Hello everyone,

I am in the process of prepping my car for the NHRA event at sacramento raceway on august 11-12. One of my concerns is regarding headers....which i have 2 questions...

1. At this time i am running a JDM 4-1 and I ran my car open header the last time i took it to the track. I noticed there was a great deal of lag on the lower end, the vtec transition point seemed to stall, but the top end pulled strong. And i know some of you advise against this due to not having any back pressure at all..

At this time is there anything i could do to possibly solve some of my problems? I know tuning a header has to deal with adjusting primaries, but if i installed a straight pipe to the collector would this help any??? and i would still have the entie exhaust system disconnected with just an added 2ft-3ft at the end...

2. Weight is a main concern and i am going to leave my exhaust system at home. However, the track is roughly 70 miles away. I would not beable to make it to the track running open header due to the noise level. Would that added pipe ease the noise level and what else could i do to even lower the noise??

THanks for taking the time to read my post. Any suggestions would be greatly appreciated

Eric

 

I just want to say I'm not a proponent of the statement "And i know some of you advise against this due to not having any back pressure at all".

The reason you want to run a tail pipe is because the flow through the tail pipe helps evacuate the header. If you run the header open, it just dumps to the atomosphere and the energy of the exhaust flow is lost. I posted something about all this under a thread a few days ago. A header with a tailpipe tuned properly should always be the best set up, but if the collector or tailpipe is too large it can almost be like running the header without a tail pipe.

There are some general rules about picking the proper length for the tail pipe. One is using some real cheap paint and cutting the tail pipe where the paint stops burning up, another one is to use a length roughly equal to the tube length of the header and for the JDM that is 30"-31". But the best rule is to use the length that gets you the best results and the only way you'll know is to test. You can start with a 12" piece and bring a bunch of 6" extensions to the dyno or track, run - add length, run - add length and keep adjusting. If you are serious you will start making changes in 2-3" length increments once you find what works best in multiples of 6".

As for the noise, just run the exhaust to the track and then take it off. It doesn't take long, plus it will give that guy who bummed a ride off of you something to do.

Hope this helps.

 

Hrmmm is this part of the reason or THE reason the DC Ti Race header puts out so much punch at the expense of noise etc??