Bigger Headers, Slower Car

[1966Canuck]

I would check resistance at the Flux-Capacitor ?

 

[RemCharger]

didn't read all the post,
#1 it's lean
#2 & needs header extensions, 15" to 18" worth

1st give away was
it's even slower when you took the air cleaner off
leaned out even more
(need a better air-cleaner element too (like K&N Gauze), tune to that also)
you need to read the plugs
may need a timing change now too

View attachment 1692448

sometimes a longer 'smaller diameter' tube, will aid in low end torque too
the bigger tube will flow better on the top, need to address
what's going on down low too
may even affect how you converter stalls

good luck

Well stated. And it's a 4 spd

 

[padam]

Oddly enough, the headers are supplied with 3-1/2 to 2-1/2 reducers.

I got 18” 2-1/2 pipes and bolted them up this evening. Left side lays against the cross member but it’s good enough to try it. This should make some kind of difference.

I ran it for a couple minutes and it sounds like it has mufflers.

Tomorrow I have to take loose the right torsion bar and re-set it. I had it off to swap the headers and when I reinstalled it I tightened the shaft nut with the suspension unloaded, and now it won’t adjust down far enough.

I’m planning on TnT Friday night. I’m going to try it first with the 2-1/2 extensions. I also need to try some things to improve my reaction times.
I’ll be lucky to make 4 passes.

Then I have a UMTR points race on Saturday.

 

[padam]

I would check resistance at the Flux-Capacitor ?

I have a K&N flux capacitor, good for an extra 20 hp

 

[PRHeads]

The 2-1/2” reducer/extension doesn’t sound like the hot set-up to me, but it’s basically free to try since you already have it.
But I am curious to see how it plays out.

 

[padam]

The 2-1/2” reducer/extension doesn’t sound like the hot set-up to me, but it’s basically free to try since you already have it.
But I am curious to see how it plays out.

You’re right about that.

I got out Friday and Saturday.
There wasn’t much change in performance, maybe .05 improvements in ET, but hard to pin it on anything in particular.

In trying to analyze it, I think that with my current setup I’m right on the verge of clutch slip at launch. If the clutch slips for 1/2 second it makes a big drop in ET. It’s very hard to maintain that setup though.

The air was pretty funky this weekend too, so tough to compare.

I’m half Polish and half Italian.
The dumb pollack in me just wants to go faster every time. The calculating Italian wants to play the numbers and win races.

And who says you can’t teach an old dog new tricks?

I spent Friday night learning to leave on the bottom bulb. I’ve got a long way to go, but I learned enough to win the final in UMTR Street Stick last night.

I’m not sure where to go from here as far as the tune on the car. I think next chance I get I’ll try to read the plugs to get an idea what my mixture is like, and go from there.

 

[33 IMP]

Nothing wrong with trying to go faster.....as long as it doesn't keep you from winning races, lol.

 

[padam]

 

[BrettL]

1964 413 Block .030 over

906 Heads, milled .100, stock size valves.
Gasket matched intake ports and bowl area ported to the DC templates.

Compression ratio is roughly 11:1

Lunati Hydraulic Cam Part# 10230906
In Ex
.509 .534 Valve Lift
235 245 Duration at .050
Rhoads Hydraulic Lifters
Lunati 73815 Single Valve Spring W/ Damper

Edelbrock Torker intake.
Quick Fuel 850 race carb (OOTB tune).

Ignition system is an MSD 6AL-2

My personal experience was similar when I went to the 2” primaries the torker intake has a higher rpm range. it was recommended to me to switch to the edelbrock Rpm manifold and I got all the low end torque back and then some and it still performs with in my desired Rpm range. Just a thought. I had the Torker 2.

 

[padam]

 

[Rebelrouser]

I switched out my old Hooker headers with 1.75" primaries and 3" collectors for a set of Dougs headers with 2" primary 3.5" collectors.
Neither of these have collector extensions.

I got out to the track Friday night, and found that the car slowed quite a bit
60' 1/8 1/4
Before 1.621, 7.623 90.20, 11.985 112.30
After 1.685, 7.687 89.70, 12.089 111.06

I think it bogged a little of the line, so matbe torque is down.
Later I removed the air cleaner/filter, and it seemed to slow a little more.
From this I am thinking it may be running lean with the new headers.

Can anyone recomend a move to get back the lost power?

From my experience the headers are too big, back pressure is not the issue gas velocity in the tubes are the issue. When I select of build a set of headers, I use engine simulation software to select tube size and length. When I build a set, I use pipemax software. Most sets I build are step headers, even race engines start a 1 7/8 and finish at 2 1/8 on most mopar big blocks. Have built 800HP combinations for NSS

 

[fourgearsavoy]

View attachment 1694719

Nice job Paul ! Feels good hitting every gear perfectly and getting a win to prove how good you are at rowing the gears. In the early 90's I went 11 rounds for the win at 42 running in Pro-ET . What a great feeling that is.
Gus

 

[padam]

Nice job Paul ! Feels good hitting every gear perfectly and getting a win to prove how good you are at rowing the gears. In the early 90's I went 11 rounds for the win at 42 running in Pro-ET . What a great feeling that is.
Gus

Wow that’s a lot of shifting!

What were you driving back then? My friends growing up and I raced a little at 42 back then, street cars. That’s where I caught the bug for sure. I had the same car but it was still green.

Different era for sure. To put it in perspective, I only had to win 4 rounds, but still didn’t finish until 10:39 pm. I don’t know why everything takes so much time now.

 

[fourgearsavoy]

I've had the same Savoy same paint for 33 years and it's always been a stick car. I always drive it to the track and most of the time I can still drive it home. Yeah back in '96-'97 eliminations started at 1:00 and things went pretty smooth because I was home before dark that day. I was running mid 11's back then.
Gus

 

[fourgearsavoy]

Before the 493 still running 12's

 

[padam]

Before the 493 still running 12's

View attachment 1695136

That’s back before they changed the track right?

 

[496 polara]

Every time I have run 2" headers I have slowed down.Tells me I don't have enough motor,stall,or gear. Or all three lol.

The first two applications were heavy street cars and it just killed the bottom end. One car I went to more gear and the other car back to the smaller headers.

My pig of a 72 duster with a 440 ( 8.5-1 with an xe274 cam and cnc ported stealth heads) has 2" headers and it is a turd with 3.55 gears and a stockish (in the car when I bought it) converter. Kinda wish I had left the trip y headers on until I get a bigger motor. The Tti 1 3/4 headers would probably help this motor a lot but buy once and cry once. I got the 2" for the planned 505 motor upgrade.

Too hot to drive it now with no a/c so it doesn't bother me a lot at the moment. I need to get that stroker shortblock together before the fall!

 

[oldbee]

I’ve read & reread and don’t see it——- paint ur extensions with a light stripe of white paint on one side. After a couple runs, see where the paint discoloration starts & chop the extensions at that point.(if I remember correctly). My 18” extensions had about 4-6” cut off them. This was a long time ago!!! May not be pertinent anymore.

 

[33 IMP]

I’ve read & reread and don’t see it——- paint ur extensions with a light stripe of white paint on one side. After a couple runs, see where the paint discoloration starts & chop the extensions at that point.(if I remember correctly). My 18” extensions had about 4-6” cut off them. This was a long time ago!!! May not be pertinent anymore.

If I remember right I saw that paint stripe trick debunked as an old wives tale.
Might have been on the engine masters header extension episode.

 

[33 IMP]

I've got three cars with 2" headers, and probably too-big exhaust systems behind two of them. (Two big blocks, and a small block)
Two of the cars have custom headers for oddball chassis, and I'm not gonna spend $1500 for another set of custom headers, to find out if smaller is faster.
The other set is absolutely ancient, but still functions, and it's just a bracket car, spending even $500 for smaller headers to MAYBE go a little faster, doesn't seem like a good plan......