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1999 Infiniti G20t for NASA TT6 Time Trial

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Good evening everyone,

I have been doing some reading on your great site as well as many other resources on this car, but ultimately everyone's situation is a little unique so I am seeking your input.

The goal for me is a reliable car that I can drive to, participate in, and hopefully drive back from events. I do have another car that is my daily so if this ends in tears, I can still get to work.

My target class is the lowest time trial class, TT6. This is an 18:1 power to weight ratio class. The class calculator can be found here if anyone is interested.

From the sources I have looked at, this generation weighs about 2,9xx lbs and I'm estimating ~125 whp stock? With me in race gear, we're at about 3,1xx lbs and I'm guessing a power to weigh ratio of ~ 25.2, based on the 125 whp estimate.

I'm not interested in spending thousands on a DET swap and I'm not pulling the heater core to save 3lbs.

So with that in mind, my questions are:

1. With a gutted interior and a/c pulled what could the weight get down to? I'm estimating it may get down to 2,6xx
2. What can the stock engine handle without compromising reliability? Again not spending thousands. I'm talking about basic bolt-ons, streetable tune, etc. I was estimating ~135hp with basic bolt-ons

With the additional points you get for FWD, base trim aero, and not running full slicks, this would allow for 162-169 whp at 2800 lbs with driver.

Also, wanted to see if you guys could clarify from the calculator whether this would apply on the P11 chassis
- Suspension design utilizing upper “A-arm” or “wishbone” type control arms (front or rear) -0.7

By my estimates, the car cannot get light enough or develop enough power to compete in this class, but I wanted some validation or to see if I was incorrect in my estimates.

If you guys think 2600 lbs and 150 to 155 whp is reasonably achievable, then I think it could be a fun project
 

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Good evening everyone,

I have been doing some reading on your great site as well as many other resources on this car, but ultimately everyone's situation is a little unique so I am seeking your input.

The goal for me is a reliable car that I can drive to, participate in, and hopefully drive back from events. I do have another car that is my daily so if this ends in tears, I can still get to work.

My target class is the lowest time trial class, TT6. This is an 18:1 power to weight ratio class. The class calculator can be found here if anyone is interested.

From the sources I have looked at, this generation weighs about 2,9xx lbs and I'm estimating ~125 whp stock? With me in race gear, we're at about 3,1xx lbs and I'm guessing a power to weigh ratio of ~ 25.2, based on the 125 whp estimate.

I'm not interested in spending thousands on a DET swap and I'm not pulling the heater core to save 3lbs.

So with that in mind, my questions are:

1. With a gutted interior and a/c pulled what could the weight get down to? I'm estimating it may get down to 2,6xx
2. What can the stock engine handle without compromising reliability? Again not spending thousands. I'm talking about basic bolt-ons, streetable tune, etc. I was estimating ~135hp with basic bolt-ons

With the additional points you get for FWD, base trim aero, and not running full slicks, this would allow for 162-169 whp at 2800 lbs with driver.

Also, wanted to see if you guys could clarify from the calculator whether this would apply on the P11 chassis
- Suspension design utilizing upper “A-arm” or “wishbone” type control arms (front or rear) -0.7

By my estimates, the car cannot get light enough or develop enough power to compete in this class, but I wanted some validation or to see if I was incorrect in my estimates.

If you guys think 2600 lbs and 150 to 155 whp is reasonably achievable, then I think it could be a fun project
Hey there! I'm chief of tech for my local NASA AZ region. I don't have a p11 but I do have a 95 P10, and I can tell you without a cage you can get the car down to 2100 lbs with no cage, gutted, Lexan side and rear window. I also wire wheeled EVERTYTHING out of the car, cut out door skins, B pillars, the works. With cage and me its 2575 lbs. This is also with a VE, no AC equipment, etc.


19722


The P11 doesn't get the NASA A arm/wishbone points, since its a multilink, specifically OEM, you don't take points for that.

As far as longevity, I have an SR20VE, its been in the car since 2002, tracked relentlessly since then and it just did 180 HP with a new ECU and tune. They are VERY reliable and the DE is just as reliable, just keep fluids topped off, radiator working (I still use stock!) and you'll be fine.
 

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Discussion Starter #3
Thank you very much for the detailed reply. Great news that this might be an attainable goal. Potentially picking the car up Friday afternoon
 

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I think it is totally possible. I'd find a manual 5 spd with no sunroof, then put a VE swap in it and taking parts off until you got to where you wanted to be.

My old P10, gutted interior, primera bumpers, carbon fiber hood/trunk was 2270. And I still had all the metal in the doors, all the sound deadening on the floor, and didn't hack out the rear shelf.

And I drove it everyday on the street for 5+ years putting well over 100k miles on it so yeah it was a completely functional car just didn't have anything more than needed for driving.
 

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I've been running with NASA since 2006. We ran a P10 (95 G20) in PTF and TTF for 12 years with NASA but never prepped the car for TT6/ST6 because we sold it before the rule changes. My concern with a p11 is ability to be competitive in TT6. Its heavier than a p10 which already is a challenge to reach the 18:1. Keep in mind the rules dictate you must use a USDM engine and transmission for TT6/ST6 so you can't just run a VE and turbo anything is not legal for TT6. You will be going up against 2300 pound Miata's (which is what we have now for TT6/ST6) and is the favorite for the class. Honda Civic's and Acura Preludes are also rather competitive in TT6/ST6 (an Acura won NASA Nationals last year). Keep in mind the Honda/Acura is lighter and easier to reach the power to weight. Bottom line my biggest concern with a p11 is ability to loose enough weight yet still make it comfortable enough to be a daily driver. With our former 95 G20, we no longer had A/C but kept luxury items like the power windows, cruise control and heat. Our weight in that car was 2800lbs and it ultimately was more like 21:1 (not 18:1)
 

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Also keep in mind the hp is now an average calculation so you wanting to attain 155whp doesn't translate to 155 avg HP either. You can probably get to 155hp with BC2 cams (shameless plug is we have a brand new (or used) set for sale) as we had BC2 cams on a former 200sx SE-R and it gave us 147hp peak on a dynojet complaince dyno at the track on a junkyard 95 g20 engine and stock ECU with the only other mods being 2.5" ssac exhaust and a fidenzda lightweight flywheel.
 

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I've been racing my 2000 G20t since 2010, mostly Autocross but some open class trackdays too. I'll tell you from the get go, there are FAR better chassis out there, if you don't have a P11 already I would get something else. Heck even my B15 handled far better with less mods and that has a basic MacPherson strut front and similar beam setup rear.

The biggest issue with the P11's is the rear beams and overall poor suspension design for the chassis size and weight, leading to massive understeer. It takes a lot of modifications to get these cars to handle decently, by that point you rack up points (or SCCA classes, Hello SMF with one single mod).

Now I will say P11's do tend perform better on road courses over tight and technical autocross courses, so you might not need nearly as much many hacks as I did. Here's list of mods that I had to make to get my P11 to finally handle on par with fairly stock Legacy GT and less modified B15:

  1. Coilovers: 8k Front, 10k Rear. Need a lot of rear stiffness to keep the beam from moving and showing it's ugly geometry. I started with 5-6k Front springs, but I've been slowly increasing the rates, once again to keep it's ugly geometry from showing. Remember any suspension will work, if you don't let it. ;)
  2. Shorter UCA's (or camber adjustable bushings), -10mm Cusco UCA's only gave me -1* camber at my moderate ~-1" drop.
  3. Lower UCA Mod, this really helps the camber curve become more aggressive
  4. UCA Caster Mod along with Caster LCA bushings: These cars need a ton of caster to counteract the massive 16* SAI.
  5. Anti-Lift mod, helps with overall traction, especially in straight line.
  6. Panhard Bar to replace the high roll center, binding Scott-Russell Link (SRL). Stock roll center is 12-14" high, which overloads the front tires.
  7. Biggest/Stiffest Rear Swaybar - I'm running an Addco A32 maxima one on full stiffness
  8. Bending the Rear beam to 0* toe, stock is around 1/8-1/4" toe in, which cause massive understeer.
  9. Hard Poly bushings everywhere
  10. 17x9 wheels with 255 sized tires and a crap ton of fender pulling/rolling
  11. Increase chassis rigidness as much as you can, thus strut bars front and back. Nissan took a ~2600lbs Primera's, which I hear handle great, and added luxury components to it and sold with pretty much identical suspension. Alternatively you could put it on a diet.
  12. 6 Speed, for that sweet sweet helical LSD (over VLSD)
I still can't get enough camber on my front tires to avoid chewing them up, even with all of the mods I've done. The camber curve is just not aggressive enough with our convoluted Multi-Link suspension. That plus I think my sub-frame bushings are to blame, one day I'll get around to custom making some.

This doesn't even begin to cover power additions, I've personally have been VE+T/DE+T pretty much since day one, so power has never been a concern for me, but putting it down can be tricky.
 
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