Noob looking for answers: S15 SR20det in to S13

[epousard]

I plan on participating in the SCCA silver state challenge this September, and as I will be averaging over 110-mph, I thought a sixth cog would be advantageous as well as a nice newer SR20. I have my 90 240 just about ready, except for the engine. I have the proper resources for the swap, a four-grand budget, a lift and some friends. My question is, is the S15 power-train swap much more complicated than a usual SR20 swap?

[!Zar!]

You SO didn't search hard at all. And the 6th gear wouldn't make your car that much faster. I would rather have a reliable 5speed than a jdm bling 6speed. Instead of wasting the money on a newer gen sr buy a s13 red top and put the money you have left over into making the motor more reliable or into other chassis mods; but then you don't need any being as how all your are worried about is a motor right now eh?

[epousard]

Do you think the RPM's at 110-mph would be essentially the same for the 6-speed as the 5-speed, the 6-speed having ratios for acceleration rather than high speed cruising?

[g6civcx]

Okay, I don't think many people know what you're trying to do. Silver State is an open road top-speed race.

Even though you have the car fully prepped, I don't think $4k is a realistic budget for an S15 swap because it is much more complicated than an older SR swap. My recommendation to you is get an S13 blacktop and start rebuilding the engine. It's the best motor of the bunch IMO.

Do you think the RPM's at 110-mph would be essentially the same for the 6-speed as the 5-speed, the 6-speed having ratios for acceleration rather than high speed cruising?

Nismo sells gearsets you can get for the 6-speed. It's hard to say what the difference in engine speed would be since we don't know what rear end and tyre size you're running.

[IES13]

Agree with everyone...buy either a S13 red or black top! Use the left over cash for upgrades like cams, valves, head & port, turbo upgrade..etc..An SR from an S15 will cost you at least 3K easy. The problem with the 6 speed off a S15 is that its a close ratio. Because its the also the same housing design as a 5 speed, the 6 speed gears at not as strong as older 5sp.

[epousard]

That is exactly what I wanted to know, thank you guys for being kind to a newcomer on the forum. The mods done to my car are KYB AGX's, TEIN springs, about 1.5" drop, on 17 circuit 10's with ziex 215 45's, cusco sway bars, 26mm Z32NA front and rear (got a good deal),
nismo T/C bushings, megan strut tower bars (they were cheap and available when I got my KYB's they seem to be fine), VLSD. I still have a stock engine and exhaust, 148,xxx, runs fairly well. I figure I should replace some more bushings before too long, are the enegry ones super stiff? I hope to see some 240's at the rally, if I can get a solid engine by then... I love my 240, I've owned miatas' for a long time and had some success on the track with them, but never liked the snap over-steer and my legs were too long. Have a great day gentlemen.

[andrewmp6]

if you use the s15 you have to swap the rear ends too the speed sencor is in the diff every one i know that had the 6 speed hated it and it broke stick with a s13 or s14 one

[Dutchmalmiss]

i think you should get some better tires if you're gonna be going that fast. aren't ziex just beefed up all-season tires?

[NI_YON_Zenki]

S15's are designed for Wangan Racing. .. .

[sideview_180sx]

If you are running silver state classic, have you even invested in safety equipment. Like a cage primarily. The cost of an s15 swap is way past 4 grand, since you would need to drop in the rear pumpkin since the VSS is on the pumpkin rather the tranny like on s14 and s13. BTW have you driven the car at a constant pace above 100. Make sure the car is stable at speed rather then having the car that can get up to speed quickly.