jgkurz
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Posts posted by jgkurz
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The car is on the street most of it's life. I occasionally participate in track days, autocross, and even drag racing on a rare occasion. If I find my self doing more track days I'll add more neg camber. The caster @ 3.5deg is already getting close to my front fender. I might be able to get to 4deg but that's probably the max.
How much neg camber would you run for a car like mine that sees both street and track time? Just curious.
This weekend I have been invited to a drift event which will be entirely new for me. I will probably be the oldest one there at 50. Ha! I don't plan on ragging on my car too much but I might enjoy sliding around a bit with some friends and family doing the same. I need new tires anyways so I figured why not give it a try.
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I upgraded to adjustable lower control arms and was able to fix the rear toe. Below are the new alignment specs. Drives and steers much better. Thank you for all the help on this one. Can't wait to get it to the track for some real testing.
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Thanks for the info. I just ordered the carbon fiber spook spoiler for my 280z. Thanks for the BRE tip. I didn't even know they still existed.
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Hi all,
I would like to add a chin spoiler to my 77 280z. I am looking at the BRE ducted style from various suppliers. These spoilers simply bolt on to the lower valence. What I am trying to understand is if lower part of a 240z valence is different than a 280z valence. I sure would like the carbon fiber version from MSA but I need to make sure it would bolt up before I buy. I know the description says 240z and 260z only, but visually I have never could see why it would not bolt to a 280z the lower valence .
Are they really that different?
240Z Version
280Z Version
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On 7/26/2018 at 9:45 PM, Leon said:
In a vacuum, both toe-in or toe-out would cause dartiness as single-wheel inputs will steer the car one way or the other. I also don't agree with toe-out being better for turn-in, as it decreases your yaw rate gain, i.e. you need more steering input per given corner radius.
Now if we take ourselves out of the vacuum, there are other effects that influence static toe settings such as suspension compliance (mostly controlled by bushings) and kinematics (bump-steer). I haven't seen any published K&C test results on an S30 chassis but if you've installed poly bushings everywhere, keeping toe close to zero with a dab of toe-in, as you have it, is a safe bet.
The cheapest way of adjusting rear toe with stock arms is eccentric bushings. I've never used them but I don't see any other way around that other than adjustable arms or doing a bunch of fab work to slot the transverse link supports and splice in a turnbuckle into the transverse link brace (this has been done and can be found by searching).
I bit the bullet and ordered some Techno Toys rear arms and tie rod ends. I hope to have them installed so. I am also considering going back to stock steering knuckles. My car sees about 50% street duty so it might make the car more enjoyable to drive around town. Remind me, what rear toe should I put on the rear arms if I'm going with slight toe-in on the front?
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29 minutes ago, Zipper said:
jgkurz - You mention 'dartiness', also lowering springs and bump steer spacers. Have you considered bump steer? Hybridz bumpsteer-faq
Not a suspension expert - but I experienced a big improvement in handling feel with similar mods to you after changing to adjustable tie rods. On alignment rack, toe changes were obvious by ratcheting suspension down/jacking up. Was able to tune a lot out with adjustable tie rods. Bigger tires, quick steering arms, and a smaller steering wheel contribute to heavy steering feel.
Do you have a link to the adjustable tie-rod ends you used?
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8 hours ago, Leon said:
Higher caster should have more of a centering effect due to the increased trail which increases the aligning moment on the tire. The caveat is that with the steering geometry of the Z (including but not limited to), there's a point where steering forces reverse and there is a wind-on effect where the wheel steers itself towards lock. This is all a long-winded way of saying that bringing caster back down will not improve your return to center problem and that return to center will suck no matter what, when you reach a certain critical steering angle. However, I haven't studied the Z's geometry that carefully so I very well could have overlooked something.
Adding more front toe will make the car dartier, that looks good where it is. The added negative camber may make the car dart a bit more but it's a smaller effect than toe.
I really think that rear toe is doing you wrong plus maybe some other mechanical factor that we haven't found yet. Have you checked your steering system for slop (ball joints, rack, etc.)?
I have checked the car thoroughly but I could have missed something. If a better mount or bushing was available I have upgraded it.
Back to the toe conversation. My understanding is the toe-out in the front would cause more dartiness but better turn-in at the track. Toe-in minimizes the dartiness/tramlining affect especially on the freeway. Is that not true?
Regarding rear toe, any suggestions on reducing toe-in with stock lower control arms? I could loosen up the mounts and try to tighten the LCA's while prying on them.
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5 hours ago, HuD 91gt said:
A bit of a tangent, but you bring up your sway bar was too tight. I’ve yet to read a proper way to tighten sway bar bushings.
The bar should rotate smoothly in the frame bushings. It should not catch or have stiction at any point. I added shims to each mount so when I tightened the bolts, the urethane clamped the bar snuggly but no so tight the bar could not move. I also used a lubricant meant for sway bar bushings.
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11 minutes ago, Leon said:
Strange, I wouldn't expect steering feel to dull after increasing caster/trail.
It comes down to what you mean by dull steering feel. Is it the steering feedback that's dull or a lack of body rotation per steering input? To me, it sounds like the latter and should be helped by reducing your rear toe. A huge front bar and no rear also doesn't help.
Leon, thank you for the comments. I drove the car again tonight. The return to center is worse as well so that's another symptom. It's a little darty if that makes sense. It's slight but noticeable. I think the combination of additional steering effort + lack of RTC + dartyness make the car less fun to drive. It may be better at the track but it's a hotmess on the street. I may go back to stock caster and add a bit more toe-in and see if that helps. 1/40" toe-in is probably not enough. I can't fix the rear alignment until I get adj LCA's.
I do have a 3/4" rear bar. I should have included that in my first post.
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4 hours ago, Leon said:
That's a lot of rear toe. I would dial that back to no more than 0.10° per side. Do you have your previous alignment specs to compare to?
Yeah, I need to get the rear alignment sorted out. I also should go to coil overs, stiffer springs, camber plates, 1in front sway, and adjustable rear LCA's. 😫
After reading all your responses and talking to some experts I think the car is acting properly. The additional steering effort is a combination of the quick ratio steering arms and the extra caster. The dull steering is probably because the suspension is actually working now and not artificially stiffened by the sway bar stiction.
Below is the old alignment where the front sway bar was too tight.
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2 hours ago, JMortensen said:
Not seeing anything that would cause a dead feeling in the wheel, but IMO that alignment is short on neg camber in front and heavy on toe in in the back for track use.
I am not a fan of the 1 1/8" bars, would swap for 1" if I were you. You don't mention a rear bar, but with lowering springs I would run a 1" front and the ST rear bar that attaches to the uprights, and then shim it back 1/2 to 1", whatever fits best.
Removing stiction from the sway bar bushing may make the suspension less stiff, but it also makes it smoother which means that the sway bar will resist in a constant way, rather than resist/release/resist/release, etc. When I built my suspension I went to great lengths to eliminate stiction in every way I could, as that makes the car more consistent and allows the suspension to work, and the wheels to follow the pavement better in bumpy turns.Good stuff Jon. Thank you. I agree that the elimination of stiction probably is now allowing my suspension to work properly. My car does occasional street duty which is why I only went with -1.3 camber in the front. The rear control arms are all stock and non-adjustable so I'm stuck with those specs until I upgrade. I probably now also need stiffer springs to dial in the car. For the rear sway bay, I use a 3/4" 240z style rear bar mounted to the uprights. My 280z bar rubbed my CV boots so I switched styles.
What do you mean by "shim it back 1/2 to 1", whatever fits best."?
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Thank you LLave. I have read John Coffey's post which was the starting point for my alignment. I just didn't end up liking the end result. Certainly my car is the issue so I'm curious what to try if I modify the car and align again.
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Hi All, I need some perspective on my front end alignment. I recently installed adjustable lower control arms and TC rods and got the car aligned with specs I thought would be more suitable for track days at my local road racing venue. I don't think my specs are radical by any means, but after the alignment the steering is harder to turn and dull. I went with slight toe-in to avoiding tram-lining aka wandering on the freeway. 0.06 deg toe-in on each side = 1/38" so very slight. I have all the typical novice suspension upgrades including bump steer spacers, quick ratio steering arms, and urethane everywhere. My tires are 225/50-16 and 245/45-16. I also have lowering springs and Tokico adj struts that bring the car down about 1.5" from stock. My front sway bar is a Suspension Techniques 1-1/8" with the typical urethane bushings. Before the upgrade the two frame mounts for the sway bar were super tight and near locked. To resolve I shimmed the mounts so the bar moves freely now but without play. The previous alignment with the stock LCAs and TCs seemed to be sharper and more responsive which is disappointing considering the upgrades I just added. Maybe the sway bar moving properly softened up the suspension which caused my previous setup to be artificially stiff and more responsive albeit incorrectly? I'm just guessing at this point.
My question. Is the more difficult and dull steering feel to be expected with the additional caster and neg camber? Are there any glaring issues that would be causing these symptoms?
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32 minutes ago, turbogrill said:
The link doesnt work for me.
The site seems to be working for me and other people I have asked to test. There is some security that might block access from outside the USA. From your signature it looks like you are in TX. PM me if you want to troubleshoot.
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20 minutes ago, seattlejester said:
Welcome back!
Very nice adapter, looks much better than the pedestal with the flange directly off of it style. I'll be referring people to this for people looking for an external wastegate on the stock manifold.
I agree. The pedestal adapter you mentioned was never may favorite. If anyone wants to buy my adapter they should talk to Kris @ KO Racing. http://www.koracing.net/. Mine was the prototype, but he could make more if the desire was there.
Anyone looking at a project like this should know it's not cheap. Each build is different so I won't be providing my costs. I say this only to set the proper expectations. For me, the price was worth the results. If you want big power for a low price, best to look elsewhere.
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11 minutes ago, SleeperZ said:
Well, I run my L28 at only 300whp, so yours is beastly by comparison
Ha! Thank you.
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1 hour ago, SleeperZ said:
Welcome back, that setup looks beastly, very well done.
I'm not sure about beastly, but it does scare me when the boost comes on (in a good way). In the time I have been gone, it seems the L6 has become even more obsolete. I have no regrets about my old school engine, but my power levels are kids play compared to what can be had with a RB, 2JZ, or LS. In some ways I'm a little nervous about putting my L6 on FULL TILT with parts becoming more difficult to find. Blowing up an RB might actually be cheaper to rebuild than an L6 these days. An RB needs very little customization to reliably make my power where my L6 needs massive work.
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59 minutes ago, turbogrill said:
Nice! Could you tell us more about the car?
What head and pistons? What intercooler?
Do you track it? Any heat issues?
Thank you turbogrill. Most everything you want to know is in the link I provided in the original post. http://fstrnu.net/z/
Let me know if you have specific questions.
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3 hours ago, rossman said:
Welcome back! The new turbo and turbo setup looks pretty slick. I like the way you integrated the adapter with the wastegate port - all of the angles look like they will flow well. I have a GT3576R (pre X model) with a .63 A/R turbine and seems to work well with my engine. I'm sure the X version would perform even better.
Thank you rossman. Garrett now has a GTX Gen II out so maybe it's even better than my Gen I. My Gen I is working well enough that I don't know what I would upgrade to even if I wanted to. Any more power and I'd have to re-do the whole fuel system.
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It's been a long time since I've posted anything of significance at HybridZ. I took my Z apart for a turbo upgrade in 2012 then in the middle of the project my wife and I decided to move. After getting settled into the new house, I got distracted with other projects and just never found the time to finish the turbo upgrade. About a year ago found a local tuner/fabricator that was interested in helping me get my Z back on the road. He was mostly a Toyota expert, but he was a superb fabricator and did quality work so I hired him for the project. The turbo I chose was a GTX3576R with a .63 turbine. I heard from a few friends that they thought this turbo was too small, but so far it seems perfect. My old turbo was a T4/T3 hybrid that made 455 rwhp. At that power it was well out of the compressor efficiency map. I wanted a more modern turbo that would improve power under curve and a maybe bit more peak power. All with less boost. Reducing turbo lag was may main goal. I could write a book on the project so I will try to keep it short.
Here's a bit about the car as it was in 2012. http://fstrnu.net/z/
The new turbo external size was a bit larger than the T4/T3. I need to find a way to fit it on the original L28ET manifold in addition to adding an external wastegate. The answer was an adapter that used v-band fittings for both the turbine and the wastegate. The below picture was a test fit so you can see the design aspects. The adapter was designed in Solidworks then CnC'd from a brick of steel.
Here's a picture before the downpipe was installed. I ceramic coated the adapter, manifold and downpipe.
Here's a picture with everything installed.
This is the engine as it is today. I added a coolant bypass on cyl 4,5,6 and I added an IAC for idle control. I also removed the AC since I never really needed it and the compressor got in the way of my air cleaner. Oh and the wiring has been tidy'd up since this photo.
Overall I could not be happier with the project. The new turbo and the various components have made a big difference in the turbo lag and bottom/mid range power. The car was fast before (11.30 @ 124mph), but it is even better now. I can't wait to get it back to the track for some fun. It's good to be back.
-John
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FWIW, I called and left a message at Lonewolf but have yet to get a return call.
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John,
The OEM exhaust manifold is creating quite an exhaust restriction. Your leaving a lot of flow on the table. It's well work the $ to have it ported. It's not that hard to do yourself. At a minimum focus on where runners 1,2,3 and 4 come together. Or send your manifold to these guys:
Thank a lot Tim... Now I have to spend money on porting. Ugh... : ) In all seriousness, Lonewolf looks like they are the "Easy Button" for porting. I'll probably pay more to ship them the parts.
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Each of you make a compelling argument for your turbine housing of choice. Thank you for taking the time to offer such thorough responses. It's great to be back on the forum and see everyone is still here.
The design of the new Tial housing makes them very easy to change out so I can easily swap if I don't like the first housing. I have an OEM exhaust manifold so maybe the .63 is still the way to go. I have never had the .82 so I'm curious how it works with my set up. In the end it may come down to personal preference. -
Tony and Skirkland180, I didn't remember that Jeff was using a .63 until you reminded me. It almost defies physics that he gets that much power out of that housing. I have done a fair bit of research and most say above 450ish crank hp the .63 is too small. Of course Jeff has proven that wrong. My car tips over around 5800-6000 but pulls like a freight train to that RPM. My last trip to the drag strip netted an 11.3@123.9mph with a 1.76 60ft on street tires so no slouch. I have an Isky cam that is only 480/490 lift with a 114 lobe center. I forget the duration. It should pull well past 6K but doesn't for some reason. My head is mildly ported and I have mandrel 3" exhaust. I'm going to give the new v-band Tial turbine housings a try in addition to a much improved wastegate and downpipe design. My hope is that the .82 won't hurt me too much on the bottom end and but solve my peak RPM issue. I may also install better valve springs. Mine aren't stock but I don't remember the spring rate.
The design of the new Tial housing makes them very easy to change out so I can easily swap if I don't like the first housing. I have an OEM exhaust manifold so maybe the .63 is still the way to go. I have never had the .82 so I'm curious how it works with my set up. In the end it may come down to personal preference.
Turbine size matters
in Turbo / Supercharger
Posted · Edited by jgkurz
Hi all, I had an interesting result on the dyno recently. Years ago I made 455 rwhp @ 27psi boost with my old non-ball bearing customized T4/T3 hybrid. It had a small .50 compressor housing with a 3" inlet and what Innovative called a GT58 wheel. The hot side was a T350 stage V wheel with a .63 housing. I recently upgraded to a very expensive dual ball bearing GTX3576R with a 4" inlet and a Tial vband .63 housing. Nothing else changed on the engine. I like the quick spool so I stuck with a .63 turbine housing. The new turbo made 366rwhp and was done at ~22psi. Adding more boost did not raise HP. That is a 89hp difference. On a modern engine like in an EVO or STI, my GTX3576R turbo could support close to 600HP. Obviously my old L6 can't flow enough air. What I learned is that the old turbine wheel has a 71mm Inducer/62mm Exducer @ 76 trim. The GTX3576R turbine wheel has a 68mm Inducer/62.3 Exducer @ 84 trim so a bit smaller. Another interesting point is that the new ball bearing turbo had a mirror image dyno curve to my new turbo up to 4500rpm or so. The myth that a ball bearing turbo spools sooner is not true, at least with my engine.
I am amazed that the slightly smaller turbine wheel caused the 73HP drop. I may try a .82 housing and see if that helps although I am confident it will add turbo lag.
-John