May Prelim question/comment.. Nissan SR20DET in STU

Have been contemplating this request for a long time, as Greg and Peter can attest, then I chicken out on doing anything to this car and spend the money on my Prod car.

I'm glad to see this one on the Prelim notes, however I'm curious why there's a -2mm restrictor limitation on there? Is this in addition to the -2mm that's already there for the RWD cars? (Any chance for a +1mm or 2.5% weight given back for a RWD car with McStrut? ;) )

Why choke the SR20DET any more than other turbos? Is this just a "cautionary" thing that is subject to update once the powertrain is seen in action, or has there been a proven case that this would create an overdog vs. something like the Solstices that pull away from everything in sight?

'Cause JDM. CRB is tacking adders onto anything non-USDM now; turbos get -2mm and everything else gets +2% weight.

If someone got serious and built one and demonstrated it was not an overdog then I'm confident the CRB would entertain appropriate adjustments.

crusty old farts. Just cause it's not "from here" means it gets a penalty? :dead_horse:
Might as well go drive my Chevy to the levee.. But I can't.. it's broken and I'm waiting on parts from Mexico. :shrug:

;) Crusty old farts is us, brother... Build it, or get someone else to build it. We got it in, we can make it right.

You and your funny Furr'in cars. Meanwhile I drive and race cars built in South Carolina.

yea grumpy old guys, after all JDM engines are propelling race cars us motors are not willing to do. :)

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Originally Posted by Greg Amy

;) Crusty old farts is us, brother... Build it, or get someone else to build it. We got it in, we can make it right.

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I'm trying to see how many people I can piss off first.. ;)

Does anyone know which SR20DET motor they are trying to get approved for STU.

Pick your poison; you can run the Blacktop if you want. Just recognize that the TIR is going to pair down the output possibilities while you're generating a lot of heat.

Focus on maximizing torque.

My vote would be S14 blacktop or S15.. You get a better head with the S15 engine, but you also pay a lot more. Both of them have a ball bearing T28 which will help spool and get the torque moving quicker. Plus the T25 on the red top runs out of air pretty quick. Since we're limited to stock turbos, the T25 just can't make the power needed to be competitive whether it has a restrictor or not. Well, at least not at weights attainable by the S14 chassis. (I don't see being able to get the car under ~2600lbs w/ my fat arse.)

When there's local boys putting down ~400/420 in a 2900lb Pontiac, it's going to be incredibly hard to make the SR20 competitive at 2700lbs with a 31mm restrictor that will give you roughly a max of ~300hp.

Solstice with the LNF has to run 2820# and a 34mm restrictor, and it has to remove -2mm for RWD. That's a 32mm hole; there's no way they're putting out even close to those numbers for STU.

If you can get the S14/S15 chassis down to 2675#, then you're running a 31mm hole. 1mm down but also 135# down.

The old SR20DET would be hard-pressed to compete with the technology of the Ecotec LNF, but in general this isn't a terrible pairing. And, if someone builds one and demonstrates it, it has the opportunity to drop that -2mm.

Build it.

If you were starting from scratch in building one, which chassis would you use. I am thinking of building one versus converting my ITA 240sx. I am looking at trying to find a Nissan for a national class for the runoffs at Daytona next year.

I wouldn't start from scratch- I would buy my S14 that's for sale and drop an SR in it. replace the 8 yr old coilovers, and you'll be well on your way to a competitive car. (I bought an EP RX7 that is/was quite a bit faster for the price it would take me to put an engine and suspension into the 240SX, and EP is quite strong here with national-level competition at every single race. STU is lacking in tough competition, so it doesn't make a ton of sense to me to spend a bucket of money to make it faster with little competition to run against.)

The S14 chassis is a touch bigger and heavier, but it's also a stiffer chassis and has better geometry in the rear subframe so you can get better corner exits. With the 5-lug hubs, you also get better wheel bearings that last a lot longer than the S13.

I will keep your car in mind when doing my research. Distance from Orlando will be an issue

Initial feedback from friends is the s13 hatch may be the chassis to use.

Your friends don't have a clue then- the hatch was the softest chassis due to the lack of tie-in around the rear struts. It's a big box, like a small minivan. the sloped rear roof is a touch better for aero, but not enough to make it worth the penalties in chassis stiffness. You can always counteract some of that with the cage, but you have to add more weight in the cage to make up for it, which makes the lighter S13 chassis less beneficial.

For STU, you also have to put a fuel cell in an S13. The S14 tank is in front of the rear axles, saddlebagged over the subframe (under the rear seat area). it's in a much better location for weight distro, and you have the better suspension geometry. You can also run the stock tank just about dry without starving for fuel. I've run a couple races where my fuel sample port was spitting bubbles after the race, but never had a problem on track.

Houston to Orlando is 975 miles, so it would be a good 2-day tow. Come up before a race weekend and you can run with the TX boys before you go home. Be sure to bring a big arse trailer cause I got lots of spares with it. :)

and the hatch is harder to make in plastic, not impossible by any means, but popping a plastic window into a notch is easier. the spec wing works well on the notch, too. not for nothing but I'd be all over the S14 JUST because of the strength and commonality of the hubs / wheel / brake offerings. and as for transport, there's always a transport service (not very expensive) or a trailer with an open spot shuffling things back and forth across our great nation. hell I bet you could have gotten ISC to swing over to Houston after the NOLA majors (I assume they went to the NOLA majors).

My friend works at Nissan Motorsports.

I appreciate all the feedback. Keep it coming. Just looking at all options.

I have many friends that work for NASA, but that doesn't mean they know how to build a space shuttle. ;)

If you're truly interested in the car, let me know and I'll work up a current spares list. I'm selling off stuff to make room in the garage, but still have like 3 transmissions, 3.9 4.1 & 4.3 diffs, 6 or 7 sets of 17" wheels, 3 diffs, spare doors, lights, gas tank, subframes, etc.

Matt, in my research the S14 and S15 have the same part numbers for the head assembly. I believe the power difference was entirely due to higher boost pressure and ECU tuning, which are open items anyways.

I'm very happy to see this even though it is a day (year) late and I'm many dollars short... I still have a bit of sweet spot for Nissan even though it is Honda and Ford for me this year.

And on less selfish note, I believe that this is a good move for the club.

How can it be a year late? It was approved a month after it was requested.

Oh, you want the club to pre-emptively know exactly what everyone wants to race and pre-approve it in advance? What are you, my wife...?

;)

You should pre-emptively remove that -2mm restrictor and then choke it if it becomes an overdog. The cat's already out of the bag with the USDM turbo engines and the NA guys are scrambling to keep up. Put the JDM turbo engines in the same boat so we're all on the same playing field.

For that matter, I'd also like to see some of the RWD/AWD penalty removed too since it sucks to watch an FWD car pull you out of the corner and get just far enough in front of you that you can't attempt to outbrake them. If the RWD cars are supposed to handle better, then they need a chance to be able to do it. It's like the whole DOT/slicks gripe when those classes are paired together on track, except now it's within the same class. pretty damn frustrating to get beat by a poor handling or poorly driven car simply because they have more motor.

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Originally Posted by Matt93SE

crusty old farts. Just cause it's not "from here" means it gets a penalty? :dead_horse:
Might as well go drive my Chevy to the levee.. But I can't.. it's broken and I'm waiting on parts from Mexico. :shrug:

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LOL - ST is pretty much the only place you can race a non-USDM engine/chassis in the SCCA, and this just changed a year ago. Crusty? Hell no, we're ahead of the curve!

please correct me if I'm wrong, but hasn't the SR16VE been allowed in GT for a number of years?

the crusty-comment I believe come from the "gah!!! furrin enjun!! throw lead at it!!!" part, which outside of very specific equipment is unjustified and the result of fear. I think everyone is relieved to see the gates opening, and the penalty weight for the ITR and 20V 4AGE kinda seemed to make sense a little, given the ITR's previous restriction and the uniqueness of the 20V (and it's longblock components) but it's pretty bittersweet when such a penalty gets slapped on USDM equivalent engines like the B16 just because it's JDM.

In addition to that, the lead is being thrown at 20 yr old technology. Nissan quit making the SR in '02, which the latest version went into production in that trim '99, which means it was designed in the mid 90s... But hey, that's still new for these guys! :D

In the end, physics is still physics. You can only suck so many CFM of air through a restrictor of a certain size, doesn't matter if it's 'Murican, Japanese, German, or Italian in origin..