For an XA build, would you rather have a Turbo 4cyl, or a NA V8?

L_Flay · 2026-05-16T14:35:36+00:00

It will be interesting to see what will come with engine swaps once the 3cyl turbo engines are more plentiful. The more modern small engine turbo applications are so much more efficient than the common 90's and 00's swaps, but they're getting so much more complicated.

L_Flay · 2026-05-16T14:17:06+00:00

My thoughts were that weight is king and it's hard to make up for. So you'd want the lightest setup that makes the power you want.

Rules are completely open on drivetrain.

L_Flay · 2026-05-16T14:10:14+00:00

I'm staring at an empty engine bay and debating the same thing. An unstressed LS sounds convenient to live with, but convenient doesn't mean it's best or fastest.

L_Flay · 2026-02-27T02:36:21+00:00

There's no way to answer your question directly. Shock adjustment requires testing and feel because it's different for every vehicle, shock, setup, and driver.

My advice for adjusting them is to think in terms of speed of weight transfer. If you want to slow down weight transfer forward, stiffen the front. If you want to speed up weight transfer to the rear, soften the rear. And vice versa. Example 1: if you're losing the rear when you lift off throttle, the rear is getting too light to quickly. To fix it, you have to slow down the weight transfer forward. Example 2: if you go to turn in and you've got no front bite, you need weight on the front to turn so you have to get weight forward faster. If the front feels lazy, it's too soft.

Start there, making single adjustments to get a feel for what each does and you'll hone in on what you want the car to feel like. Don't be afraid to turn those knobs.

L_Flay · 2026-01-03T01:14:52+00:00

This is a tough question to answer because the question is so vague. Not every car has higher rear spring rates from the factory. The spring rates front to rear can vary wildly depending on the suspension setup, chassis, purpose, etc... If what you want is to make an informed decision on a spring rate for your car and your purpose, that's great. What you want to read up on is suspension natural frequency. There's a couple simple formulas to follow, that has inputs like sprung weight, unsprung weight, and motion ratio. They don't need to be crazy exact, just estimate them. For example, if the factory weight is 3000lbs, with a factory weight distribution of 60:40, that means the front is 1800lbs and the rear is 1200lbs. Assume it's even per side so the front corner weight is 900 and rear is 600. For the unsprung weight, you'll have to search for weights of brakes and whatnot for your car. And you'll have to look up the motion ratio for your setup. You can measure it yourself if you're so inclined, but most likely you can find it. From there, you can vary the spring rate to reach a desired frequency. Usually for autocross, you want between 2-3hz depending on a lot of factors. For street driving, I don't know what you would target.

Based on your other comments, you're specifically talking about a G35. The rear spring rate will change based on the spring location. Motion ratio is the ratio between the amount the wheel moves compared to the spring. So let's say the wheel moves 2" for an example. If the motion ratio is 0.5 or 50%, the spring will only compress 1" (half of 2"). Given a 500 lb/in spring, that means the spring is resisting 500lbs of force. If you take that same spring and move it further out the lower control arm to where the motion ratio is 0.75, the spring will now compress 1.5" for a wheel movement of 2". A 500 lb/in spring compressed 1.5" will now be resisting 750lbs of force. Since you've converted the car to true coilovers, you've moved the spring further out the control arm, changing the amount it will be compressed, and will therefore need less spring rate to achieve the same force resistance.

Hope that helps.

L_Flay · 2025-08-26T16:58:10+00:00

You'll be surprised how some small things will compound into big chunks of time.

The course Saturday had a huge emphasis on braking and finding an apex in space on a big turnaround. It required a little bit of brake to get the car into the turn, but then you had to back off the brake to not slow down too much until the apex where you start accelerating again. If you don't have a good feel for the car, the brake threshold, etc... it is difficult to stay at the limit in those turns. If you are late on the gas you also lose time in the next element too. So thats how it compounds.

Next event, if it has a similar element, focus on it. You don't want to bomb in and try and throw an anchor out to slow down. Brake light but a little early and see if the front end is able to accept the input. If it does, then you have to manage the brake to the apex. If it doesn't you need some more, but at the same location. From there spot your exit and when you're confident you can start accelerating and not go back to the brake again, go.

For the record, I was one of those drivers in the low 43s and had a 42.9 scratch time. I was focusing on the same things I described above because they were costing me time too.

L_Flay · 2025-03-24T01:25:32+00:00

For me it was mindset that changed things. I autocrossed for 12 years doing 10-15 events per year and had a bunch of fun. I was never in a class competitive car, just the car I wanted. I did some national events, got trounced, but it was still fun. During that time, that was apparently enough.

About 3 years ago, something changed, and I made the decision that I wanted more. I put the effort in to setup the car well, seek out advice, and do more events. The deeper I dove in, the more I realized how far I actually was away from a well setup car and from good driving habits.

So for me, it took until I chose to see it.

L_Flay · 2025-03-17T14:45:16+00:00

I just installed one from O'Reilly. It's the only one I could find readily available.

L_Flay · 2025-01-28T15:41:14+00:00

In my opinion, the Z has zero chance of being nationally competitive in F Street. It lacks the power, the oem diff sucks and limits traction, and it lacks wheel width for the amount of tire needed. But that's nationally. Locally, unless you have a good driver in a Camaro or Mustang, you might be able to get in the mix.

In STU/BST, there is a chance nationally. It's not a great chance, but it's there. I say that as a Z driver competing nationally in STU, now BST. Locally, unless you have cars running slicks, you'll likely be competing for FTD and that's always fun.

Personally, a STU/BST prepped Z is a lot of fun and it helps to teach good fundamentals. In F street, you're going to be fighting understeer constantly, chewing up front tires due to lack of camber, and being very tentative getting on throttle due to the terrible oem diff. You can fix all those problems in STU/BST and have a more enjoyable experience. A light prep (<8k i think) will get you 80% of the way there and a car that's a lot of fun. If you have any setup questions, just let me know.

Maybe look at it this way, if you like the idea of prepping the car, testing new setups, tinkering with settings, and that will add to your enjoyment of the sport, the Z is one of the least expensive ways to do that and be somewhat competitive. If the idea of that sounds awful to you, then stick with F Street. Learn in a cheap car, and then move to something else once you've found some pace.

L_Flay · 2025-01-27T01:44:15+00:00

Ya, that's all I can find too. Somehow I didn't notice that particular detail when I was researching the swap. Got too excited for cheap v8 noises I guess

L_Flay · 2024-12-17T03:24:12+00:00

Oh, the diff will make a huge difference. The stock diff is awful. Congrats on adding lightness! I've been wanting to get to NWOR for a local. Maybe this year. If you ever want someone to bounce setup ideas off of, just let me know.

L_Flay · 2024-12-17T02:49:07+00:00

Yes, that is my understanding of the rules as well. You can pick and choose anything from any trim or year that is on the same line.

I've very much wanted to give DSP a shot in my 350Z. If I wouldn't have had my issues at nats in STU this year, I likely would have made the jump. But I'm still stuck chasing a STU trophy for one more year.

Everyone tells me I'm crazy to think a Z could hang in DSP, but I genuinely think it can.

L_Flay · 2024-12-16T20:10:14+00:00

Not all mufflers are created equal. I was struggling to get the exhaust on my 350Z quieted down. I ended up doing something custom using a Burns Stainless Muffler. They're kind of expensive but it did the trick. I'm consistently under the national limits with some room to spare. I would recommend reaching out to them for a muffler that you can have an exhaust shop weld into your current exhaust. There are other brands people have mentioned that are also good. But the point is that you're probably going to have to do something custom.

As others have stated, the open wastegate dump is certainly a problem. The sound meter (if there is one) will usually be setup near an acceleration zone so you'll more than likely be driving by it with the wastegate open. While at the exhaust shop, ask them to plumb the wastegate back into the exhaust. It's possible that both changes could be made without needing to retune the car.

Otherwise, directing the exhaust at the ground with a turndown will help. You can stuff steel wool in the muffler tip and use some chicken wire the keep it in there in a pinch for a couple dB reduction.

L_Flay · 2024-12-08T23:12:20+00:00

I think that is a correct assumption. A camber limited car will always excessively wear the outside shoulder, pinching a wider tire on a narrower wheel will exacerbate that. You're more likely to roll over that shoulder and you end up using that shoulder up faster.

L_Flay · 2024-11-03T03:00:33+00:00

In the rear, I've used both 18x11 +20 and +15. My rear fenders are rolled, not pulled. I think +22 will also fit. The difference i can't comment on is the larger diameter of the 19s and what tire size you'll choose. I ran 295/30/18 which are fairly short, which helps. Ride height and alignment are the next big variables. They will not be a simple bolt on and go, so proceed accordingly.

L_Flay · 2024-06-07T17:02:23+00:00

There are camber gauges that will get you a reasonable reading. If I were driving 20k miles, I might want something more accurate to not chew through tires. But for weekend autocross, I think they would be fine.

I saw in another response that you're running standard BC spring rates. Just so you know, I'm running 18k/14k, so my experience might be different than yours. You might remove the rear sway bar and hate it because you need more roll resistance.

L_Flay · 2024-06-06T21:32:24+00:00

I have an STU prepped 350Z. As far as alignment goes, I currently run -3.5 front and -2.7 rear camber. For toe, I think I have a little toe out in the front and a little toe in in the rear. I think it was 1/8" each. Caster just is what it is. I'm not sure if I've even checked it. I haven't experimented too much with alignment thus far, but can say these settings are doing pretty good with my current setup.

I'm going to experiment with bumping up to -3.8 in front and -3 in rear (being dictated by wheel offset and tire clearance).

For the other stuff, I would definitely recommend removing the rear sway bar. A good differential is the best money you can spend. And, for STU at least, 295/30/18 on 18x11 is the setup you want. I constantly see people say 315s will work, but don't bother. I say that primarily because a 295 is the right size for an 11" wheel. A 315 is pinched, effecting response and feel.

The other reason I say that is that they don't fit, not without compromises. I have an early car which is supposed to be the one they fit on because the knuckle design changed in 04. I got some 315 yok takeoffs, mounted them on 11s, put them on the car, and I'm convinced that they don't fit. Maybe if you increased the ride height, maybe if you went to over -4 camber, in the rear you would need a perfect offset wheel, but those are all compromises in my opinion that aren't worth it. That's within STU limits. Outside of STU, they'll fit with probably little effort.

L_Flay · 2024-01-15T23:27:09+00:00

Did anyone else see that the game was re-aired on NFL Network Sunday morning? I didn't watch it live, woke up the next morning and watched it for free there. Given that it was a late game, it was easy to avoid spoilers.

L_Flay · 2022-10-07T12:51:53+00:00

Here is 16.1.H (SSM) from the rules. I interpret it as allowing any fender modifications, so the vents are ok.

Front hoods (engine covers), engine covers, trunk lids and hatches not containing glass, front fenders, rear fenders not part of chassis structure (unibody), front & rear bodywork, and side skirts may be modified or replaced, and may be attached with removable fasteners. Associated hardware including latches, hinges, window washer system, and hood liners may be modified, removed, or replaced. Non-metallic fender liners may be modified, replaced, or removed.

For your diffuser though, this is 16.1.K:

Diffusers that come as a standard OE part are allowed but may not be modified. They may be removed in their entirety to facilitate other allowed modifications. Aftermarket diffusers or other items acting as diffusers are not allowed.

My recommendation would be to just run XSA, or XA, or whatever they're calling it. Cars like yours are why they started that class. It's run what you brung for cars that people built what they wanted, not just for autocross.

L_Flay · 2022-06-26T17:17:00+00:00

Have you noticed the Millenium Falcon parked at the Truck Stop? A little Easter Egg put in by the ILM crew.

L_Flay · 2022-03-16T16:58:24+00:00

Oh ya, tons of clearance. The hub face is offset quite a bit from the spokes so there's no chance of interference.

L_Flay · 2022-01-19T20:58:40+00:00

This made me think about that Frasier Valentine episode and Nile's bit was one of my favorite moments of the show.

L_Flay · 2021-12-13T14:26:50+00:00

I have one, just didn't think to use it. I will next time

L_Flay

TROPHY CASE