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  1. #1
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    Top Speed for an HPF car?

    A question was posed the other day that was pretty interesting. Has anyone gone all out on their Stage 3 and up HPF car and attained 200MPH yet? On paper with tires about 25.7 inches in diameter and stock transmission and differential, an E46 M3 can just barely break 200MPH based on its gearing. Bump the redline to 8200 RPM and the theoretical top speed is about 206MPH.

    What is the closest anyone has gotten to the magic two ton mark? GPS or VBOX(GPS based) not speedometer reading.

    What kind of HP do you think is needed? And how much tarmac is necessary? Any thoughts?

    I was thinking 800HP and 2+ miles to reach 195 or 200MPH and .5 to .75 miles to brake safely. I am just guessing. Maybe somebody has a better idea based on some sort of data.

    I dont think anyone has done 200mph yet, have they? On paper it SHOULD be possible with out resorting to a new differential.

    Why do it? Because its there. It was not until fairly recently that the 10 second quarter mile was broken in to. Why not try the 200MPH club now that there are more than a few 800+ RWHP M3's out there?

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    I think there is more than enough power the issue is really the gearing/tires.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I think there is more than enough power the issue is really the gearing/tires.
    http://www.bokchoys.com/differential...calculator.htm

    Actually, if you click on the above link, it shows 225/45x17 for a tire size to get 193.16mph.
    If you put in 255/35x19 then you get 201.32mph!!


    Then add only 200 rpm for a 8200 rpm redline and you get 206.35 mph! It looks like the math on paper anyways supports a 200mph run on the stock diff.

    I dont think we have a gearing issue. 206mph is a perfect target. if the differential were changed, considerably more power would be needed.

    It appears that with the right tires and a reasonable 8200 rpm red line, that 206MPH can be achieved. If the number is VERY easily reached, a more ambitious 220 MPH could be obtained by YES, changing out the differential. That is a considerable expense that most may not be willing to go to.
    I am going to have a redline of 8500 so I will have a good buffer zone (I hope) to get my Two Ton Credentials. I will need all the extra power I can get to overcome the bad aerodynamics of a soft top convertible.

    I got a text that my stage 3 is supposed to run today for the first time. Supposed to. Anything could go wrong. But thats where we are right now.

    I would like to make a 200mph attempt about a month after the car is fully tuned..motor, chassis(suspension) and body (aero tuned)

    I have an open dump option running on E85 with heavily modified exhaust mani and intake tube. Huge 2150 FIC injectors and monster Aeromotive Eliminator pump. My rag top is my only real issue.

    I dont have a good choice for a low ET quarter mile car...too heavy. It has never been very good at the strip. HPDE is fantastic though. I might as well try the longer 1/2 mile, mile, and top speed events. Once it gets rolling it may be a decent performer.

    I want to know who else has tried an all out assault on a Stage 3 or more, top speed run.

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by Bdave Click here to enlarge
    http://www.bokchoys.com/differential...calculator.htm

    Actually, if you click on the above link, it shows 225/45x17 for a tire size to get 193.16mph.
    If you put in 255/35x19 then you get 201.32mph!!


    Then add only 200 rpm for a 8200 rpm redline and you get 206.35 mph! It looks like the math on paper anyways supports a 200mph run on the stock diff.

    I dont think we have a gearing issue. 206mph is a perfect target. if the differential were changed, considerably more power would be needed.

    It appears that with the right tires and a reasonable 8200 rpm red line, that 206MPH can be achieved. If the number is VERY easily reached, a more ambitious 220 MPH could be obtained by YES, changing out the differential. That is a considerable expense that most may not be willing to go to.
    I am going to have a redline of 8500 so I will have a good buffer zone (I hope) to get my Two Ton Credentials. I will need all the extra power I can get to overcome the bad aerodynamics of a soft top convertible.

    I got a text that my stage 3 is supposed to run today for the first time. Supposed to. Anything could go wrong. But thats where we are right now.

    I would like to make a 200mph attempt about a month after the car is fully tuned..motor, chassis(suspension) and body (aero tuned)

    I have an open dump option running on E85 with heavily modified exhaust mani and intake tube. Huge 2150 FIC injectors and monster Aeromotive Eliminator pump. My rag top is my only real issue.

    I dont have a good choice for a low ET quarter mile car...too heavy. It has never been very good at the strip. HPDE is fantastic though. I might as well try the longer 1/2 mile, mile, and top speed events. Once it gets rolling it may be a decent performer.

    I want to know who else has tried an all out assault on a Stage 3 or more, top speed run.
    I would imagine the differential change would be the cheapest upgrade (in relation to what you are doing to your car currently) - if you want 200+ (or 220+) speeds, that would be something I would seriously consider. With 800 horsepower - you really should have no problem at all reaching 200 - however, considering you have a convertible I would be more than concerned for you if you didn't have a rollcage. This car was not intended for 200+ speeds, and 220 is a HUGE leap above 200... If you are going to do it - do it right (safely) - and get your record. I think it would be awesome to have a 200+ E46 M3 vert. Click here to enlarge

    Some of the guys with the E9x series M3 have been over 206 miles an hour (333ish km/h) - http://www.bimmerboost.com/content.p...-hour-at-Nardo

    I would imagine that any car with 500 horsepower would be able to hit 200 with the proper gearing - the car above had a claimed kit 570hp, so to the wheels - I would think it's right around 500... With 800 to the wheels, again - no issue, just gearing, aero and rollcage are the thigns I would be looking at if I were you.

    Good luck - let us know how this goes, very interested in this.

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    Click here to enlarge Originally Posted by Bdave Click here to enlarge
    Actually, if you click on the above link, it shows 225/45x17 for a tire size to get 193.16mph.
    If you put in 255/35x19 then you get 201.32mph!!


    Then add only 200 rpm for a 8200 rpm redline and you get 206.35 mph! It looks like the math on paper anyways supports a 200mph run on the stock diff.

    I dont think we have a gearing issue. 206mph is a perfect target. if the differential were changed, considerably more power would be needed.
    Mathematically it works out on paper but it would be great to have more gear if top speed is the goal.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    I have no intention or plans to do a differential change. Either the car will make 200mph with the current gearing or it will not. Its that simple.

    I feel optimistic with an 8500 redline I will have enough gearing to make 200mph. If I dont, I wont cry over it. It will be an adventure just to try. I plan to look at it as an expedition with lots of carefull planning and preparation and a support team, not to mention documentation. I dont discount the danger involved and will only make an attempt when I have confidence in my car and myself.
    There are several professional experts in my area I intend to enlist to aid my in my quest.

    First off, I need a working car. Last news I got was a text at 6PM "Still working." It sounds like the car will not be running today. Hopefully tomorrow. My shop at least had the intention of making it happen today. So we must be so close.

    I will visit this thread from time to time to give updates on Dyno results and definitely some video. I have a couple HD vid cameras. One fantastic stabilized Panasonic model that is incredible. My roll bar will have 2 camera mounts.
    Last edited by Bdave; 08-02-2012 at 07:24 PM.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Mathematically it works out on paper but it would be great to have more gear if top speed is the goal.
    I dont want to push things. 201 MPH would be perfect.

  8. #8
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    Click here to enlarge Originally Posted by Bdave Click here to enlarge
    I dont want to push things. 201 MPH would be perfect.
    Well then, I wish you luck. We'll be here to support you in achieving your goal.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    Thank you. Succeed or fail, it will be most interesting to attempt, safely, at all times. I will provide full documentation of my efforts.

  10. #10
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    Click here to enlarge Originally Posted by Bdave Click here to enlarge
    I will provide full documentation of my efforts.
    Definitely looking forward to this, would be quite the milestone.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    Has anyone done a SMG III swap in E46's?

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    Click here to enlarge Originally Posted by Sorena Click here to enlarge
    Has anyone done a SMG III swap in E46's?
    Only with a V10 swap as well.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    Another thing to consider in trying to do a top speed run in a heavily modified car is the difference between street, track, and top speed runs. On a top speed run, the motor will most likely see long periods of sustained high boost. This is completely different than going WOT for a few seconds at a time, which is what most of the runs in these cars involve. Even when racing on the highway...

    Attempting this can bring on all kinds of new issues. I've seen a couple of guys have these kinds of problems at the Texas Mile for example.
    Click here to enlarge

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