So I took the car to the track today, a week after my tune and dyno.

My two better runs were 14.20 @ 99.2 (2.2 60') & 14.27 @ 99.9 (2.35 60')

Considering the fact that I've added rims, tires, shocks, intake, plenums, mounts a neo and had it tuned and only ran 0.15 better, I m really disappointed. I also trapped almost three mph lower then before, which just blows my mind.

I trapped at 101 or 102 last time with a 14.35.

I am sure that if someone was a better driver they could do a little better then me, but how are people running mi-13s ?!

 

Are your new rims and tires a larger overall diameter? Also were weather conditions worse this time? The guys in the mid 13's have a SC. I think a 14.2 is good, and your mph was lower because your 60" was lower. The 13's are hard to hit if you ask me.

 

I will tell you right now that your little RT CAT is your problem. The cat is like 2 inchs and the rest of your exhaust is 2.5. You have all of those mods to pull in air but you dont have the right air to get the air out. Thats your problem. Last summer my car was running 14.1s @99 with only intake, header and crank pulley. STOCK EVERYTHING ELSE. And especially since ur MPH is lower than it was with less miles, thats clearly a loss in top end flow. 102 MPHs with what u have now should easily be pulling u 13.7s

 

18's are kind of big for your setup. Very nice for the street, but in terms of trying to get a fast 1/4 time, i recommend you run a smaller rim on the track. This will help improve your 60 foot time.

Also I can assure you that the RT cat is hurting your top end, as it really is to small of a diameter in and out, which is good for low end TQ, but not great for high RPM, and at the track you are in high RPM the whole time after your 60 foot. Change it to 2.5 in and out, and I can guarantee you that your HP will be higher in vtec.

Another note, make sure that your flex pipe on the XS header is not leaking, as I know those always leak. I normally like to just cut out the flex that came on them and replace it with another flex pipe. If you listen to any of this advice, let me know how it works out for you. I am sure you will be happy.

 

true story

 

My tires are one size up (225/45ZR18) then what I needed, but they were 50% off at tirerack a while back. If I recall correctly the circumference is 2% larger then stock.

Power Rev,
Do you recommend going even smaller then the stock diameter? I imagine eventually I ll wont be able to get any traction, whats the sweet spot in terms of wheel diameter?

.

Are there other options then the RT Cat? I only bought it b/c I broke my regular Cat (long story) You guys don't make a 2.5" pipe spool piece to get rid of the cat, do you?

What brand flex pipe do you use? I guess I could get another set of headers and have a shop redo the flex pipe.

 

Also, when do you guys shift? I did at redline at every gear, but with the huge drop off in tq at 6K, that may not be my best option.

http://docs.google.com/Doc?id=ddzzrccs_31q7vc6vpx

Is the goal to have the highest avg hp through the gear, or the highest avg tq, or some combination of the two?

 

Just came back from the track today -- 10 C (50 F) weather in Toronto.




The image may be a bit blurry but I ran 14.185 and a few other 14.1s

 

I have a RT cat me too.. how do you change the diameter? It is possible to take it to a exhaust shop and cut it and put a 2 1/2 diameter piping instead and weld it?

 

damn, seems like a lot of $$$ in mods to get you kinda no where at the same speed...lol..

 

well true that,,,,,,,.......

 

Yeh...Thanks

 

I have the Magnaflow High Flow Cat, I wonder if it runs into the same issues as the RT Cat:

http://www.hottexhaust.com/detail.asp?PRODUCT_ID=27403

From what I have found they say inlet and outlet are OE size. This might be a good replacement for you.

 

Not really, everyones cars run different and when your NA you have to keep in mind that all the mods have to work together and that one small issue like too much exhuast restriction can slow down all your potential. I mean going FI is on average adding a extra 60whp so all the back pressure in the world wouldnt stop a car for providing better results than it did NA even if its a little bit.

 

SkillOBskilled

What track did you run at? Your problem has to be traction or a slipping clutch. or the wheels are killing you. I would say traction or wheels since you didnt have the problem on the dyno.

I ran at atco last year completely stock and got a 14.42@96.76. and I know you have the HP and TQ to destroy that.

CLS6speed......I am impressed with his numbers even with the RT cat. Don't you think it would have shown up there if it was hurting him. I mean it could be hurting him but i dont think it should be hurting his qtr mile times.

 

i ran 14.34 (!)completely stock i mean only tint and skunk2 knob is a mod right know tomorrow imma put new spark plugs 215/50/17 tires everything else stock imma try hit 13 with some mods. we'll see

 

I went to Atco. I ran 15.2 stock, granted that was a month after I learned how to drive manual.

A few people thought that RT cat is hurting me. Vince at R/T tuning said the same thing when I asked him where he saw room for improvement.

I ll will try to work the kinks out next season. Winter tires are going on soon.

 

run a test pipe instead and see the difference

 

The tires are hurting your gearing. That's the main problem. Your trapping high MPH & your 60's are reasonable. The car is sapping power at low rpm trying to turn those tires, The mods you have are making up for it on the top end hence your high trap MPH. By then it's to late though. You should be at least 13.9 with your 60 foot's.
If you ran 235-40 18 or 235-45-17, or even stock 215-50-17 you will see the times shrink.

 

Hey Dru, what track do you go to? I'd love to go sometime in the spring.

 

I went to Cayuga on an early Sat. morning - didn't have to wait in line for any of the races.

 

Skill are there certian req. you have to meet to use the track?

 

A lot of good advice so far. Did you finish your car with tuning, was it after the RT cat was put on? Looking at your dyno, I can see you share the top end curve of a J32 with a choking exhaust. Did you run the RT cat before when you hit 101/102 traps? I managed to also hit a 102.3 with my RT cat or possibly my stock J30A1 cat, can't remember which it was at the time but the J30A1 cat is more restrictive.

Plus.... + have to toss this out there... make sure your IMRC plates are opening up.