Tunnel ram or no tunnel ram...

-
Miszny said:
This is Indy tunnel ram without cover after initial cleaning. I was thinking about spacer under top cover but this is for future experiments. No room for anything in current setup.
I was asking about filling that void based on this plenum design.

View attachment 1716181643

View attachment 1716181644
Click to expand...
OK sorry I misread this reply. So what i have in that cavity is sloped in a similar way but, more importantly let's not assume that Indy designed this 'correct' either. You won't see all this 'correct' executed in any new tunnelram plenums.
 
MOPARMAGA said:
View attachment 1716182029

View attachment 1716182031

View attachment 1716182032

View attachment 1716182033
This was a lot of work, but the work paid off as this standard port tunnel ram only fell off from peak 5800 to 6800, 60 HP.
Prh told me he tested this same manifold untouched and it was over 120 HP.
It's ugly on the outside but inside it's beautiful.
I love burr finish, my 1st burr finish too.
Click to expand...
It took me a while to find this pic again, I admire your efforts! What is the cross-section of the runner in the plenum area? What is the runner length? What is the trajectory into the head? Does it match what the engine wants? Etc. Also when it's done how ideal is the height in relation to the scoop you want to use? That's why I offer that if a guys willing to do the work, there are better foundations to start with that may not be any more expensive in base material and/or time. Can you explain differently what you meant by the 'only lost 60HP'? Whereas another manifold was 120? What RPM theoretically should the 'long-block' peak at? THANKS!
 
ValiantS said:
It took me a while to find this pic again, I admire your efforts! What is the cross-section of the runner in the plenum area? What is the runner length? What is the trajectory into the head? Does it match what the engine wants? Etc. Also when it's done how ideal is the height in relation to the scoop you want to use? That's why I offer that if a guys willing to do the work, there are better foundations to start with that may not be any more expensive in base material and/or time. Can you explain differently what you meant by the 'only lost 60HP'? Whereas another manifold was 120? What RPM theoretically should the 'long-block' peak at? THANKS!
Click to expand...
I'll try to answer all of this as best I can.
I don't even know if I can properly.
I'll have to go out and measure stuff on the tunnel ram though to get the answers.

With the scoop, I'm going to make my own hood and integrated scoop. As soon as I get the engine in the car, I'll have an idea on that.

Prh asked mentioned to me before I had Dyno tested my engine my style of tunnel ram on a very similar build started to lose power after peak. His tests I believe were from 5800-6800.
He told me the manifold he tested dropped 124 HP from peak rpm to 6800 rpm.
We tested mine with the work I did from my also peak 5800 but it only lost 60 HP by the time it reached 6800.
That's the best I can explain it. But I realize it's 2 different dynos, 2 different engines..I don't know all of the specs of the engine he tested except same ci, pretty close cam, intake manifold and 2 850 carbs. I imagine my 2 inch merge spacers help a little to keep the plenum volume higher.
I think my long block should peak 57-5800.
Small cam 264-268 .660-.674 lift.
Trickflow 240s with gasket match blending and port matched intake to head.
 
Let me clarify my test results:

Low deck 452 w-original stage 6 heads with mild porting, std port window(300cfm).
UD [email protected] roller, 12.5cr.

Tested from 4700-7300.

Weiand TG4500 with non-HP 1150 carb-
556tq@4700
560tq@5000(peak)
650hp@6500(peak)
623hp@7300

Install port matched Weiand TR with 2 x 650DP Demon carbs-
585tq@4700
590tq@4800(peak)
676hp@6200(peak)
563hp@7300

Both combos were 639hp@6800.
After 6800 the TR combo just nosed over.
The single carb combo lost 45ft/lb from 6800-7300
The TR combo lost 88ft/lb from 6800-7300

Single carb combo continues to show increases in air flow all the way to 7300.
TR combo has air flow increasing to 6700, then shows slight drop in air flow from 6700 to 7300.

These are the results from consecutive pulls on the same day, about an hour and a half apart.
 
Last edited:
PRH said:
Let me clarify my test results:

Low deck 452 w-original stage 6 heads with mild porting, std port window(300cfm).
UD [email protected] roller, 12.5cr.

Tested from 4700-7300.

Weiand TG4500 with non-HP 1150 carb-
556tq@4700
560tq@5000(peak)
650hp@6500(peak)
623hp@7300

Install port matched Weiand TR with 2 x 650DP Demon carbs-
585tq@4700
590tq@4800(peak)
676hp@6200(peak)
563hp@7300

Both combos were 639hp@6800.
After 6800 the TR combo just nosed over.
The single carb combo lost 45ft/lb from 6800-7300
The TR combo lost 88ft/lb from 6800-7300

Single carb combo continues to show increases in air flow all the way to 7300.
TR combo has air flow increasing to 6700, then shows slight drop in air flow from 6700 to 7300.

These are the results from consecutive pulls on the same day, about an hour and a half apart.
Click to expand...
Thanks, I guess I was way off. My memory is junk. Thank you.
 
I decided if one is good, two is more better.

20230601_191406.jpg
 
Miszny said:
This is Indy tunnel ram without cover after initial cleaning. I was thinking about spacer under top cover but this is for future experiments. No room for anything in current setup.
I was asking about filling that void based on this plenum design.

View attachment 1716181643

View attachment 1716181644
Click to expand...
I was looking to see if I posted my Modman "tunnelram" on this site and I found this older thread. I'm not sure if you read in my earlier response to you that I do have a downward slope in these cavities to avoid puddling. Further, Indy's design of this plenum and runners is not terrible but it's not ideal.
 
rumblefish360 said:
The super short runners scream high rpm.
Click to expand...
On a 486" CID engine the 5" runner put this HP peak about 7000RPM. I added about 1.5" in runner length over a production Modman. Take a closer look at most single plane intakes from various manufacturers, especially the center runners!
 
ValiantS said:
On a 486" CID engine the 5" runner put this HP peak about 7000RPM. I added about 1.5" in runner length over a production Modman. Take a closer look at most single plane intakes from various manufacturers, especially the center runners!
Click to expand...
What cylinder heads and camshaft duration to get peak up there ?
 
MOPARMAGA said:
So your engine you have now, did I read it's just a really well built 400 block, no fill ?
Click to expand...
1973 400 block. Magged/sonic checked. It was Hardblocked to the bottom of the 'freeze plugs'. It had alloy caps, bushed lifter bores, 1960ish bobweight. 4.0" Crower crank, 2.1 journal 6.700" BME rods.
 
11-1 might be technically low for the cam but I wouldn’t give a crap since it’ll run on pump gas and like race fuel at the track a bit.

I have indeed noticed the runner lengths and have measured them on most of my intakes. Single plane only. MP-W2 on the shelf w/some markings. Plenum depth as well.

IMG_1840.jpeg
 
rumblefish360 said:
11-1 might be technically low for the cam but I wouldn’t give a crap since it’ll run on pump gas and like race fuel at the track a bit.

I have indeed noticed the runner lengths and have measured them on most of my intakes. Single plane only. MP-W2 on the shelf w/some markings. Plenum depth as well.

View attachment 1716196069
Click to expand...


What are the measurements Rob. Old people can’t read those.
 
rumblefish360 said:
7.125 on the (*IIRC, the #1) runner
3.579 on the plenum
Click to expand...
Those 4 short runners scream high RPM! Separately, what RPM is considered 'high'? You should know I'm just kidding with you but it helps make some points which is for us all to to consider. With tunnelrams distribution is generally better, plenums are bigger, line-of-site alignments. All these are worth power which will offset any 'losses' in a shorter runner going down the track.
 
ValiantS said:
Those 4 short runners scream high RPM! Separately, what RPM is considered 'high'? You should know I'm just kidding with you but it helps make some points which is for us all to to consider. With tunnelrams distribution is generally better, plenums are bigger, line-of-site alignments. All these are worth power which will offset any 'losses' in a shorter runner going down the track.
Click to expand...
High rpm to me is 1000 rpm over peak power but maybe that's just me being afraid of breaking something and not being able to play again
 
I am thinking a B motor, long duration/wide separation angle cam, Max Wedge heads and short runner tunnel ram for my Bonneville plans. Kill some torque and more power up high.
 
You must log in or register to reply here.
-

Back
Top