RenaissanceMan

Dual carbs... What kind of power yields?

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Was curious if any of you running a twin sidedraft setup have ever had your cars dyno'ed? Without messing with any internals, will a 2 carb '02 equal or surpass stock tii performance and/or horsepower?

Edited by RenaissanceMan

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With everything else on the engine being stock you'll wind up a bit short of Tii h/p, but with the sidedrafts you could modify the engine C/R and cam much easier than a Tii

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RenaissanceMan...having both a tii and single carb car the way the horsepower is delivered is much different between the two ...my single carb car seems much quicker/more torque er in everyday driving...if you are racing I have no idea of how it all works out...what's your end goal?

43 minutes ago, RenaissanceMan said:

will a 2 carb '02 equal or surpass stock tii performance and/or horsepower?

 

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When i had my '72 2002, a buddy bought a '72 tii. This was early 1990's and both cars were in good running condition. My car had a 40dfav downdraft carb and a stahl header, his tii was bone stock. We hammered the local roads and did countless acceleration runs, both cars ran neck and neck. 

 

Same trans, same rear gear the cars were exactly the same speed.  Driving the tii was a different experience with smoother throttle response and a general feeling of refinement.  

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Nope, dual carbs won't equal a tii, on a stock carbed engine.  On a tii (higher compression) engine, they might- at certain revs, at a certain barometric pressure and air temperature.

 

As my Southern neighbor (it kills me that North Bend is South of Here) says, it DOES open the door wide to mods, from cam to exhaust to compression.

 

And dual sidedrafts are not HARD to tune, yet many are not optimally tuned....  a 38/38 is theoretically more carb than 45 DCOEs...

 

t

 

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Short answer: The tii winds up better and likely gets much better gas mileage. The 2002 with dual sidedrafts has better throttle response and sounds better. As you pair the dual sidedrafts with high compression pistons and a cam, the actual performance improvements should increase substantially. 

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2 hours ago, Son of Marty said:

With everything else on the engine being stock you'll wind up a bit short of Tii h/p, but with the sidedrafts you could modify the engine C/R and cam much easier than a Tii

 

This is great feedback, everyone, thanks! I've owned a '74 tii and a '72 tii. My current '76 02 is my 3rd non-tii. (Yes, I can't seem to shake these damn cars.) To be honest, its low end and midrange performance doesn't feel drastically different from the tii's I had. Probably a function of various states of tune between all of my past cars... My current car is completely stock except for the single downdraft Weber on it. Because the car is so original, I don't have plans to do anything drastic to the car like an m20 swap, etc, but I would like to maybe do some period-correct aesthetic mods (chrome bumpers, wheels) as well as some basic suspension improvements and maybe add a little more grunt. I absolutely love the sound of twin sidedrafts and was curious how much more this mod would improve the 'butt dyno' numbers. Any other feedback y'all can offer as I contemplate my project list for this year is greatly appreciated. :)

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Edited by RenaissanceMan

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I just installed dual 40 DCOE's on my '71 2002. Basically stock motor with shorty header and stock muffler. The throttle response is noticeable and I feel like she pulls better at higher RPMS. I really need to up the compression ratio and install a 292 cam. But the next sound and the look, so sweet!


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I just installed dual 40 DCOE's on my '71 2002. Basically stock motor with shorty header and stock muffler. The throttle response is noticeable and I feel like she pulls better at higher RPMS. I really need to up the compression ratio and install a 292 cam. But the next sound and the look, so sweet!


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What carb "kit" did you end up going with? Did you buy a complete 40DCOE package or piece together yourself?

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I bought the kit (K-206) from Redline and pieced it together, fuel pump, filters, etc..


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Most guys I know that have the dual carbs have basically rebuilt the engine - higher compression pistons, 292 cam and some sort of header.  

 

If you are just doing the bolt on approach, one thing that might help would be some sort of exhaust header along with the carbs.  You would be getting the full "sound experience" then, and maybe it would breathe a little better for somewhat higher performance.  

 

Your car looks great, by the way.  Have fun with it.  

 

Scott

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Don't forget ignition, that's a must to upgrade when using side drafts , my 45's run brilliant & the Computronix ignition I run is amazing from idle to red line , smooth as silk.

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33 minutes ago, LimeySteve said:

Don't forget ignition

Absolutely.  Most of us are running 40 year old distributors.  Shim and shaft wear, bad grounds, weakened springs and even broken housings all contribute to make proper tuning nigh impossible.  But dizzys are usually the last thing anybody thinks to replace.

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