Aero and Suspension Tuning With True Type Coilovers

Hotrodz · 07-07-2019, 07:16 PM

Quote:

Originally Posted by Brendan

This may be the first time I rated a thread 5 stars un-ironically.

Thank you sir and you have been rep!

ValidusVentus · 09-10-2019, 11:10 AM

I'm a bit surprised there is this much discussion on this point but, yep, well known fact that if you remove some of the lever arm advantage the wheel has over the spring (go from bucket to coilover) then you need to reduce the spring rate to maintain the same wheel rate

.

I have a pretty effective Aeromotions 72" wing and a 2.75-3" splitter and run 20k/9k (rear coilover) with good results. I do run some rake but the ride height is only slightly lower than stock. Lots of front overhang with the splitter and Stillen front end limit me. I don't want to get outside the optimum travel ranges on the suspension anyway.

I saw a huge gain from installing the Trackspec hood vents; more than I expected. Already with a partially boxed 34 row oil cooler, it seems like adding the venting has dropped oil temps by at least 10F.

The next aero mod on the list is adding vertical air dams in front of the wheel arches -adds pressure on the top edges of the splitter, keeps front tires out of the airstream, reducing drag, and reduces wheel arch pressure -reducing lift and improving brake cooling flow, I hope- and splitter fences to box in the splitter ends to keep the air from rolling off the side.

AlWakRa · 09-10-2019, 12:23 PM

Quote:

Originally Posted by ValidusVentus

I have a pretty effective Aeromotions 72" wing and a 2.75-3" splitter and run 20k/9k (rear coilover) with good results. I do run some rake but the ride height is only slightly lower than stock. Lots of front overhang with the splitter and Stillen front end limit me. I don't want to get outside the optimum travel ranges on the suspension anyway.

This is the setup I am looking for, I have 21kg front 7kg rear, thinking about 9kg rear before I add aero parts.

Eagle · 07-08-2019, 01:31 PM

Quote:

Originally Posted by Hotrodz

So I have been doing some research on adding a rear diffuser to my current setup when I ran across an article/blog on the Professional Awesome Racing website https://professionalawesome.com. After read their article on aero and downforce I decide to shoot them an email to see if their splitter diffuser would be a good addition to my front aero. Long story longer we have exchange sever emails regarding my aero and suspension most significantly my spring rates and the owner Dan O'Donnell provide me with the following information:

So you have a “true type” rear, meaning the spring is directly on the damper body, not in the stock bucket. This has the effect of dramatically increasing the “wheel rate” or effective spring rate at the wheel, if you are using the same spring rate you use previously. If you are running 14k front 12k rear or 800lbs front 700lbs rear, the car will oversteer badly. I just had a long discussion with Savanna Little and Kevin Parlett. They are using a “true type” design as well on similar chassis designs and no suspension manufacture compensates properly for the change.

With your rear wing, I think you can safely add our diffusers and vents, but I would really, really want you to change spring rates to a proper setup. Your system is borderline unsafe in my opinion. Let me know if you want to do the calculations to get the right springs in there. Quick math is lettings me like if you have 14k front springs, you need to be around 5-6k in the rear.

So I am prepared to pay for the his consulting fee as this a steep learning curve for me and at my soon to be power level I don't want to be wadding my car up or possibly hurting anyone else. Here is where I need some help as he needs some information from me to dial the best spring rates for the rear coilovers. I need to provide him with corner weights for the car and obviously right now I have no way to do so. He doesn't need to have actual numbers but just need to be in the ballpark. My car weighs about 3440 with me in it and I am 210 lbs. If any of you have corner weight numbers and your car is of similar weight I would greatly appreciate you providing them to me.

Thank you in advance and go check out the Professional Awesome Racing!

Cheers,
Bob

Excellent thread Bob! The timing is just perfect for me since I'm just embarking on my journey into the realm of real aerodynamics. I'm pretty pleased with the splitter and canards i've got on the car now and after testing at Laguna Seca, I can definitely say that the aero was working. Cant wait for my wing to arrive. Need to read through the material on this site, seems like there's a lot of great info and guidance here. Thanks for sharing and im looking forward to hearing more about the development of your car with Professional Awesome Racing.

Hotrodz · 07-08-2019, 02:34 PM

Quote:

Originally Posted by Eagle

Excellent thread Bob! The timing is just perfect for me since I'm just embarking on my journey into the realm of real aerodynamics. I'm pretty pleased with the splitter and canards i've got on the car now and after testing at Laguna Seca, I can definitely say that the aero was working. Cant wait for my wing to arrive. Need to read through the material on this site, seems like there's a lot of great info and guidance here. Thanks for sharing and im looking forward to hearing more about the development of your car with Professional Awesome Racing.

Glad to hear things went well at Laguna Seca. A front splitter and lowering the car provides for better turn in and cornering grip for sure. Which wing did you get?

Eagle · 07-08-2019, 04:20 PM

Quote:

Originally Posted by Hotrodz

Glad to hear things went well at Laguna Seca. A front splitter and lowering the car provides for better turn in and cornering grip for sure. Which wing did you get?

I was expecting the car to be a little oversteery but turn in seemed to improve on the faster corners like turn 9 and 6. Corkscrew seemed to have gotten better as well, earlier on the throttle at the exit, flat out.

I'm getting the Ings +1 ZPower Ver. NISMO wing

Hotrodz · 07-08-2019, 05:05 PM

Quote:

Originally Posted by Eagle

I was expecting the car to be a little oversteery but turn in seemed to improve on the faster corners like turn 9 and 6. Corkscrew seemed to have gotten better as well, earlier on the throttle at the exit, flat out.

I'm getting the Ings +1 ZPower Ver. NISMO wing

Beautiful wing! You may have to make some adjustments when you add the wing because of the additional rear grip. It may simply add even more traction because your car is well balanced to begin with.

Sent from my SM-G965U using Tapatalk

03threefiftyz · 07-08-2019, 05:15 PM

I've done all these things...what is is specifically you are asking here? A lot goes into it beyond basic geometry and "aero"? Aero is a wide term...

Eagle · 07-08-2019, 06:20 PM

Quote:

Originally Posted by Hotrodz

Beautiful wing! You may have to make some adjustments when you add the wing because of the additional rear grip. It may simply add even more traction because your car is well balanced to begin with.

Sent from my SM-G965U using Tapatalk

Yeah i've been told that I may need to stiffen my coilovers a bit more and even go to a higher spring rate if necessary. We'll see once the wing gets here though. Also I completely forgot but i do have my corner balancing numbers for my car and it weighed in pretty close to yours. I'll post those up when i get home so you can compare.

Spooler · 07-08-2019, 07:56 PM

Quote:

Originally Posted by Eagle

I was expecting the car to be a little oversteery but turn in seemed to improve on the faster corners like turn 9 and 6. Corkscrew seemed to have gotten better as well, earlier on the throttle at the exit, flat out.

I'm getting the Ings +1 ZPower Ver. NISMO wing

That is actually a nice looking wing and I can't stand big Wangs….

Rusty · 07-08-2019, 09:38 PM

Quote:

Originally Posted by Spooler

That is actually a nice looking wing and I can't stand big Wangs….

You will end up with a wing.

Eagle · 07-09-2019, 01:54 PM

Quote:

Originally Posted by Spooler

That is actually a nice looking wing and I can't stand big Wangs….

Honestly, there aren't many wings out there that can claim that they've been track proven in a wheel to wheel racing series like Super Taikyu on the 370Z and 350Z platforms. I think CWEST is maybe the only other one but they never made anything for the Z34. It's definitely a nice kit, I'm considering replacing the end plates with something similar to the Singular pieces Hotrodz is running.

Spec Jay · 07-20-2019, 01:50 PM

Very interesting thread

If I remember right, SPL says that going from OEM bucket to true type increases effective spring rate by 1.66.

Currently running a custom front splitter with air dam with around +.5 degree AOA with 3" of protrusion. Rear wing is a Aeromotions 72" (DO NOT BUY. It works well but a **** company.) with 6 degreesl AOA. Spring rates are 14k F rear 12k in OEM bucket.

So if I went to a true type I'd need somewhere around 7.2kg springs to maintain the current balance.

Balance of the car is setup to understeer slightly right now. with a degree less in the wing it was almost perfectly balanced.

I was running these spring rates without aero and now with. I definitely feel that I could use a bit more rate purely going off my amateur seat of pants feel.

Here's SPL's spring size calculator but it's where I grabbed the info about the spring location modifier (spring motion ratio)
http://www.splparts.com/content/SpringCalculator.xls

Hotrodz · 07-20-2019, 03:03 PM

Quote:

Originally Posted by Spec Jay

Very interesting thread

If I remember right, SPL says that going from OEM bucket to true type increases effective spring rate by 1.66.

Currently running a custom front splitter with air dam with around +.5 degree AOA with 3" of protrusion. Rear wing is a Aeromotions 72" (DO NOT BUY. It works well but a **** company.) with 6 degreesl AOA. Spring rates are 14k F rear 12k in OEM bucket.

So if I went to a true type I'd need somewhere around 7.2kg springs to maintain the current balance.

Balance of the car is setup to be slightly neutral right now. with a degree less in the wing it was almost perfectly balanced.

I was running these spring rates without aero and now with. I definitely feel that I could use a bit more rate purely going off my amateur seat of pants feel.

Here's SPL's spring size calculator but it's where I grabbed the info about the spring location modifier (spring motion ratio)
http://www.splparts.com/content/SpringCalculator.xls

Thanks for the info as it is in line with much that has been posted. I am definitely running way to much rear wing for the my GT 300. I will be starting over as Daniel recommended: " Dial the center of the wing so the angle is actually more like -5 degrees to start with (with the front slightly higher than the rear of the wing), so it’s being used at its most efficient. Then, check for high speed understeer/oversteer and adjust from there.

If it has high speed understeer, lower the front of the car. If it has oversteer, maybe take the main plain of the wing to 0 degrees (parallel to the ground). If it still oversteers, raise the front of the car to reduce front down

I enjoy following you on Instagram!

Spec Jay · 07-20-2019, 05:44 PM

Quote:

Originally Posted by OptionZero

what fender vents?

they look a hell of alot like the 2020 GTR NISMO's...

I got it from a guy on instagram, username https://www.instagram.com/n00dler

Quote:

Originally Posted by Hotrodz

Thanks for the info as it is in line with much that has been posted. I am definitely running way to much rear wing for the my GT 300. I will be starting over as Daniel recommended: " Dial the center of the wing so the angle is actually more like -5 degrees to start with (with the front slightly higher than the rear of the wing), so it’s being used at its most efficient. Then, check for high speed understeer/oversteer and adjust from there.

If it has high speed understeer, lower the front of the car. If it has oversteer, maybe take the main plain of the wing to 0 degrees (parallel to the ground). If it still oversteers, raise the front of the car to reduce front down

I enjoy following you on Instagram!

I definitely have more wing than necessary too, mine is just one slot up from minimum. I need to redo my front splitter to make it protrude 5" and figure out a way to run some splitter diffusers so I can take better advantage of my wing.

https://professionalawesome.com/prod...iffusers-pair/

I like it balanced to have to slight understeer just cause it makes me a little more comfortable getting on the go pedal on corner exit. you may like it since you and I have more than enough power to correct understeer with go pedal haha.

Right now I have a 0.5" of rake. It made a huge difference from when I initially did the aero. Heres a before and after. Granted it's on the front straight but it gives a good visual about how suspension and aero settings work at balancing the car. Wing was set at the middle setting around 10 degrees front had a positive 3 or 4 on the splitterwithout the air dam and zero rake. Was terminally understeer heavy.

Thanks for the compliments!

09-10-2019, 11:10 AM	#2 (permalink)
ValidusVentus Enthusiast Member Join Date: Jun 2011 Location: Washington State Posts: 400 Drives: #18 Z34 Rep Power: 24	I'm a bit surprised there is this much discussion on this point but, yep, well known fact that if you remove some of the lever arm advantage the wheel has over the spring (go from bucket to coilover) then you need to reduce the spring rate to maintain the same wheel rate . I have a pretty effective Aeromotions 72" wing and a 2.75-3" splitter and run 20k/9k (rear coilover) with good results. I do run some rake but the ride height is only slightly lower than stock. Lots of front overhang with the splitter and Stillen front end limit me. I don't want to get outside the optimum travel ranges on the suspension anyway. I saw a huge gain from installing the Trackspec hood vents; more than I expected. Already with a partially boxed 34 row oil cooler, it seems like adding the venting has dropped oil temps by at least 10F. The next aero mod on the list is adding vertical air dams in front of the wheel arches -adds pressure on the top edges of the splitter, keeps front tires out of the airstream, reducing drag, and reduces wheel arch pressure -reducing lift and improving brake cooling flow, I hope- and splitter fences to box in the splitter ends to keep the air from rolling off the side. Eagle, Rusty, Hotrodz and 1 others like this. __________________ Mods: Dedicated caged track car, lots of things. \|\|\| Valkyrie Autosport \|\|\| Last edited by ValidusVentus; 09-15-2019 at 01:11 PM.

07-08-2019, 05:15 PM	#8 (permalink)
03threefiftyz Track Member Join Date: Apr 2010 Location: MD Posts: 536 Drives: 03 350z 6mt Rep Power: 17	I've done all these things...what is is specifically you are asking here? A lot goes into it beyond basic geometry and "aero"? Aero is a wide term... Hotrodz and Spooler like this.

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