Tunnel Ram vs single carb 1/4 mile results

[HICKL]

11 months ago, I went to Houston raceway park, it was about 50 degrees and I was running my performer rpm intake with a holley 750 dp. The weekend I went back with my tunnel ram and two holley 450's. Was about 68 degrees this time for whatever it's worth.

 

Check out my times.

 

Single carb: 9.611 1000 ft, 11.516 1/4 @ 118.41 mph

tunnel Ram: 9.611 1000 ft, 11.515 1/4 @ 118.42 mph

 

I could not believe how close my times where, especially being a 5 speed car and all the other factors that come into play.

[grumpyvette]

I find that to be amazing, not so much due to the intake change but to have that consistancy over that time period (11 months) REGUARDLESS of the intake swap, and Id bet theres MORE potential left in the T-ram combo

[HICKL]

I'm sure there is. I meant to play with the timing a bit, but the track got busy and I was also driving a buddies car. Was there for 4 hours and only did 3 passes in mine.

[dr_hunt]

I am a little suprised that you didn't pick up more mph and a little ET. Sounds to me like you need some tuning.

[HICKL]

I am a little suprised that you didn't pick up more mph and a little ET. Sounds to me like you need some tuning.

 

 

I'm sure I do, I literally bolted this thing on, made a few adjustments to make it idle and have just been driving it. Seat of the pants, it felt pretty good, but this was my first test run.

 

The air cleaners that came with my scoop are cheap junk and probably don't flow very well. I meant to pull them out for a pass, but didn't get enough passes to do anything.

[dr_hunt]

My guess is that it's needing more fuel, you would be suprised how well tunnel rams fill the cylinders.

 

Back years ago in the 70's I actually removed the jets from my two 650 holley DP's on my tunnel ram and it ran faster!! Motor was a 355 12.5:1 comp, crower solid cam, extensively ported 292 angle plug heads in a ford pinto.

[HICKL]

It is on the lean side for sure. I need to jet it up, but need to pull one carb apart as I forgot what size are in them. I have been lazy this year with the car and have had the "if it ain't broke don't fix it" attitude.

[dr_hunt]

Well, typically with a TR you don't get good carb signal in the lower rpm range. Today with the booster design, that is not as much of a problem as it was back in the days. LOL. Just watch the plugs and jet accordingly.

[HICKL]

I definately need to spend some time messing with this thing. Looking at my 1/4 mile trap speed and using some of the hp calculators, it seems that I may be leaving a lot of hp on the table. I wish I had desktop dyno so I could play with my setup and see what it should produce on paper.

[grumpyvette]

ID EXPECT TO SEE ABOUT A 15-20 HP ADVANTAGE ON YOUR combo, with a properly tuned tunnel ram vs a good single carb. With the components you’ve selected PROVIED you run open headers and have about a 19-21" slightly tapered collector on the headers to further increase scavenging. Id suggest going from collector dia. on the header exit to 1/2" smaller dia. at a 20" length exit with a slip on or bolt on collector extension you can cheaply fabricate.

Its a small point, but frequently worth the effort with a tunnel ram to get the full ram effect on the intake.(what goes in needs to get SUCKED out with negative pressure wave tuning for max efficiency) the extra collector length tends to lower the rpm,s of and widen the torque band a bit.

Post your current parts selection in case I missed any changes and ILL run it thru my software dyno, to get more detailed info.

 

http://www.streetrodderweb.com/tech/0703sr_fabricating_tapered_cones/index.html

[HICKL]

Dart Sportsman II cast iron heads, 64cc.

383 stroker kit, should be around 11.0:1 according to Eagle.

Crane Cam grind # F-280-2

http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=114681&lvl=2&prt=5

 

Running Block hugger headers that merge into a 2 1/2" single for about 2 foot then dump out thru a cut-out for track use.

 

Tell me what else you need to know and I will answer as well as I can.

 

I don't know what the flow numbers are on my heads, but I may be able to find something on the web if you need it.

 

Thanks Grumpy

[grumpyvette]

Dart Sportsman II cast iron heads, 64cc.

383 stroker kit, should be around 11.0:1 according to Eagle.

Crane Cam grind # F-280-2

http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=114681&lvl=2&prt=5

 

Running Block hugger headers that merge into a 2 1/2" single for about 2 foot then dump out thru a cut-out for track use.

 

Tell me what else you need to know and I will answer as well as I can.

 

I don't know what the flow numbers are on my heads, but I may be able to find something on the web if you need it.

 

Thanks Grumpy

 

I remembered the heads and cam,(we had a long thread on those) and Ive looked up most of the other components in past posts ,but for some reason I thought you upgraded the headers by now to full length versions

[HICKL]

I remembered the heads and cam,(we had a long thread on those) and Ive looked up most of the other components in past posts ,but for some reason I thought you upgraded the headers by now to full length versions

 

 

I had thought about it, but read a long thread a while back and it seems like you were negating the overall gain so I have not bothered with it. May have been on more of a stock motor, don't remember the details. As far as I know, there is not really a bolt in set, so it is a project. Don't mind doing it if the gain will show up on the 1/4 mile!

[grumpyvette]

the gains of a low restriction 3" dual exhaust combined with a good set of full length headers won,t be huge over shorty headers and your current 2.5" exhaust in measurable HP, but it will produce a measurable gain in both hp and tq , over MOST of the rpm band (especially above about 4500rpm), Id expect about 20hp in peak numbers and 10-12 over most of the rpm band

in my opinion thats well worth the effort.

 

bunch of dyno info but in most cases long tube headers show more mid and upper rpm hp

 

http://www.lgmotorsports.com/gallery/thumbnails.php?album=3

[HICKL]

I have been playing with 1/4 mile/hp calculators to try and estimate my hp. Based on 1/4 mile speed or et, I have seen results from 360 flywheel hp to 460 flywheel hp to net an 11.50 or 118.5 mph on a 2850 lb car. Can anyone point me to one that has been proven to be anywhere close to accurate?

 

If I am putting out 360 hp, I have work to do. If I am 425 plus, I am probably getting about all I can out of this base setup.

 

Hey Grumpy, did you have a chance to play with my hp numbers based on my setup?

 

Thanks

Jeff

[grumpyvette]

Most, BUT NOT ALL, hp/e.t. calculators give you or USE, REAR WHEEL HP,

not dyno/flywheel hp, which is generally about 18% higher,some calculators give or use one and not the other.

IE if you’ve got 360 rear wheel hp that’s about 425 dyno or flywheel hp.

Your combo should produce closer to 450 plus flywheel hp with the tunnel ram, BUT Id suspect the restrictive exhaust might be holding you back.,keep in mind ,that, if your not getting good cylinder scavenging you can’t get full power)

Your combos a good basic hot rodders 383 and can certainly reach that 450 PLUS flywheel hp, with the right headers and exhaust and tuning.

DON,T get worried about HP, numbers,(their just numbers) just concentrate on the cars speed and E.T.(performance) and screw the theory and hp........most guys never have a MID 11 second car like youve already got!

and you can certainly get into the high ten second range with the right suspension,tires and exhaust, which is a very rare accomplishment for a street driven car.

don,t get crazy chasing numbers ENJOY the car,its far faster than most guys ever own NOW!

 

http://www.competitiondiesel.com/Phil/bg/

 

http://www.prosystemsracing.com/calculate.html

 

I’ve owned one VERY low 10 second vette, (10.25-10.27 @ 137mph several DOZEN runs)(BEFORE nitrous, and decent tires)it was impressive too own a car that fast, in the 1970s, but it was a major p.i.t.a. too drive it on the street, WITH ITS FULL ROLL CAGE, AND OTHER REQUIRED EQUIPMENT.

I had alot more fun with the cars that ran in the low elevens and even low 12 second cars, that required far less maintinance but were still much faster than average.

YOULL NEVER be the FASTEST guy at the TRACK on the budget most of us are forced to work from, so ENJOY what you can reasonably build on that budget, because youll make yourself crazy trying to always get a 1/4 second faster on a limited budget and without the time necessary to work on the car(most of us have jobs and families that are a higher prority)

[HICKL]

I am with you on all that and am very happy to have an 11.50 car that is very streetable and can be driven in any weather from 100 degrees to 35 degrees without any problems. Heck, I use it for a 30 minute drive in traffic every friday night to take my daughter to soccer practice, I was just getting bothered thinking that my motor was producing way less than its portential. The more calculations I do, I see that I am pretty close so am not worried about it.

 

Besides, if I ever get bored, will just hit it with a 200 shot of nos and see what happens!