NASA PT5/TT5 Class for 2018
 

Who here is going to run TT5 for next year? Granted new rules are coming out Nov 29th. Thoughts/tweaks etc?

I think with the 6 point dyno average, the S2K will really benefit from it.

My car already has front and rear aero, intend to install front Canards and depending on how much mod penalty I get, run as much of a stickier tire I can.

Car currently running TTD and fairly competitive.

Cheers,

Lutfy

Is there a non-official ruleset out yet? Car is currently setup for TT4 but is very underpowered/overweight for that class and is much better suited for TT5.

Official rules come out Nov 29, next Wednesday. Not much point in speculating til then.

I'm in a similar situation, currently set up for ST4. Waiting to see if I would have to really de-modify the car to fit into ST5. If I would, I might just stay in ST4 and add a supercharger. I'm hoping that I can just go back to running 93 octane instead of E85 and fit into ST5, but we'll find out next week.

Josh would love to have you in TT5. Glad there is interest with folks as in Mid Atlantic there were hardly any Twins. Rules will dictate but rumor has itthat we will have six point average for dyno just like TT4. If that's the case we are okay as our power band is low in the bottom end and falls off after 7k and that 7,5k reading works to our advantage.

Time will tell!

Lutfy

In for new info on TT5, my car has been in TTC due to "worthless" mods and having to take points for a OEM spoiler as aero.

Rules have been posted: https://nasaproracing.com/rules/supe...ng_5_rules.pdf

The mod factors for suspension and aero kind of knock me out of TT5 as my adjusted power to weight would end up at 16.00 lbs/avg whp (vs the standard 14.00 for the class).

That said, the class should be a good fit for those who haven't invested in aftermarket aero or heavy duty suspension mods (remote reservoirs, control arms, etc).

Do we need to take the -0.7 for upper A arm in the rear? If so, I am at -2.0 for mod factors and -1.3 without it. Same boat you are in, ja1217. I do not have aero but took the following:
Mod factors

Weight under 2850 -0.1
BBK -0.2
Rear Camber arms -0.5
spherical bushings -0.2
suspension -0.7
BTM aero +0.4
Total -1.3

A ARM? -0.7

I do not really see the car being competitive in TT4 either without much more power. Based on those rules I am at ~14.3 right now with 196WHP. Plus I would have the priviledge of always losing to Dave Schotz here in AZ :).

I think you are right about needing to take the A Arm/wishbone suspension points. The rules say if your car has wishbone design in either front or rear you need to take those points, and the 86 has macpherson struts up front, but wishbone in the rear.

That means my point total would take me to 16.7, definitely not going to make that. Here's how my adjusted power to weight looks like:

<2850 lbs -0.1
BBK -0.2
Rear lower control arm -0.5
shock shaft diameter > 40mm -0.7
Splitter -0.5
A arm/wishbone -0.7

Total = -2.7, meaning I would have to be at 16.7 lbs/avg whp

I think I'll stick with my plan of staying in TT4/ST4 and adding a supercharger.

Folks remember dyno is average not peak FYI. The top end dip and not being a linear curve helps some.

I am at 2870 with half tank of gas and intend to be there

Splitter .5
Independent suspension .7

I have oem brakes and MCS Doubles so no points there. Rear wing appears free?
Says camber arms take -.2 but I have camber plates so like before no points there?

In that case I come in at 15.2. Average whp to be at 187.5 meaning I will have to run e85! this is my track only but still driven to and from and will need a tire trailer to load the fuel jugs.

Looks like tires are free so must run R7 likely 225 to stay ahead.

Lutfy

I've done the math, my car averages right around 180whp on 93 octane, and 195 on E85. I'd have to add nearly 300lbs of ballast to my car as it has dropped a lot of weight, last I checked I think my comp weight is under 2750lbs.

On the tire side of things, there aren't any points, but they did change things to be a measured section width, so really you can't run Hoosiers bigger than 225, but you would be able to run like a 255 Maxxis as they would have around the same measured section width. I'd be interested to see how comparable a 255 Maxxis or equivalent would be to a 225 Hoosier. My own data has a 225 Maxxis being 2-3 seconds slower than a 225 R7 (same track, same day), but the extra width of a 255 for the Maxxis would probably help claw back some of that difference, but I bet the Hoosier would still be at least a second faster.

With the average power calculation, I am at 184.03. With a comp weight of 2750 and the mod factors, I am at 12.95 adjusted weight/power. If I add 200lbs, I am at 14.03, maybe I will give it a shot, not sure how long my mid 2012 engine would live under boost at this stage to aim for TT4.

I 'think' we do not have to take that 0.7 independent suspension hit. I 'think' until Greg clears this. Otherwise every single modern car short of an older Mustang will take this hit (its silly). From what I am gathering (take with a grain of salt), this is geared towards Mazda's and Honda's. They dont need fancy control arms etc. to get the required camber like we do.

I spoke at length with Edgar this AM and he is in the exact same boat.

My thoughts:

1) I have done testing with and without front aero and to be honest, really couldnt tell the difference in feel and with time. Possibly its beneficial but its not that it affected the balance and or laptime. Its also because my rear end is PINNED solid and I have a pushy car. Edgar, without a front splitter and rear diffuser with a not so agressive rear wing as ours, ran 1:22 at Summit just recently. Saves you 0.5

2) The rear control arm is crazy (IMO). Perhaps going with stock? I am at 2.4 neg camber with 13.25 inch gap from fender to wheel at the back. The other side is -2.5 or something (not even) but its not like I have noticed a disadvantage.

3) I know you wouldnt want to hear this (sorry) but that single adjustable shock can go? I have MCS Doubles (non remote) and I do not take any points. Very happy with the service and support as well. The delta between selling say yours (after contingency money to refresh) and getting a comparable MCS single if you'd like is hmmmm price of a set of tires. I know its not ideal but just saying.

4) DO NOT assume ever that the 255 tire will be faster. It will not be. I have tried 255 R888R and also 255 R1 BFG alongside 225/40 Hoosiers. Granted I am on stock diff but the gearing was messed up badly. Too damn tall. I thought I was smoking something so I slapped the R1s on Edgars car. Guess what, he ran slower than the 225 R7s. Emperical evidence. If you want, you are welcome to collect the 255 R1s (am in Rockville) and give it a shot. A six pack of Coronas for exchange :) Long and short, dont focus on that variable as I have skull Fed myself plenty there. At VIR the 255 R1s with less heat cycle were 3 seconds slower than the R7 255 (Hoosier 21lbs and 23 for R1s). I doubt the Maxxis would be any faster than 255 R1s.

5) @steve99 on this forum can send you custom maps optimized for your car. I have OFT btw. He can turn down timing up top so you make 5bhp less if it comes down to that.

I genuinely believe that if done right, you can be in TT5. And why not? I got my FRS because I was impressed with yours and Edgar's car so be fun to have more twins.

Worst case you take .1 for under 2850, .2 for BBK and say .7 for independent suspension. 15:1. Conservative tune you get to 175whp. 2625 min weight. Bingo. Splitter? 2712 min weight. Doable.

Boosting IMO becomes false economics. Reliability, heat, strain on tranny, axles...

Cheers,

Lutfy

Do you know diameter on those? Trying to get more info. I would be coming from CSG spec Tein SRC double adjustable/remote reservoir shocks. I was looking at the MCS back in the day, but ended up leaning towards CSG SRC or JRZ, both of which are -.7.

Looked at my invoice, it just says 2 Way Non Remote SHORT version (likely for the shaft). Shaft is very close to stock strut, no mention of diameter. Sorry.

I know for a fact that they do not take points. Confirmed by Vorshlag, MCS and informed Greg of the same.

I'd call MCS and speak with Wyatt.

Lutfy