things. My GTX3576R is larger than my old turbo in all respects. Garrett claims it will support 600RWHP. Even if that's optimistic, 500RWHP should be possible on a well built/tuned engine. Notice in the below dyno comparison that the GTX3576R (red lines) fell off significantly starting at 4000rpm and was negative at 3000rpm. The old turbo is represented by the blue lines. I have been focused on exhaust pressure and the turbine housing size. Based on the dyno chart, the experts I mentioned above believe the issue is on the intake side air flow. I'm surprised by this since everything is the same as the old turbo, but with a MUCH larger turbo inlet and K&N air cleaner. The investigation continues.

Yes, on the dyno I always like to use race gas for the safety factor. Cheap insurance. I can safely run 15psi on 92 octane. My recent coolant bypass on cyl 4,5,&6 seems to have helped keep the head much cooler.