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any way to get top speed??


davidh

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ive heard the 70-78 z's are no good at top speeds like 130+mph!? is there any way other than the g-nose to get better aerodynamics on the car to get top speeds like 160+????

 

also ive heard that the handleing is also a bit scary? is it just the suspension that does that or is it just cause of the areodynamics?

 

any expertise is appretiated(cant spell)! :-D

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Its both areodyamics and the suspension. The suspension is the easy part. From what I understand there wasnt much windtunnel time spent on the early Z's. The problem they have is they create a lot of lift at higher speeds due to air getting trapped under the car.

 

*Lowering your car can help....

*Putting hood vents in can help get some of the "caught" air out from under the car....

*Using an "aerodynamic body kit" and a spoiler will also help create more downforce and help "clean up" the air going over the car...

 

 

Hope that helps a little! :D

 

Guy

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1980 280ZX- no aero kit/spoiler

 

When I had the L28E in there I hit about 125-130MPH(my speedo only went to 85mph :roll: ) but when I calculated out the RPMS I came up with the fact that I was somewhere in that ballpark.

 

With the LT1- lowered about 1.5" -- it will have an aero/body kit, possibly a spoiler and headlight covers

 

I have hit 115mph but I had to slow down because my rear window louver broke off the hinges and went flying into the air about 30 feet straight up! :oops: So I slowed down and picked up the louver and called it a day! The louver will not be put back on either once I paint it this spring. I have no doubt that I can hit 160mph but I dont know if I have the balls to do it! :oops:

 

 

Guy

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I ad a 77 280z with more money in it than I care to remember. I twin turbo charged a 280Z motor with aluminum rods, aluminum flywheel, special ground and machined engine parts, Body kit, Fully adjustable suspension, Frame strengthening, Hidden and blended cage. The car was set for racing and would definitely do over 160 mark on an oval. I will see if I can find the slips of the oval track time runs, so that when you see the slips your mouth will drop. I did that about 15 years ago or so in Texas. Would I do it again, No way in hell. Way to much money in the car over 30K not including the car that was very clean. Driving at that speed, everything about the road seems very small. I did do a lot of ground effects to the car including under the car to get it there. Unless you have money to burn and a lot of talent with metal forming to reduce lift and drag, I would not go there. But yes it can be done and you will be able to break the tires loose in all 5 gears. These days to repeat what I did would probably be 60K or more and I had a lot of friends helping me out and saving money. Sorry if this is a downer but if you have never reached 160 or around 180 mph, you have no idea what things are like. 120 miles per hour is fun and can be easy to reach and fun. The difference between 20 mph to 120 mph is almost the difference you would feel doing about 160 to 180, this is based upon my experiences.

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yes i have done 160mph before. my bro's integra gsr! all i remember is that ever thing went light (my bro was the one driving by the way), remember how thay did the effects in fast n furious, when they would hit the nos.....well its not like that! j/k it is in a way that every thing is going so fast around you, that it realy gets you concentrating more!!

 

do you have pics of the car?

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Mat73GNZ - excellent link on aerodynamics. Thanks.

 

To date I have only gone 3,000 rpm in 6th - that's 120 mph but car had plenty left and still seemed stable at that speed. I will be out at Texas Motor Speedway on May 14th for a track day and hope to get it to 140 mph. All depends on the track, the car, and me. The car has the Motorsport Auto Aero II kit complete with the small spoiler on the rear. It also has the European spec springs (stiffer but not lower). Hood is vented and vents are wide open - no rain tray under them. Click link in signature for more specs on the car.

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Shoot, I thought you guys had bigger ones than that! I had my L22 powered 510 to 125 mph quite often, a few times on I-5. Then I upgraded to my VG30 turbo 510 with 340HP and could do 135 mph, which is about all you can push a brick. It would run mid-high 12s on street rubber & pump gas, so it wasn't too bad. Although fast by 510 (or most import) standards, I sold the 510 (brick) and went to a V8 Z (bullet) in the quest for more speed & power! (Tim Allen impersonation right here!)

 

My buddy with a 400 SBC in his 240Z (which is lowered and has a front air dam) raced (& beat) a GSX-R from 80 to 150 mph on the freeway. (not that would I recommend it, but this guy is also a damn good driver, autocross class champ in that car)

 

I've had our stock bodied AAR 'Cuda (factory Trans-Am car) up to 160 mph at Daytona, but it does have a small spoiler on the front. It would go faster, but with a 4.11 diff and a 4 speed, it redlined at 7200 rpm, which is 160 mph. Now, our stock bodied '73 Dodge Challenger Petty kit car has hit 180 mph w/o a spoiler. Oh yeah, that was fun!!

 

I'm sure my Z will be good for 150 fairly easily. I'll just have to find a track with a long straight or go down to Texas to run with Phantom. :wink:

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my stock bodied, triple webered, 2 1/2" exhaust 260z hit 132 mph with the 4 speed tranny. that was good enough for me considering the car felt like the front wheels were just touching the ground. any improvement to the front air dam will make a dramatic difference to the high speed handling, or lack there of, over stock.

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My almost stock bodied (a deeper front airdam) 280zx, lowered approx. 3" has done a true (not tacho) 155mph.

It still had some more to give (maybe 158-160mph), when I spoted a police car and had to make a test of my braking capability... :oops:

 

This was with a single turbo setup producing around 270hp, and the car was very stable at this speed.

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This is the text from a post recently at ZC.C that shows some interesting "debunking" numbers:

 

Author: Z boy (---.rh.psu.edu)

Date: Mar 21, 6:35pm

 

results assuming frontal area of 22 square feet, .45 drag coefficient and standard airpressure of 14.7 psi

 

hp frontal cd speed

150 22 0.45 129.3558304 (stock Z body/engine configuration)

200 22 0.45 142.3745137

300 22 0.45 162.9781336 (see how adding HP helps)

400 22 0.45 179.3806468 (even more but not so much more?)

 

286 22 0.35 174.41845 (stock Z with headlight covers, GNose, Bellypan, Radiator blockoff)

 

286 22 0.38 169.7021086 (stock Z with headlight covers and G-Nose OR stock S130 coachwork factory stock...)

 

345 22 0.45 170.750488 (a comparison number)

 

pumped out on the lovely MS Excel.

 

numbers match up pretty well i think

 

-z boy-

 

The link is:

http://www.zcar.com/forums/read.php?f=4&i=145523&t=145092

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This is the text from a post recently at ZC.C that shows some interesting "debunking" numbers:

 

400 22 0.45 179.3806468 (even more but not so much more?)

 

Now, that's what I'm talking about.......but nearly 180mph would be nuts except at Bonneville. I'd be good with a good 160 mph, just have to wait for a time and place to try it. :shock:

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Well... my 300+ hp 240Z was still pulling well at 135 mph but my gearing limited me to 143mph and turn 9 at Willow Springs got in the way of any further progress. That was with a .87 overdrive 5th, a 4:38 rear gear, and 25.2" tall tires. With a 4:11 gear I can get 153 mph and swapping in a 3:90 would get me to 161 mph at a 7,400rpm redline but I don't think the car can pull a 3:90 in 5th.

 

FYI... with a 3:36 rear gear the chart says I can go 187mph!

 

FYI2... My 240Z, in its earlier BSP configuration (front air dam, no rear spoiler) and an honest 200hp engine couldn't go faster then 135 mph with the stock 4 speed, a 3:54 rear, and 23" tall tires.

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My stock 280z two seater with the L28E/N47, 4-speed, 3.54 R200, about 300lb. worth of stuff (I live on a ship, so my home is my car) my buddy Steve, and myself..(total weight at least 3400lb!) topped out at an indicated 125mph@5,500 rpm on I-5 North. I was going on leave for the first time in over a year and was on my way back home to PA and my mom N pop for the first time in TWO, so I was in a bit of a hurry!

I guess due to the additional weight the aerodynamic lift wasn't a problem, the car felt rock solid. I guess the speedo is pretty accurate, huh?

I've since installed a MSA 3 to 2 header, 3" exhaust, and an air intake system with K&N, and a 280zx 5-speed (close ratio). I don't think it'll go any faster, need way more HP.

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disclaimer: I have heard that the speedo is inacurate after 125 mph. So the only real way to know is find another way to test the speed./disclaimer

 

According to my litta' Speedo, my car here, was doing, 144 mph.

 

I have a L28ET under the hood of my 71 with an early 5spd. I don't know the gearing in my R-200. Another factor in there. The Front end lifts way up. The car feels real light and touchy. I wasn't topped out but I am a too ball-less to go any faster. I've only gone that fast once. I normally keep it under 130 when I'm racing. To scary for an amature driver like me. I am now focused on how fast I can get up there instead of how fast can it go.

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