well, its a long front stretch. considering they run the 1/4mile on it, with run-off room ect, and still don't get to the end of the stright-away.



note: when i did that, we were bypassing the chicane.

He did do a good job, but it's wrong.

He is dead on I am sorry. Every gage on our cars is off to some degree. Any mechanical system will be off to some degree unless it uses precise parts with some sort of feedback system. Speedo gears are only a close apporximation to average speed at some given point. You cannot add a half a tooth so they get gears that are close. For the same reason why you cannot get speedo gears for a 3.73 gear but you can for a 3.70 gear. It is in how the gear are made. How would you explain this? Maybe we are missing your point.

how so?

i can explain it to you mathmaticly if you want. proving its a ratio.

whats your thought on how it works then? and if its always off by a number.. like say, 3mph, why dont you just twist the needle slightly and it'll always be accurate?

Bone *** stock, not even an open element? Was the only tuning removal of the speed limiter?

very little tuning, open element, and speed limiter delete. that is all.

i know MANY stock peanut cammed 305 IROCs (not much more HP than us) that are easily hitting 140 or so on a straight like that.

Man you guys must put something in your octane. Ive been in three bone stock LO3s over 100 mph on highway runs and they were all dead. Starting from 65 it took a lot longer than half a mile to even get to 112, yet alone 130.. gooh.

How much you guys sell that gas for?

I agree. I would sit with the gas pegged in fourth at around 100 and it would seem as if the car was sitting still. The RPM's were stuck at 4500 or so. Even shifting into 5th and the car would pretty much stand still.

i think it all depends on the gearing and tune you gan not look at it as a lo3 cant go that fast throw some 2.56 or some thing in it and i bet it may take forever but it will fly but it will take an hour to get there

Even if you make some prodigy TBI, wont it still have a hard time going incredably fast because it only has 2 barrels for the air to go through?

Number of bores doesn't matter. An LS1 has a single bore. It is CFM that counts.

Drag Coefficient:0.38
Frontal Area:22
MPH Force (lbs) HP Required
10 2.1 0.1
20 8.4 0.4
30 18.9 1.5
40 33.5 3.6
50 52.4 7
60 75.5 12.1
70 102.7 19.2
80 134.1 28.6
90 169.8 40.7
100 209.6 55.9
110 253.6 74.4
120 301.8 96.6
130 354.2 122.8
140 410.8 153.4
150 471.6 188.6
160 536.6 228.9
170 605.7 274.6
180 679.1 326
190 756.7 383.4
200 838.4 447.2
210 924.3 517.6
220 1014.5 595.2
230 1108.8 680.1
240 1207.3 772.7
250 1310 873.3
260 1416.9 982.4
270 1528 1100.2
280 1643.3 1227
290 1762.7 1363.2
300 1886.4 1509.1

Well once i messed with my comp a bit ive got my 305 tbi's speedo needle to hit the trip reset button, dont know how fast but it was damn cool.

Stupid 3-4 shifting, thougth the engien was gonna explode till i got it up there and let it cruise at half throttle so it would stay in fourth

Interesting, minus the fact that you've done more to your car then me we have the EXACT same car. I can slam into my govenor like I'm driving down a mountain. I KNOW I could do at VERY LEAST 10-15 more mph... BTW I can hit it in 4th without red-lineing, but 5th makes it there almost as easily.

And on the speed to MPH off ratio, thats absolutly correct. Thats one of many reasons if I do have someone pace me (I've had to do it in more than one of my vehicles) I'll always ask someone with a newer vehicle. These half mechanical/half electrical speedo's are about as predictable as a scratchers ticket


Bruce (90RS305)

my L03 dynoed 152 at the rear wheels. granted, mines a vert so i'll have more drag, but she can speed past 114 without a problem.

if you cant hit the speed limiter due to power, somthing is wrong with your motor.

have to remembe that this is just what it take to over come the wind then you still have rolling force drive train loss and friction of the parts and stuff but it is a good idea

Can someone tell me exactly what that long list of number mean?

The point of that was to show how much HP it would take to go a certian MPH based on the 3rd gen specs of drag and frontal area. The data is flawed though and does not take into consideration drivetrain losses and rolling resistance as well as many other parameters to consider. There is far more to it than a chart.

if you are going off the numbers we get from a chassis dyno, then it is, the dyno numbers will figue in pretty much all of the losses (execpt for the friction from the front tires, the roting loss,and bearing friction). the HP number listed is the power needed to overcome the aero drag at those speeds, if you take your RWHP number, and plug it in there, it should be pretty close. assuming you can reach that number in you 1:1 gear. if you have to shift to OD, then the final gear ratio could become a concern.

Yea I know dynos will correct, but his data is theoretical on a striaght road with no head wind I believe.

EDIT: In the end it is a matter of opinion whether you think your car is pulling at 100 mph or not. I can hit the limiter with enough road in 4th gear without much of a hitch. However it takes longer than I would like and really does't feel like it is pulling as much as you guys describe. I geuss I am used to the pull of an LT1 or LS1 at those speeds and you just get used to what that feeling of pulling at 100 mph should be like. It is hard for me to claim that my car pulls at 100 when my moms base 3.8 impalla and my daily driver pulls harder at that speed than my LO3 ever did when it was stock. Stock LO3's can hit past 120 without the limiter but that was never really the argument once the limiter situation was explained.

i need to go back to texas... then i can test this impala Vs delimited L03 from a 100mph roll idea.... :lala:

come to wisconsin and we can test from 120 mph roll !!

not alot of LONG straight roads in my neck of the woods....



but we have a great view

very nice.

Stock LO3. We all now how these cars wake up with mods. Non the less it is sad. When I was bone stock I got beat by a half car length from a 50 to 100 pull against a new V6 malibu. It was embarassing.

heheh shifty, i know what you mean about the stock LO3 sucking from a roll.


If you want power from a roll you oughta build my combo, its insane from 50+ I havent been beaten on the street yet. Course i havent raced any C5s

but i sure love smoking those imports from what they think is their strength. From 65 I owned my buddies 300ZX TT repeatedly.. like rediculous car lengths and those are supposed to be fast from a roll

Oh yea I love heads and cammed LO3's. I am only sporting the LT1 cam now but my good buddy has his vortec 305 TBI and it hauls up top. I mean it pulls hard for a 305. He is shooting for mid 13's as well.

I've always wanted to drive Portland...but it's at the opposite corner of the States from Ga.

Just out of curiosity what was your exit speed out of turn nine on to the front straight?

I don't know about others with similar mod's but mine really starts pulling at 105 to 110

Top speed? Two hood pins and somewhere with less traffic would help there. The speed is cool to run at but that hood starting to push upward is what scares me! LOL

Probably alot slower than it should have been, something about the big wall getting very close to your drivers door its a tough one to call me speed on, the actualy exit from 9 is alot slower than when you actualy get up on the wall, and go WOT (well the really good drivers are WOT all the way out of turn 9) but with the chicane open, you have almost a half mile before turn 1, which is still a pretty high speed turn.

Thats ok, I think the curves are way better anyways!

So the stock hood can actually fly up at 100 or so? thats not good

Walls build confidence or fear. LOL

But you can quickly tell if you are loose coming off the corner or not.

One half mile sounds pretty cool to check top end especially if you come off the previous corner well. Always loved the layout of that track.

They can lift some. Mine has extra gap between the front bottom of the hood and the top of the nose that needs to be adjusted out. This lets more than normal air underneath. The jackass that repaired the car before I purchased it was not apparently in the correct trade for his level of knowledge.

I will fix it when replacing/repairing for paint.

Oh yeah....I've had the car to over 130 and still pulling

I have had my needle touch the trip odometer reset button. I was racing someone in a Honda. I was ahead of him until i hit 5th gear. These motors dont pull for anything after about 90. It is really sad, the dude went flyin by me like i was standing still. However, the car does feel good at speeds over 100. No float or anything.

153.7113316274522 @ 4600 in overdrive w/ 700r4 and stock size tire but z rated. I have open air element, pullies, 80 series flowmaster, gutted cat, and a stage one chip from tbichips.com. I also have sportlines, tokico 5 way, spohn sub frames, lower control arm and panhard with sphrical rod ends, edelbrock torque arm and poly bushings, kenny brown lower chassis brace... the only thing that was keeping me from going any faster was the tranny i couldnt give it any more throttle or it would kick out of overdrive and put me @6500 Oh i also have a nine bolt with 3.27 and thats it and about a 3 mile strech.

This was your L98 right. If so you missed the point of the thread.

i think he has a 305 but it is a tpi motor

yeah, the 'good' drivers slide their car to within a couple of inchs of the wall there. i'll get there, i wish i had more money to get out there more often. but between gas, brake pads, tires, and the cost to run, it makes for an expensive weekend.

yeah, its good to see a couple of series coming back, ALMS is back this year, but with CART in the status they are, that race might be done for.

no offense or anything but this is for u guys that say u cant pass 110mph. every 3rdgen car that ive drivin was able to pass that. i'm not sayin your lieing about the speed limiter but i dont think it kicks in at 110. do u guys have clogged cats or somethin bc i was doin 120ish( speedometer only goes to 120) in 5th gear and it still kept goin. my rpms were only at 2500 at 120. stock gears and everything. and for that guy that said he shifts 4th into 5th and it feels the same. what are u shiftin at? theres definatly a difference.

since this is still at the top, i wanted to add somthign.


my 305 is currently on its last leggs, i dont mind since the new motor is almost ready do be swapped in, however, its running bad.
dog slow.. slower then l03 slow.

for the heck of it, i maxed it out as far as i could lastnight.. uphill on one of the larger bridges going over the rivers.

it stayed at 110 going uphill... on 7 cyl.


if you cant hit the limiter with your l03, then you have a serious problem.

There is a lot of confusion going on in here.

The point was never whether or not some of us can hit the limiter. We for the most part agreed that we can without much problem with the right amount of road. However we do say it takes some time to get there. Now my deffinition of time maybe different than yours so there cannot be any real validty to anyones opinions. Because this is of an opinion I do not think an LO3 pulls at 100mph. Does it go faster, yes. Can it go faster, yes. But only if the limiter is removed. If you have enough road you can ever so slowly reach up to around 125 to 130 but it by no means pulls at that speed (once again assuming the limiter is deleted or dissabled). Just ride in a bone stock LT1 and LS1 and then tell me your stock LO3 pulls to and past 100mph. You will laugh and be embarrased. Many of you own and or ride in much faster cars and can attest to this. The fact is that the speed limiter is set between 112 and 115 depending on tire inflation (assuming we all run the same size stock tires). You cannot go by the speedometer because you are taking a mechanical devise that is generating and electrical signal only to produce a read out on another mechanical devise. Then there are about 5 other factors that can even throw the needle off. Mr_Dude explained very well in one of his previous posts the reasons for our speedos being off.

Cliff notes: Everyone has an opinion on what their deffinition of a 100 mph pull is. It doesn't mean there is anything wrong with their car based on their opinion of high end pull. Without a limiter a stock LO3 will go 120 to 130 depending on conditions. With a limiter it will not go past 112-115.

There is no more point in continuing this thread. Some how we have taken opinions and turned them into "somethng is wrong with your car." Please feel free to PM me with any comments or concerns.