tunnel ram results

[MadBill]

Is the car street driven a lot, a little or none? It's easier said than done and I'm too lazy to run the sim for a more exact number but my SWAG is that bumping the CR to 13:1 would net you 40 HP and lb-ft. At 1,600' elevation you could probably still get by in limited street duty with a mix of 93 and race gas.

[F-BIRD'88]

IMHO you will get more bang for the buck out of a hood scoop and finalizing the carbs for that than new bigger carbs.

A big chin spoiler under the front bumper can help too.
It will pull the front end down ( out of the air) at speed.
Better areo, better speed.

Gears: This car should of had a Turbo trans all along.
Especially now with the tunnel ram. Got any converters you can try out?

Play with valve lash......

"Small carbs" will want (added) plenum height

[F-BIRD'88]

The cam may need to be moved 'cause of the relative low cr.

[Steve.k]

As for results none yet. Just got engine in car. The old setup was a single 1050 on chi 3v 400 intake. That setup made 650.6 hp at 6700 this change made 703.8 at 6700. The tq from 3500 to peak @ 5100 started at 20ftlb more then peaked at 35ftlb more at peak 5100

[prairiehotrodder]

My best timeslip :

1.428 60'
4.042 330'
6.262 1/8 and 110.33 mph
8.193 1000'
9.846 1/4 ET at 135.48 mph.


On the friday night with no traction compound it went 10.005 at 136.5

The motor wants lots of timing. Like around 39 or 40 and it also wanted more fuel. As stated in my other threads the carbs were factory jetted at 80 / 90 so thats how i started out. I went to 84/90 and it went faster. I just changed the front jets but will likely re-jet to 82/92 to even them out. Maybe next time i'm at the track i will plug the PV and try 92/92 and see what happens. The car gets street driven a little. Never very far.

[statsystems]

My best timeslip :

1.428 60'
4.042 330'
6.262 1/8 and 110.33 mph
8.193 1000'
9.846 1/4 ET at 135.48 mph.


On the friday night with no traction compound it went 10.005 at 136.5

The motor wants lots of timing. Like around 39 or 40 and it also wanted more fuel. As stated in my other threads the carbs were factory jetted at 80 / 90 so thats how i started out. I went to 84/90 and it went faster. I just changed the front jets but will likely re-jet to 82/92 to even them out. Maybe next time i'm at the track i will plug the PV and try 92/92 and see what happens. The car gets street driven a little. Never very far.

You engine is over carbed. Do the math. You need smaller carbs.


















Ok, now that I have the smart ass portion of my answer out of the way...I'm not at all surprised you needed that much timing. Read the plugs and give the engine what the plugs tell you they want. It's just a number.

EDIT: if it's lean, why just give it fuel on the primaries? That doesn't make sense. If it's lean, add some to both ends until it slows down and then adjust it from there.

The airflow through the secondaries is the same as the primaries.

[MadBill]

When using carbs of unknown history, I've often seen benefits from separately tuning with just the primaries, then reconnecting the secondaries and re-tuning, changing only the secondary jets. One ~ 400 HP Quadrajet-equipped circle track engine picked up 13 HP this way while leaving the overall AFR unchanged.

[PRH]

I don’t know how many different Weiand TR’s there are for a BBC with square port heads, but Ive tested a couple motors with them and they had no top end at all.
Same for the BB Mopar one.

The ones I ran had the tops of the runners in the plenum shaped like a “D”.

They made I nice boost in the mid-range numbers, but were pretty much done by 62-6300.

The airflow numbers through the motor just stagnated in that 6000rpm range, and if hadn’t already run the motor with a single carb manifold and knew the valvetrain wasn’t an issue, I would have thought it was having some valve control problems.

Using a few easy formulas that were in the SF flow bench manual, it appeared the BB Mopar TR was tuned to about 5900rpm on one particular combo.

While the TR did make more peak power than the single 4500 carb, at 7000 the 4500 combo was over 100hp better.

My suggestion would be to try a more race oriented TR manifold before I changed much else...... or figure out a way to keep the motor below 6300rpm.

[prairiehotrodder]

I don’t know how many different Weiand TR’s there are for a BBC with square port heads, but Ive tested a couple motors with them and they had no top end at all.
Same for the BB Mopar one.

The ones I ran had the tops of the runners in the plenum shaped like a “D”.

They made I nice boost in the mid-range numbers, but were pretty much done by 62-6300.

The airflow numbers through the motor just stagnated in that 6000rpm range, and if hadn’t already run the motor with a single carb manifold and knew the valvetrain wasn’t an issue, I would have thought it was having some valve control problems.

Using a few easy formulas that were in the SF flow bench manual, it appeared the BB Mopar TR was tuned to about 5900rpm on one particular combo.

While the TR did make more peak power than the single 4500 carb, at 7000 the 4500 combo was over 100hp better.

My suggestion would be to try a more race oriented TR manifold before I changed much else...... or figure out a way to keep the motor below 6300rpm.

if thats all true, it makes sense. I bought this t-ram used and its been heavily ported inside. It is the #1985 and yes it has the D-shaped ports.

[prairiehotrodder]

Just not sure i understand your second last statement about the t-ram making more peak power but the 4500 being 100 hp better at 7000 rpm ??

[PRH]

After 62-6300rpm, the power drops off a cliff with the Weiand TR, whereas the curve was much more gradual after peak with the single carb set up.

Going from memory......

On the build I was referring to, the TR combo peaked at 680hp at about 6k, but was down to about 530hp at 7k.
With a ported TG 4500 intake and 1150 carb the motor made a peak 650hp at 6500, and was still about 630hp at 7k.

[F-BIRD'88]

PrairieRodder: Did you happen to have made any cross section area measures of the ported Weiand manifolds runners?
The others may have a point. Especially if the runners tuned length is a bit too long for top end combined with not big enough cross section area.
The good news is you can modify this. Also , do not be afraid to play with the plenum top. Including making your own custom plenum top. I like the Edelbrock race tunnel rams better too. Too bad your Kijiji deal on the Eddy Victor Ram BBC intake fell thru.


is the porting on your manifold done right with a consistent cross sectional area, or with a suitable taper from entrance to exit points.
You'd want to avoid a bottle neck right in the middle of the runners
( hardest part to get at when porting)

Things to look at.

[F-BIRD'88]

After the carbs are finalized and a forward facing scoop is added I'd start messing with plenum volume and height adjustments.

[PRH]

As an example of how it should work, when the TR is more suited towards the top end:
Mopar 540 with Indy 440-1 heads.
With a 440-2 manifold, the 4150/4500 adapter and an 1150 carb the motor made peak tq @5300, peak hp @6800.
Installed a ported Indy TR with 2-1050’s on it and the tq peak moved up to 5700 and the peak hp to 7300.
The TR made 20 more tq, 43 more hp.
At 7300 the TR combo was 54 better.

[prairiehotrodder]

Is the edelbrock Victor ram 2-R # 7075 any better than the Weiand 1985 ? Seems like if i was gonna upgrade tunnel rams the thing to do would be to jump right to the victor tunnel ram #7085. It only has a dominator top so i would need adapters to run my 4150 carbs and all the adapters i see are 2" thick which would add alot more plenum volume to an allready huge plenum and possibly overkill manifold. I'm not going to switch carbs anytime soon. I like the looks of the Weiand alot more than the edelbrocks and now that i'm making some progress with these carbs i'm happy to keep them for awhile.

I've tried 3 different cams in this motor and all gave about the same results. I'm not convinced that I've reached the limit of these heads either. I'd maybe consider going to 4.30 gears but if the tunnel ram is running out of breath then changing gears will make it worse. I'm pretty sure the car would like a 3 speed. If i had a built turbo 350 that i could toss in that would be an interesting test. The Turbo 400 would require a different driveshaft and tranny crossmember. I sure appreciate all the idea's on Speedtalk. Don't know what i'll do next but not anything exspensive. An 8-71 blower would also be interesting to know what would happen if i just bolted in on to my engine as is with the carbs i allready have.
Brian