AydinZ71

I got one I traded my L28et manifolds, turbo, IC, IC piping and custom 3" downpipe.

@jhm thank you, sir! Update: ACP in Penn. is making me a Stahl style header. Greg was keen on not skimping on this part. Also got me an ATI damper and all parts for the front suspension are in hand: - Apex s130 low-profile adjustable tie-rods (steering). Starts at 3/4”+ track on S30 - John’s OEM LCA mod with adjustable track - Futofab TC rods - GC coilover w/sectioned OEM struts. GC bolt-on camber plates - Koni 8610’s questions: 1) anyone run a racing/lightweight alternator? Greg uses Li batteries w/o alt., and just charges the batteries after the race. I don’t think I’m there yet, so looking for a compromise. I found this. Eager for your feedback! 2) looking into AIM dash loggers. Anyone run these or have any preferences? PS: mocking up the pedal assembly

thanks! yeah man… it’s a frickin jigsaw puzzle, LOL 😂 Just finishing up a few structural pieces before I mock-up the Tilton pedal assembly. OEM holes were not going to work, so I just started with fresh steel.

More progress. Getting there! Starting to finally see the light at the end of the tunnel. Floor pan is ready for the seat mount crossmembers, then I can mock-up the tilton pedal assembly. I also ordered the Stahl style header from ACP per Greg’s recommendation. Also have all the front suspension components in hand. IMG_6504.MP4

That makes a lot of sense! Yeah watching several of the GoPro vids Greg was gracious enough to send me, I’m learning his driving style and how it relates to how his car is set up. You are spot on about him being the inspiration for removing my rear bar. I have stiffened the heck out of the front subframe and rockers (mostly in service of rust replacement). Have not stiffened the rear all that much besides the welded tower braces, cage terminal on towers, and connecting the floor pan stiffener through to the rear forward LCA cross member. We’ll see! Greg is building an new car for Vintage btw.

I have always wanted to know how a car felt between the two options: heavy springs with no rear sway bar vs. light springs with a rear sway bar. Let ya know how you like it!

Clean work man! Very impressed. Great job! Doesn’t seem like you got any heat warpage. A real accomplishment on rotsun steel.

Looking good! I think the K24 setups in a Z is a great option honestly. Great power with light weight. @heyitsrama this specific section of the subframe does not flex a whole bunch under torque. The nearby tie rod mounting box is the thickest steel on a Z. If it does bind, if blame steeper angle on the steering linkage. Ask me how I know so much about the subframe 🤣😂. I have rebuilt this whole section of the car in new steel. you do make a good point though, the whole subframe should be reinforced and/or a roll cage added for rigidity. Looks like this setup will produce at least 300ft-lbs which is where I feel the stock frame starts to flex too much.

Drivers side rocker rebuild+reinforcement almost done. Drivers side floor pan in. Next will be the drivers side subframe support through to the front crossmember. IMG_6432.MP4

Very cool brace lots of work! fascinating solution on your exhaust! I assume you went over vs. under because of ground clearance. Never seen that before. How much longer do you think you have before she is ready for prime time?

I don’t think it will warp too bad… There is quite a bit of steel (albeit thin) on both the scoop and the fender mounting surface. As always, go ultra slow. I doubt you could fit the gap with just steel alone unless you make many super slow passes. If you try to fill it outright, it will warp. I would do a single pass, grind, and finish with filler.

@JMortensen @clarkspeed Thanks guys! everything you say makes sense. Basically, figure out your extreme thresholds, and work your way into a "sweet spot". It clearly will not be near the extremes, but you don't know if it will be 60/40% until you work your way to the center. Thanks for the advice!! That should get my camber, and tire pressure dialed in. Il have to do more research on setting my roll-center. I am certainly not a consistent driver, so the tuning will improve as my driving improves as well. Yeah I told Greg i was looking at steel 10lbs unit. He was like "HA!, I just saved you 20 seconds on your lap time." I got the auto-trans flex-plate and spacer too, but still working on the chassis until I get this thrown on... Also, I am settling on the Apex tie rods (steering). Its the last suspension part I need. I lied...I still need to dial in RC, but those are just spacers. I have a 1" front sway bar and plan to run none in the rear. We'll see how it goes!

You have a lift!? Jealous!

Glad you were able to get it in Can’t you just move the exhaust a bit? Do you weld? you can hack that little corner off, but the vibration may still cause the exhaust to hit it. Use a cut-off wheel, and go slow so you don’t cook your gasket. Time will tell. Good luck!!

appreciate it Clark! Il try some YouTube vids. Greg has been super gracious to help, but I don’t want to bury him with questions I can have answered elsewhere. in other news, look what I just got in the mail. Surprise! This assembly has got to be less than 8lbs.

sorry friend. Plans have changed a bit so it may be another 4-6 months before the head is available.

thanks Jon! Super helpful apologize on goofing your name! In hindsight I have addressed you as Jon already so not sure what I was thinking. Il look for holes in my welding mask 😂 I got the rear’s fixed by re-sectioning them and adding the length. You were super helpful on that! on the fronts, looks like il just be making sure the coilover sleeve does not extend above the gland nut. Got it! any suggestions in an adjustable outer tie rod? I fabricated my own LCA’s (thanks @jhm) (previous post) and have purchased the Futofab adjustable TC rods. I’m on the fence on the outer tire rod. Either going with apex (not bad for $215), or fabricating my own with a left/right thread coupling nut or double-adjuster rod.

LOL! Love that episode! I just meant in case he was having trouble reaching them via e-mail, Facebook, etc

Hey Jim, et al. I am about to section my front struts and want to get this right. Do you, or anyone else know if I need to add 2" to the strut tube in the front as well? The dimension provided by GC from the bottom of the tube to the new coilover lower perch is 5" (rear was 7"). Also, if I add length to the front strut as well and use a spacer in the tube like I did in the back, doesn't this also act similar to the bump-steer/RC spacer? PS: I think I answered my own question: NO. Making the strut longer still moves the wheel hub lower. In order to correct RC, you need to increase the vertical gap between the wheel hub and the LCA, giving the arm a greater angle. -Aydin

I called them (number on their website) and asked some questions about their tie-rods last week. They picked up on my first try. Have you tried giving them a call? Just a thought. PS: I am not implying you did not call them.

I got one LCA modified. It looks like a phallic spaceship. Thanks again for everyone’s help on this!

Race cars require the vent to be piped to a catch cab, but the vent usually has a baffle that prevents oil condensate from leaking out in normal use. It important to allow the case to be ventilated at all times since the gas space will expand and contract as it warms/cools. If you really wanted to route the vent, you could just “pop” off the hat on the vent and put a hose on the ~1/2” long nozzle that remains with a hose clamp.

Yeah that is an R200. I would send it out for sanblasting. Quite a bit of rust/scale. Weld-in replacement metal with a MIG and grind flush if its really bad. When you get the axle shafts, they may come with the stub-shafts that go into the diff. Most people unfamiliar with these diffs do not realize those stubs slide-in and "click" with circlips. Therefore, those stubs shafts you see there can pull out with a hard "tug", and you can just slide in the whole axle with the stub shaft attached. Push them in until they "click".

@Sideways Best place to start would be “maximum boost” by corky bell (if you have not already) you will learn that there are significant inertial forces on the rods that increase exponentially with RPM, irrespective of torque. Then… there is torque. The stock rods can handle a TON of torque at low rpm’s precisely because they have so much material and are heavy. Most folks with L28et’s go for more torque than power so they let off at lower RPM’s. That’s because the P90 head doesn’t flow all that much air compared to modern heads, so she naturally falls flat over 5k under heavy boost. At these lower RPM’s (3-5k) the stock rods can can handle well over 400 ft-lbs in my experience. Not enough experience for me to say above 500 ft-lbs. back to the inertial forces, the heavy stock rods hurt you here. Piggybacking on Greg Ira’s experience with SCCA EP built motors, he sees the rods being a weakness above 8000 rpm due to inertial forces. Keep In mind, we’re talking an NA 2.4L race motor with no more than 170 ft-lbs of torque. These are the inherent forces due yo rapid acceleration of the rod (up-down). Hence, a more modern rod that is equally “strong” under torque yet lighter than OEM will overall handle a lot more power (which is a matter of torque X rpm). so yo answer your question fully, I’d say this: if you are building a conventional L28et with a bigger torque number than power, you could probably stretch the envelope above 400 and who knows… maybe 500 ft-lbs, with stock rods. I wouldn’t personally… but I can’t say it would fail for sure. however, if you want to make real power which requires moving that torque band HIGHER on the RPM band, definitely go with modern, efficient rods. That’s my plan. Pauter is a great rod vendor here in Socal. They have a “lightweight” L28 rod for NA racing application with light torque, and their standard improved rod which will handle a ton of torque but is still lighter than OEM. I got a quote recently at $1,500 for a full set for either option. Give them a call and tell them about your needs. They know what they are doing.

@tube80z hey that’s super helpful! Thank you! It’s tough to find the “right” book. I’m just looking for a general book on race car chassis and suspension dynamics based on empirical data more than theory. I have an engineering background so I got the theory part covered. Il definitely take the suggestions you provided! Doesn’t look like the book I found is right for me. thanks again for your help!