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Discussion Starter · #1 ·
Tomorrow, it's back to the track, for test and tune, to see if I can chip another tenth or two off my E.T
I''ll have time to try different things such as timing, jetting, shift points, launching. I really hope to increase my mph a little more though.
Just about all the calculators I've tried say I should run a 12.7's. I'm at [email protected] right now
Hopefully they prep the track good so I can run my usuall 1.70 60' times.
I'll post here tomorrow with the results.
 

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Good luck,Brian and have fun. Try to check the finish line RPM to see if the converter is slipping.

_________________
'58 Morris Minor 289 S/S MM
'62 Falcon 351W "Just Falcon Around"

<font size=-1>[ This Message was edited by: Just Jim on 9/16/06 9:59pm ]</font>
 

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Discussion Starter · #3 ·
Well, I got back today from T&T and I ran the same as before at [email protected] but I had a best 60' of 1.67!
I had a pair of 82 jets for the rear I tried and MPH didn't really change much. It fell about 1/2MPH so I but the 80's back in and tried to increase timing another 2* and it REALLY did not like that!! My trap speed fell 3MPH and E.T went up to a 13.25 So I put timing back to where it was and ran my 12.8's again.
I don't know...I think I'm at my max. with this setup. I could try increasing primary jetting but doubt that would do anything.

Jim, my rpm through the traps is 5700-5800, which is about 5% converter slip, which is about normal.
I think any more gain in E.T is going to require, at least, better heads.....or my nitrous installed
 

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Congrats on the new 60ft
It sounds like something is definetly holding you back on the top end since you didn't see any improvement at the line with the better 60ft...Too bad you didn't have a bigger carb or something to try while you were there.I'm following your posts closely since I will be building my 351 in the spring and it will be very similar to yours except with edlebrock rpm heads...How do you like the XE 274 cam?How does it sound at idle?
 

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Discussion Starter · #5 ·
It sounds pretty lumpy at idle....more than what you might think with a 274* advertised duration.
I thought about unhooking the H pipe, at the track, to see if that would make any improvement.
I just think that my heads are at their limits right now....they're the biggest weak link in my setup.

JIM, what intake, carb, and gears are you going to run?
 

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How much timing are you running now?
Have you tried taking timing away? My gf's car picked up 25 rwhp when I took 4* of timing away from it (ported iron '70 heads.) Her car only has 30* of timing, and runs 1/8 mile times equal to 12 flat in the qrtr on pump gas and using a 4.11 gear. Stock ported heads are capable of much more et than you currently are running.

I seriously doubt if a bigger carb would have gained anything. If the motor is constrained by the heads, putting a bigger carb on wont help one bit (been there, done that.) The cam and shorty headers are holding the motor back in my opinion.

<font size=-1>[ This Message was edited by: kid vishus on 9/17/06 9:50am ]</font>
 

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Discussion Starter · #9 ·
I'm at 36* total timing now. That's where it seems to like it. Two weeks ago it was at 34* and took it up to 36* and that's when it ran my best of 12.85. Today, I tried two more degrees and E.T and MPH fell way off. So 36 seems to be the sweet spot for this engine.

IMO, I think it's a combination of my cam and heads that's holding me back. I've seen cars with much quicker E.T running shorty headers.
If I could change just ONE thing, right now, I would swap the heads and gain the most E.T from that change alone compared to a new cam or going longtubes.
 

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Too much cam will kill the street side of the equation. If yours is a full race car with open headers and either no exhaust or 3" with see-through mufflers w/o tailpipes, go ahead and install a significantly larger camshaft with a very tight lobe seperation... and hopefully a bump in compression ratio... along with a Victor Jr, and watch you et's go down around a half second.

If it's a street car, get the heads and your car will run as good as some of the 'race' cars using stockers.

Save your pennies. Get some heads. Save some more.... get a $300 393 crank and 302 pistons to make more cubes. When shopping for heads, you may as well shop on the larger side of the spectrum in anticipation for any future stroker buildups.


Of course, how far you can go with your current heads depends upon the quality of the port work. 95% of the port work on stock heads I've seen isn't that great.

Good Luck!
 

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On 2006-09-17 02:32, 82GT wrote:
I've seen cars with much quicker E.T running shorty headers.
And I've seen cars with stock heads also run much quicker et's. And considering I have seen as much as 25 rwhp gain by switching from shorties to long tubes, that appears to be a whole lot cheaper than buying heads to me.

Anyways, the car leaves good as evidenced by the good 60' time. What are the rest of the incremental times? That might give everyone here an idea of where the car is losing ET and be able to more accurately pinpoint what the car could use to go faster.
 

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Discussion Starter · #13 ·
Ok, here are the rest of the incrementals:

330......5.165
mph....83.23
660.....8.102
990....10.668
MPH...102.58
E.T.....12.858
 

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Discussion Starter · #14 ·
On 2006-09-17 04:49, n2omike wrote:
Too much cam will kill the street side of the equation. If yours is a full race car with open headers and either no exhaust or 3" with see-through mufflers w/o tailpipes, go ahead and install a significantly larger camshaft with a very tight lobe seperation... and hopefully a bump in compression ratio... along with a Victor Jr, and watch you et's go down around a half second.

If it's a street car, get the heads and your car will run as good as some of the 'race' cars using stockers.

Save your pennies. Get some heads. Save some more.... get a $300 393 crank and 302 pistons to make more cubes. When shopping for heads, you may as well shop on the larger side of the spectrum in anticipation for any future stroker buildups.


Of course, how far you can go with your current heads depends upon the quality of the port work. 95% of the port work on stock heads I've seen isn't that great.

Good Luck!
The only real street action it sees is when I have to drive it 20min. to the track 'cause I don't have a trailor....or truck to pull one with.
I don't want to "outgrow" my converter again. Whatever way I go is going to HAVE to match my current stall speed.
I refuse to swap another converter, by myself, on a dirt garge floor with a floor jack and stands!.....NOPE!
 

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On 2006-09-17 11:46, 82GT wrote:

I refuse to swap another converter, by myself, on a dirt garge floor with a floor jack and stands!.....NOPE!
Come on man, where's your sense of adventure?


The last time I pulled the trans out of my car it was in the driveway (dont have a garage), by myself, laying on gravel. Oh yeah, it really sucked too.

Just messin with ya. I dont blame you one bit.
 

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Discussion Starter · #16 ·
Another thing I was thinking that might be happening during the run is maybe the power valve is closing. Is that possible? I have a 6.5 PV in right now..
An engine typically goes to zero, or almost zero, vacuum at full throttle and then start going back up....correct.
Could it be hitting 6.5hg on the way back up and closing off fuel enrichment? If that was the case, I would need a bigger PV....right?
Some say go smaller on the PV but wouldn't that close even earlier?
There HAS to be something going on that's keeping my MPH 4-5 lower than what it should.
I'm happy with the the consistant 12's but the MPH is a little embarrassing especially when I race an import and beat him by a full second but his trap speeds are 10mph faster.
 

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I cant see that being an issue with your motor and carb size. It is an issue with circle track cars that are carb limited. A 2 barrel equiped circle track car will see vacuum in the upper rpm's, but it due to the carb being much too small. Couple that with the fact a lot of those guys will spin their motors around 7k rpm and it is a recipe for all kinds of unusual problems dragracers dont experiance.

You could try changing it if you want, but I dont think it will have any effect on the mph. I firmly beleive it being slow is due entirely to the small camshaft, and the shorty headers. Your heads aren't helping it any, but those heads with a bigger cam would run more mph.
 

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What size are your headers that you are using? I hane 1.1/2 headers a 306 cube and smaller heads than you have. You have my numbers to compare to. I really think it is fuel line size or your fuel pump. When i put my 351w together this winter i am looking to go high 11s or low 12s at the worst. Did you make the changes that cobrar told you to make? Did you take your sway bars off to get your 60s better
 

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This is kind of fun to play with. http://www.wallaceracing.com/etcalc.php

I know online calculators are not always the most accurate things in the world, but with this one, depeding on which of your numbers gets entered, is pretty danged close to what you are running now. Except for the 60' time, it's never close.
 
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