Added fresh bottomend (306), ported intake, and longtubes...gained just .8 mph...why?

[5spd GT]

Last season's best run was in the 1/8th mile a 8.34 at 86.22...and this year's run (with the new bottomend with 800 miles on it, longtubes over shorties, and ported intake, new clutch disc, synthetic t5 fluid, spare tire removed, plugged up the EGR which has not ever been plugged up?) I got 1/8th mile of 8.25 @ 87.01mph. All those "changes" and freshenings and just that much of a gain, not the most impressive.

I only gained 1 tenth and .8 mph. The mph gain I was more focused on...needless to say I was pretty dissapointed.

I kept the same timing (16*), same fuel pressure, and same spark plug gap from my old runs and put them "on" currently. To keep as many variables the same.

The weather was nice on both days...and I'm quite confident my driving has improved.

I do know I bent the shift fork (3rd and 4th), so I was shifting hard and a tick quicker IMO.

What do ya'll think is the reason for the "little gain"...I'm pretty sure weather/driving in this case aren't much of a factor...

I also think my times are a bit slow for what I think I'm capable of running. 3,400lb race weight, with a/c, powersteering, etc...all still on...but still I think I could do better

Your thoughts?

 

[5spd GT]

Also to add...the tightness of the new engine could quite possibly hurt, over a "loose engine" like I had before (164k).

My tach might not be that accurate...so that could help explain part of me not being as quick as I should...but that doesn't explain the little gain I got from the 306, ported intake, and longtubes.

I don't expect much from the longtubes, but the others I expect more out of it and I know they are there...

 

[mustangjoe87]

Were the R/T and 60ft exactly the same on both runs?

 

[nmcgrawj]

what about the shift points? Where those exactly the same? I'd imagine that with the ported intake, it would want to rev a little higher than before...

 

[5spd GT]

Were the R/T and 60ft exactly the same on both runs?

Reaction time doesn't reflect my E.T. or mph change. I could sit at the lights for 30 seconds and still run the same time technical.

60ft was very very close. Within .0x of the time...I ran a few more times with the same mph results.

Nate- Well the ported intake helps the whole powerband a bit, more so in the 3,500rpm and up band...but I shifted them at 5,900 on both runs (this year, last year)...according to my stock tach. It doesn't seem to want to "go" as quick as the earlier rpms, compared to when I get up to 6k. I kind of do it by how it feels/hears...

I just figured there would be more of a significant difference than .5mph from those changes...

Thanks for the replies guys!

Any others?

 

[DMAN302]

At 6000 on my stock tach..my autometer was registering 4800!!!!

 

[5spd GT]

At 6000 on my stock tach..my autometer was registering 4800!!!!

Wow Derek, did you or a previous owner install white faced guages...or was the guages never touched from the factory.

My guages were installed by the previous owner, but honestly it seems to be fairly accurate when I compare gear/speed and idle speeds to others:s As it is reved it could differ though

 

[04sleeper]

David,

I have experienced similar differences between stock Tach's and Autometer Tach's. It was off by anywhere between 600-800 RPM's. Not quite as much as DMAN's.
The stock tach responds slower than the Autometer in reving up and coming down.
It was almost like the stock tach was trying to play catch up to the Autometer and kept getting further and further off the higher it went.

I would invest in either a good shift light, like a Raptor or similar, or a better tach to give you more consistent results.

Also even though the other things are the same, (ie timing, fuel pressure, etc...) the engine has changed so it will respond different.

I think there is still more in it, it just has to be fine tuned. Keep trying different fuel pressures and different timing adjustments and different shift points, etc... to get that new combo dialed in.

And it will make slightly more power after the motor loosens up a little. It will also run cooler too.

 

[NC85]

How about you post up an old timeslip and your new one. Telling us you sixty'd .0x difference from your last run is bad info. What tires are you running?

Sounds like you need a tach, a new tranny, and some more seat time at the track with the new combo.

You should be well in the 7s with a slick.

 

[DMAN302]

Tach was stock and untouched...reason for it..no idea. The difference was a shock and very interesting...explained why she would pull so cleanly to 6000 where everyone else stock was falling off at 5

 

[5spd GT]

How about you post up an old timeslip and your new one. Telling us you sixty'd .0x difference from your last run is bad info. What tires are you running?

Sounds like you need a tach, a new tranny, and some more seat time at the track with the new combo.

You should be well in the 7s with a slick.

Old: New:

60ft - 1.94 60ft - 1.95 (worse but still .0x like I said.)
330ft - 5.44 330ft - 5.39
1/8 E.T. - 8.34 1/8 E.T. - 8.25
1/8 MPH - 86.22 1/8 MPH - 87.01

So how can you comment on what I should run when you do not know my cam specs? I could have 450"/456" lift with 210* duration on both sides for all you know

Nitto Drag Radials with no burnout, 16psi.

My driveshaft rubs the bottom of my car under hard acceleration off the line.

I'm not going to run slicks, this is my daily driver.

 

[5spd GT]

David,

I have experienced similar differences between stock Tach's and Autometer Tach's. It was off by anywhere between 600-800 RPM's. Not quite as much as DMAN's.
The stock tach responds slower than the Autometer in reving up and coming down.
It was almost like the stock tach was trying to play catch up to the Autometer and kept getting further and further off the higher it went.

I would invest in either a good shift light, like a Raptor or similar, or a better tach to give you more consistent results.

Also even though the other things are the same, (ie timing, fuel pressure, etc...) the engine has changed so it will respond different.

I think there is still more in it, it just has to be fine tuned. Keep trying different fuel pressures and different timing adjustments and different shift points, etc... to get that new combo dialed in.

And it will make slightly more power after the motor loosens up a little. It will also run cooler too.

I think the timing is where I need to look at in finding a bit more power. It was just kind of funny (if the spare tire/jack wasn't taken out) that I would have ran very close to my last times, exactly.

Yeah, I know there is more in it...next time your down...I'll let you drive it and see what you think If I can get the job I'm looking for this summer, many of those additions will come...

 

[04sleeper]

I think the timing is where I need to look at in finding a bit more power. It was just kind of funny (if the spare tire/jack wasn't taken out) that I would have ran very close to my last times, exactly.

I know where you are coming from. It is going to take a little time to get it dialed in. I wouldn't worry about it too much.

Yeah, I know there is more in it...next time your down...I'll let you drive it and see what you think If I can get the job I'm looking for this summer, many of those additions will come...

Sounds good.

I'll have to hold you to that next time I am in your neck of the woods. View attachment 474029

 

[MustangGT92]

had you tried fuel pressure regulator...make sure you not getting to much fuel....maybe even your throttle body...make sure its not to open or even opened enough...

 

[NC85]

So how can you comment on what I should run when you do not know my cam specs? I could have 450"/456" lift with 210* duration on both sides for all you know

I don't care about your cam specs. You could have a stock cam for all I care. In fact, I'm basing my opinion on what your car is capable of with an 87mph trap speed.

You have some issues....more driver than car.

 

[jjd975]

There is a chance that what you see is what you get.

If the old shortblock wasnt bad, theres no real reason to think that a refresh will gain you a lot of power. Not sure what all you did to the shortblock, but again just going to a 306 from a 302 doesnt mean a lot.

Odds are the ported intake and headers are what made the power. And again, no real reason to think that a ported Performer will help all that much. Tons of guys are getting it done with AFRs and non-ported Performers.

Not being a jerk, just some points to really think about.

Up side is you have only been out with the car one time. Tons of ET left in 60' alone.

Your timing sounds right, might add 1-2 degrees max.

What RPM do you cross the line at? Whats the duration of the cam? I would say 5800-6000 would be best shift point, just need a real way of knowing what you shift at. Get a real tach or shift lite.

IMO your doing pretty damn good. 87 @ 3400 lbs. You figure with just a swap to some Welds (big-n-lils) you would be running over 88 with ease. I know I gained 1.5 mph with mine (in the 1/4). You have 7 second car, just not the slip.

 

[5spd GT]

So how can you comment on what I should run when you do not know my cam specs? I could have 450"/456" lift with 210* duration on both sides for all you know

I don't care about your cam specs. You could have a stock cam for all I care. In fact, I'm basing my opinion on what your car is capable of with an 87mph trap speed.

You have some issues....more driver than car.

Interesting, since I pull better times than my friends with their own cars.

 

[5spd GT]

There is a chance that what you see is what you get.

If the old shortblock wasnt bad, theres no real reason to think that a refresh will gain you a lot of power. Not sure what all you did to the shortblock, but again just going to a 306 from a 302 doesnt mean a lot.

Odds are the ported intake and headers are what made the power. And again, no real reason to think that a ported Performer will help all that much. Tons of guys are getting it done with AFRs and non-ported Performers.

Not being a jerk, just some points to really think about.

Up side is you have only been out with the car one time. Tons of ET left in 60' alone.

Your timing sounds right, might add 1-2 degrees max.

What RPM do you cross the line at? Whats the duration of the cam? I would say 5800-6000 would be best shift point, just need a real way of knowing what you shift at. Get a real tach or shift lite.

IMO your doing pretty damn good. 87 @ 3400 lbs. You figure with just a swap to some Welds (big-n-lils) you would be running over 88 with ease. I know I gained 1.5 mph with mine (in the 1/4). You have 7 second car, just not the slip.

Yeah, the old shortblock had 164k on it...so if I were to guess I lost some compression...but I'm sure it will slightly increase as the miles increase.

According to my cam specs: powerband is 2,600-5,600...I should be shifting about 5,900-6,000 if I were to guess.

Yeah, the track I went to isn't a 1/4 track...1000ft. track.

My 60ft would improve if I did a burnout and my driveshaft wouldn't rub off the line...

Thanks for the response!

 

[2002BLGT]

Old: New:

60ft - 1.94 60ft - 1.95 (worse but still .0x like I said.)
330ft - 5.44 330ft - 5.39
1/8 E.T. - 8.34 1/8 E.T. - 8.25
1/8 MPH - 86.22 1/8 MPH - 87.01

So how can you comment on what I should run when you do not know my cam specs? I could have 450"/456" lift with 210* duration on both sides for all you know

Nitto Drag Radials with no burnout, 16psi.

My driveshaft rubs the bottom of my car under hard acceleration off the line.

I'm not going to run slicks, this is my daily driver.

timeslip makes no sense what so ever .... with a 60ft in the 1.9s and turning 88 mph in the eighth.....is the car sideways past the 60ft .because your 330 time should be a little closer to a 5.1 or so unless you are doing a crap load of spinning which all in all is going to make your times so inconsistent they aint worth worrying about anyway .....

 

[5spd GT]

timeslip makes no sense what so ever .... with a 60ft in the 1.9s and turning 88 mph in the eighth.....is the car sideways past the 60ft .because your 330 time should be a little closer to a 5.1 or so unless you are doing a crap load of spinning which all in all is going to make your times so inconsistent they aint worth worrying about anyway .....

I didn't notice any spinning, it wasn't spinning...maybe a few wheel hops.

This is 3,400lbs...cars differ. 210lb driver.