Mudge

A lawnmower is apperantly 90db http://www.howstuffworks.com/question124.htm

I have twice pipes and a stock exaust manifold on my 73 240Z, the car is definately going to be louder @ WOT (aka WFO) than 90db, but I have the chance to run Laguna next month if I can do something about it. Does anyone have a muffler idea, or should I just run another muffler in the center? If I get black flagged for sound 3x I will get booted from the track, and that would be a waste of big moola. No I do not want a disk type muffler, too many horror stories. Most other adjustable mufflers cost way too much. Since the twice pipes route RIGHT under my damn rear end, I wouldn't mind ripping the setup off the car anyway and making up my own exaust, so I may do that, if I can do it reasonably inexpensively since I'm jogging multiple project here, on a budget of course. I do have a 280ZXT car, but I dont imagine I could steal that setup as with the downpipe/turbo setup it wont be the same dimensions as a 240Z NA car I imagine. Otherwise, I bet the muffler is relatively quiet, it looks either stock or low-performance, bah. Ideas for getting down to 90db or a tad less for safety? I dont expect to see more than maybe 6k RPM tops, I dont want to nuke the engine, especially since I dont know its timingchain /oilpump life.

A longer spring, if the # of active coils is also increased, will make the spring softer. I have the Hayne also but dont know the # of active coils, even though I recently cut 1.5 coils on some stockers to put on the front. doh :stupid:

The struts on the 81ZX are huge, compared to a 240 strut. The ID is not the same (not so important), but the stud distance is way off. I wonder however if the top rubber mounts are interchangable, I'm thinking no, but maybe there is a way to make that a yes. Since the car is ALOT heavier (it is when you push it!), I bet the bolts are beefed up as well, which means, wont fit.

Look at the pass side of the block, look for something that says F54 or etc, should be a letter followed by 2 numbers. Same for the head, pass side in the center and you can find out what the head is from.

2.8L engine vs 2.4L engine is about 25 cubes, so thats a "good" thing. I dont know the SCCA rules though, and I know that they classify based on certain things, so you'd have to check the rulebook for more than stock cubes, or engine from same bodystyle car/generation use etc.

Longer runners tells me torque increase, I have the intake though and have no idea if its good for either or though.

True, cleaning up an intake runner is fine, but a rough surface to some degree is your friend. Get rid of casting flash but dont polish an intake runner, exaust yes, intake nope.

I dont believe it would do a darn thing for flow, but you would keep the valves cooler, in theory. Polished valves OR coated valves, will be used in a high heat app like turbo/blown cars.

Lets mention WHICH Kumhos, there are 280-300 treadwear Kumhos and there are 60 treadwear Kumhos. The Falkens you posted are 200. Alot of folks love the Victoracers, or a V700 which supposedly is the same compound as the Victo, but with a bit more street friendly tread. Either way they dont last forever but will beat full on Hoosiers for wear hands down. There are other less desireable race tires that likewise last very long, if on the street into the thousands of miles, Toyo Proxes R1 I think is what I'm thinking of. People hate them for stick but they last forever, some series' use them due to rules. I'm going to try a Kumho tire, I used to use Yoko AVS Intermediates (160 treadwear), but they are NLA :mad:

You can trail brake (LIGHTLY!) or let off the gas slowly, otherwise it will want to bring the rear around on you. 275 is quite a bit in a Z car, must be FAST!

Unfortunately I dont have a video setup in my own car (not even a cage yet, I just got the car a couple months ago ), but a smooth driver will make it all look easy and like hes not really pushing it. Be smooth, and ye shall find speed Speed shifting, and that kind of thing is for drag, stay relaxed. The videos are of a 1988 Porch 928, which is a V8! Sounds awesome, a very nice car, although they get heavy in the later 90s... There is an aftermarket for them building up engines (and more of course) up to 396 cubes, sounds very anti-Porch which is why the 928 is apperantly the German "Por-Vette" I may have video later because there is someone who does the stuff and puts it on DVD, but I dont know when that will be. I will say that for my own class I held my own except for a 2580 pound Cobra with 275/315 tires, and 460 HP, no contest, once I let him by he was GONE. The 240 is mostly stock, 195/60 R15" (300 treadwear tires), dual Webers that are still not tuned right, steel brake lines and Wilwood brake fluid with stock pads all around. Way too much braking bias in the rear, I couldn't stand on the brakes without sliding forward, I dont have the tire for it regardless. For those that thing stock Z brakes suck, you need to drive an American car that weighs another 1300 pounds! I also had poly on the stock front bar, I have NO rear bar, so either my car didn't get the option or else someone took it off.

This is an 88 Porch 928 that was there, honestly I had no idea they had V8s! The car sounds, badass. I was not in this run group so you wont see me getting lapped by him. Following a red C5 hatchback in Session 2 - Does a mild tankslapper in Turn 10 (13 MB): http://www.jeepvideos.com/mpeg/030125sp-redC5wiggle.mpg Following a black 930 in Session 2 - Nice save from a sideways moment in Turn 8. Scares me, but doesn't seem to affect the 930 (10 MB): http://www.jeepvideos.com/mpeg/030125sp-black930save.mpg Complete lap of Sears without traffic in Session 3(26 MB): http://www.jeepvideos.com/mpeg/030125sp-open.mpg Following the black NV 02 Z06 in Session 4 - I promised the driver I'd post video of our great run together, but my camera ran out of tape. Doh. This is all I caught (20 MB): http://www.jeepvideos.com/mpeg/030125sp-blackNV02Z06.mpg

I have heard of it done in a 510, but not easy at all and probably not worth the expense IMO. What would you really use it for, unless you ran some freaky 4.56 rear gears or something, I dont see the use without a V8 and some torque.

Wow, I'd consider an electric pump, since it doesn't rely on engine speed to run quickly.

I'm going to guess 74 is when emissions hit, because that is how the American cars were. There were smog provisions like PCV and stuff, but 74 is when performance started sliding, and also the I believe 5mph front bumper law (or was it 2.5mph).

I dont know the hose diameters used, and this is where HybridZ comes in handy, but there is a 4.3L mini van radiator, all aluminum, that I will probably use. HOWEVER, even 25 minute road course sessions, I didn't see heat a problem AT ALL, the temp hardly picked up any over normal driving, amazing. I use about 90% straight distilled water.

Heh, and name a single American car company using CNC internals? Is that the ocean I hear? Cast internals are still abound.

Yep, and this is yet another reason going overly wide is a waste, contact patch will be dissapointing versus a tire that actually "fits."

The yellow Cobra that did NOT belong in the group Once I let him by, he pretty much turned on the jets and said adios!

In terms of MARKET value this person is obviously hoping for way, way too much. I've seen VERY nice cars that dont sell very fast at 4k.

http://www.dleong.org/2003/tt/ncrc1/ncrc1.htm Only in one pic, there was another, nicer looking 240Z there but in probably the same group as the photographer. This is the primered demon that I picked up not long ago (2 months), I'm in pic #13. I'll post more pix/video as I can get a hold of em. One car that I could not keep up with was a yellow/white striped Cobra replicar, that guy was fast!

Since in default form they have enough fuel for 3.2L I dont know how they dont have enough headroom if jetted properly, to support the power, but then again I dont have a hot F54 either to know for sure. Looking at the jets available though, I dont see how they wont work, guess I may find out eventually.

I have these carbs, and they need to be rejetted on the idle side. I just RECENTLY figured out a 15 MPG issue with these carbs, as for now I'm happy with them however on my 73 and will probably continue to use them with my F54 NA buildup. There is a bit of a learning curve if your not a carb guy, since not alot of people seem to use them anymore, AND those that have didn't figure out the MPG issue and just got rid of them it seems. Default idle jets on mine were 50/50 although for the Ford 1.6L (1 carb) they are listed as 55/50, I'm currently 75/60 but will try 75/70 and see if that changes things. If you do the "upgrade" and get stuck, let me know and I can help figure out MPG issues, OR Pierce Manifolds was very helpfull, I spoke with a young guy Doug and he explained why my MPG was so poor. I thought I was pig rich and I was lean at idle, and overcompensating with my idle screw, which caused richness off idle, doh! I dont yet know MPG because I just got these jets on thursday, but I'm in the 20 something area, I have heard of 24-28 with these carbs on I believe a 2.8L setup.

They may "fit" but they dont belong on a 7" wheel, 195-225 is the widest I'd go. Use an 8" wheel for a 245. If you look at how Porch GT cars do things, as well as other road raced car setups, dont be supprised to find 275s on an 11" wheel. If you drive a pickup truck with 80 profile tires, then you can be a bit more abusive, but on a low profile tire dont go wider than recommended.