QUESTION: P2M Front Lower Tie Brace Install

Andrew's Z

Hey Z Friends,

I purchased the 370Z Front Lower Tie Bar (P2-FLTB370Z-SRE) and I am wondering if anyone else has purchased and installed this product.

The reason for this is, it looks like the suspension member sub stays need to be removed, and I would like to understand the performance impacts of removing these braces.

If this product was designed to increase rigidity of suspension why would I want to remove additional bracing which could compromise the rigidity of the connection to the subframe?

Would really appreciate some performance related input for all of you. I'd like to ensure I understand the implications of removing the suspension member sub stay. See image below of the OEM part impacted as a result of this installation.

Thank you as always!

Attached Images

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	thumbnail_image (1).jpg (64.3 KB, 21 views)

Tractionless

I'm not an engineer but that brace looks like useless redundancy to the lateral portion of the OE subframe right in front of the cat brackets. The lateral braces I see most use in the center of the chassis are rearward of the cats where there's zero OE reinforcement.

Additionally, I checked out the "suspension member stay" on my Z and would be hesitant to remove those as they appear to be providing rigidity to the unibody. FWIW, the aforementioned aftermarket lateral braces typically have extensions beyond the frame rails to the unibody just like Nissan does with the suspension member stay.

Check out the 4th pic in this link of a more substantial brace in the same position that retains the suspension member stay feature via the brace itself. They have other options for that areas as well but all appear to retain the suspension member stays in one form or another.
https://www.soulfunction.com/product...nt=37390503118

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ZoomZ

This is what I installed along with the 4 point member.

https://www.soulfunction.com/collect...533931#content

The 2 Short pieces replace the OEM "Suspension member stay" that you are removing.

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Andrew's Z

Thank you for all your input everyone and the alternative recommendations!

I reached out to P2M directly and they provided the response below, for those that might be in the same predicament as me. FYI

------------RESPONSE-------------
That’s for reaching out, you brought out a VERY GOOD VALID question.

Let me explain that all front lower tie brace (other names: front ladder brace, under brace, front subframe lateral brace etc.) main purpose is to “box in” the front cross member to the left and right main frame of the chassis.

If you look carefully at the front subframe, almost all vehicles are the same, *where front subframe runs laterally across left and right side of the main frame.* This is where the engine is positioned with engine mounts etc.* The purpose of front lower brace is to add additional reinforcement of the left and right main frame where front cross member bolts to, in a way it’s like adding 2 lateral braces to the front left/right main frame (one being the front subframe, and 2nd*one with the front lower tie bar) .* You can call this a double bracing of the front left and right main frame, or you can call it a box “H” brace to the front.* Regardless, by adding the front lower brace, it will help to reinforce the front frame just like adding on a front strut bar on top of the engine bay (front strut bar helps reinforce the top, front lower tie bar helps to reinforce the front end bottom).

Now, the side stay brackets that were removed, the test car that was used when developing the front lower tie bar over 10 yrs ago was rusted down severely.* Our tech side also determined that the position of the side stay brackets do not do much to the reinforcement of the front frame compared to running the front lower tie brace. It is works minimally well *for Nissan to make these cheap side stays than to make a full brace for cost reasons.* Not saying the side stay doesn’t work, they work so minimal there is no harm in removing the side stays and replace with front lower tie brace which will yield you much greater improvements.* For anyone removing the side stay brackets even without installing the front lower tie bar, you won’t feel any difference in performance handling.

So, to answer your question, in our view (our opionion), those side stay brackets are useless and you’re better off replacing with our front lower tie bar.
*
Wayne
P2M – Customer Relation
Phase 2 Motortrend Inc
14275 Albers Way
Chino CA 91710

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ZoomZ

Thank you Andrew for the research.

My take on the suspension member stay, is that it is transferring loads from the vehicle body to subframe. Then again, it could be doing the opposite as well.

Seeing that the subrame is much stiffer, I can only guess it is to prevent body flex and to transfer load to subframe.

The SF 6 point brace, takes it one step further, by extending that load transfer further aft and keeping a continuous, 1 piece member without any breaks or gaps. Resulting in a much stiffer set up.

Why did Nissan put it in? I agree that it was a cheaper, and easier set up at the assembly line (and for future maintenance). Otherwise, I think they would have to extend the subframe.

Why didn't Nissan just leave it out? If there is minimal torsion, flex, body roll, whatever you wan to call it. From my understanding, Nissan is building these cars for the street, not the track. So the objective is driver and passenger comfort first, track and sport secondary.

So, I think Nissan felt that there was some sort of uncomfortable feeling/ride or perhaps, a long term detrimental affect to body and frame.

I'll buy point number 1, as Nissan's cheaper alternative to a full subframe. Not point 2, as not needed.

I'm not an engineer, just what I observe.

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Andrew's Z

I agree with you ZoomZ. If Nissan's engineering team didn't think these sub stays served any purpose they would have opted to remove them and offer a cost savings in production.

Since they didn't do this, this tells me they serve a given purpose which outweighed the additional cost of producing and installing them.

Removing them without some sort of replacement is not something I am comfortable doing and will be looking at alternatives replacement to factory sub stays.

My concern now is I have this P2M part that may be useless to me as I don't think any alternatives will work with it -.-

I have let P2M know about this thread, hoping to see an official reply from there here as well for all your benefit.

More to come...

ZoomZ

I'm not sure they will move away from their Philosophy (P2M). They did the tests and have the engineers. Not sure if they have any long term results/affects.

You can opt for the soul function 3 piece like i have.

Can you still install the OEM stays along with the P2M unit?

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“Action without vision is a nightmare.”

Andrew's Z

Unfortunately the way this product is designed it will interfere with the mounting point of the stay without modifying the existing holes of the stay bracket. I may explore that option or....

I may just end up posting this one for sale and getting the 3 point kit from Soul or other vendor.

Thanks everyone!

Tractionless

I feel that's the wisest choice.

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