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-   -   1/4th mile timings. Opinions needed. (https://www.team-bhp.com/forum/technical-stuff/28977-1-4th-mile-timings-opinions-needed.html)

Hi guys,
Just needed your opinions for 1/4th mile timings. At the FEB Speedrun, my Corsa 1.4 did 18 sec with K&N conical filter, Automech 4x2x1 free flow exhaust, FSE fuel pressure regulator and Iridium plugs.

Now, in addition to those, the car's got ported and polished head, ported and polished intakes, enlarged and polished throttle body and 270* Piper High lift cam. Plus, before the drag, it'll have a race dynamics standalone performance ECU, maybe bigger injectors, stage 2 high comp pistons and custom performance headers from Raj from Bangalore with a short pipe.

Just wanted to know, what do you guys think should be the 1/4th mile timings after all these additions. Start shooting guys.

im not really sure but the gearing might prevent you from getting drastically quicker times.
probably the drag gurus could help you.

why dont find an empty stretch - do some runs - and keep a log as you keep on upgrading the engine :)

We're working on that too.

Put it on Dyno & see how much power she is putting to the wheels after all the mods you listed.

I'll surely do that Rocam, once the ECU and pistons are in place. Right now I'm just looking for some assumptions and some healthy arguments.lol:

search for time slips for similarly modded cars abroad.

Try G-tech pro or similar timing equipment, it wont be 100% accurate but you will get an idea.

wild guess, should shave another 2-3 secs.

Too wild "jaggu dada".... Not to dampen your spirit "Adman" but Honestly dont expect that much.The timing depends a lot by the torque produced by the engine at particular powerband, in other words you should stay in that powerband where your engine is producing maximum torque.

to give you an example we were testing timing on Bhushans (EVO6) Audi TT with 250 bhp & 6500+ rpm redline. we were constantly getting timing of 14.7xx-15.xx in every run. not impressive for 250bhp TT, we found that we were shifting every gear at around 6000-6500rpm. only in 1 particular run she timed 13.6xx when he was shifting a bit early.
Next day while analyzing his dyno graph we found that the engine produced peak torque at around 5000 rpm & after 5500 rpm the torque dropped drastically. He had shifted every gear in 5500 rpm range where max torque was produced & that was the reason timing came down to 13.6xx
so staying in powerband is more important with list of mods. thats the reason i asked you for dyno graph.

13.6?? You sure, Rocam sir? That's WAY optimistic for a 250 BHP FWD TT...

Mid 14's is sound more realistic...

Just a pointer, though; I've noticed that not all cars react the same to the torque graph. Technically, the Swift puts out 113 NM at 4500 RPM, but I found max thrust to peak at 5800-6000 for optimal upshifts; although the peak power of 87 horses is claimed at 6000, & redline at 6600. Same in case of the Corolla; I have noticed that even though the peak torque of 158 NM kicks in at 4200, max thrust kicks uptil 6K...even though the redline's at 6.5K, and max power peaks at 6K...

Perhaps the Japs are more revv-happy & prefer shifts up the rev-range, whereas Germans & Euros prefer to ride the torque band?

@adman; with the mods that you've listed, you could shave off half to a second tops; if lucky...

That was tested on Gtech Pro, so pls dont consider it to be 100% accurate, but for testing it served the purpose.

@ Veyron i posted what i observed its not that i heard from somebody and relied on Butt dyno. & with 250bhp high 13" should be acheivable. as far as this TT is concerned i think its @wheels not sure though, EVO6 can confirm on that.

I am trying to say how a proper driving technique & proper gear shifts can contribute to good timings. Its not power always, how its delivered to ground is what important.

hey veryon1 i guess the reason for your findings is the drop in rpm! it would be interesting to try it out though!

@ford rocam:just for academic reasons,if my zen produces peak power at 6000rpm and peak torque at 3500 rpm,at what rpm should i be shifting gears to get the fastest time.an approx guess would do or is there a formula or logic to calculate this.

Generally they say that an engine is most efficient from max torque rpm to max power rpm (since max power is achieved when the combination of engine speed and torque is at it's strongest point). So, redlining every gear maynot be a wise option especially if max power rpm and redline rpm are spaced far apart.

But you also need to see how the gear ratios have been set. If shifting at max power rpm slots the next gear lower than the max torque rpm (below the power band), performance in that gear is bound to drop till you hit max torque rpm.

So unless you get a complete torque and power curve chart for you car's engine, you can only hope for positive results.

Shan2nu