We managed to take the car down to Sepang International F1 circuit for the drag battle event. WEhave previously retuned the car to 670 WHP/545WTQ and was anxious to see what the car could do on the strip.

The night was relatively cool with an ambient temperature of 85 deg. Just to give you an idea that this is only a made up drag strip without a VHT prepared launch area, thus getting off the line will be a real challenge.

Still with a set of proper timing lights, I took the car out on a first qualifying pass , launched the car at 5200 rpm, ( this is without a 2 step rev limiter and launching without boost) , nailed it , with the slicks screeching on forward, I gear changed it at too high of an rpm , and missed 2nd gear, still the car finished the line with a 11.83 pass.. not good at all, wasn't what I anticipated..

On the next qualifying pass, after checking the data logs, I decided that I should do a gear change as early as 7500-7700 rpm. Once again, with the tire pressures lowered this time, launching at almost 6000 rpm, I nailed it again this time with a better launch , less screeching on the slicks, I made an early change, 7700 rpm, took it to 2nd, 3rd, 4th, and finally 5th and clicked a 10.72 pass at 135 mph! Probably the best for the night..

The car was knocked out in the semifinals losing out to a stripped out AWD Mirage weighing prolly 600 pounds lighter,( ours still with full weight doors, interior, minus the seats of course) his 10.59 vs my 10.80...but still we know that there is more that we need to do to get the car into the low 10's...

THere's only one problem, there seems to be a significant disadvantage on the stroker motor as everytime I gear change into 3rd gear, the 2 litre cars overtakes me due to me not holding out the revs as compared to their 9500 rpm shifts, its only when I'm in my sweet spot after each gear change that I hold them till 5th gear at the traps.. ITs quite frustrating losing out by only a small margin...

We're planning to now run a 2 step rev limiter for more consistent launches and perhaps launch with boost for a harder launch, and probably run a 50 shot of nos to make over 700 WHP on the Dynojet...

But I reckon still the 2 or 2.1 litre is the go to run quicker on the drag strip....definitely prefer more rpm over a short revving stroker...

 

There is an AMS GT37 2.3 Evo that's doing 9.8 @ 147, so I'm not sure the Stroker is the problem. Then again, there are many experienced drag racerson here that may feel differently.

 

Blaming displacement for your problem is a little silly.

 

Blaming is not the word here but perhaps just weighing out the advantages vs disadvantages and of course having previously driven a 2 litre drag car vs a 2.3 litre, you gotta know where the difference is... I plan to still run a low 10 sec time with the stroker...

 

Yeah that guy from AMS did 9s@147 with 2.3L and 37R. You can do it!

 

That's some amazing power for a GT35R-powered Evo... congrats. The 2.0 high rev vs 2.3 low rev is a very good and valid point. I've still yet to hit 9,000rpm+ on my car out of fear... lol.

 

Based on the dyno numbers from your other thread, it seems revving beyond 7700 RPM isn't going to help much.

 

You've got that right... But the stroker at this power revs so quickly that its hard to catch it correctly all the time, will be looking at short shifting it next race to put it back in the sweet spot... The best time of the night was done with shifting around 7700 max and the worst being 11.0 shifting at almost 8100 rpms!!

 

agreed

 

why are you posting two different thread??

 

You could spin the 2.3 to 8.8k,so you could stay in 4tth gear.That what Dan Bajalis do.He do it for 2 race season and 0 failed.

 

You've got a point there. I will try doing that to hold to 4th then. Am planning to remove the main bearings to see if all is ok for going for that.

 

congrats on the times... I'm not sure what your gear ratio's are.. but depending on your rpm's I would hold it in 4th up to 8500. I'm just curious on why the slicks? I ran many low 10 second passes on all season tires with 1.6 60 foots. Just have to adjust your launch rpm/tire pressure and find the sweet spot.

 

The motor will hold fine to 8500 rpm's??If you take a look at the graph I have in the other thread, its actually dipping already. The slicks are needed as the track surface on the launc area is not good at all, almost like tarmac/concrete. All season tires spins easily. WOuld be happy if the surface was VHT prepared like a proper drag strip. THe gear ratios are similar amongst all five speed evos from the evo 4 up to the evo 7 I believe. Not much changes. are you running on launch control?

 

If you have enough power to use 5th and get 135mph traps, twisting the engine to stratospheric rpm (for a 2.3) may not be the key. As you mentioned, power is falling off rapidly beyond your present shift point.

Given your present power level with the GT35R, you're definitely on the downside of its efficiency range, and I may suggest considering a larger turbo. Along with that, I might consider a cam change, and I don't recall what intake manifold you are using . . .?

With a bit of calculated attention, you can increase the power a bit further by making the engine more efficient at high rpm, and get where you want to be without raising the shift points much further from where you already are.