JGT

I've currently got a Brenspeed 93 Octane tune and will be installing longtube headers in a few days. After the install, I am going to have them throw the car on the dyno. I am perfectly happy with the Brenspeed tune so far, but I want to make sure the tune is safe and that I am taking advantage of the longtubes. I talked to Brenspeed and they said they can look at the dyno results and adjust the tune for me over the phone.

My question is...Am I better off just having the car tuned while it is there on the dyno? Any disadvantages to just having it tweaked over the phone (aside from saving a little cash)?

Also, if I choose to just modify the tune through Brenspeed, will it be OK to drive the car around for a few days without tuning itfor the longtubes? Could I be running lean without a new tune?

Stang Skeleton

You probably dont want to drive around with out a tune specifically for the long tubes, the A/F ratios etc will be way off and you can damage you engine in the long run. Depending on how good the dyno shop is, they will probably be able to make the best results by tuning the car in shop while being able to play around with all the variables with the vehicle present. Its also good to have it tuned at the shop in case any unsuspected problems occur.

acascianelli

+1

Have them tune it, if they are any good it should be just as good if not better than any mail order tune.

drbobvs

I will disagree on this, to a point. These S197's are a very different animal and not just anyone can tune them properly. Brent is superb at what he does, probably one of the best in the country for N/A engines. Unless the shop doing the install is extremely experienced and familiar with these cars i would not have them dyno tune it. Since the tune supplied by Brenspeed is not accessible to the dyno shop they will have to build a tune from the ground up. Not only will this cost some $$$ and time, but don't be suprised if your final result nets you LESS hp than before the headers. Also don't be suprised if your car doesn't, feel the same, esp if it's an auto.

JGT

I have been leaning towards getting it tuned at the shop, but this is the one argument that has me questioning this choice. But the shop is a pretty reputable shop, they work on quite a few Mustangs and all work I have seen seems to be good. This isn't just some random shop with a dyno sitting in the corner. They are an SCT authorized dealer with ASE certified, dealer trained mechanics, does this mean I can trust them more?

Of course, I have waited untilthe last minute, may have the headers installed by Saturday, and so if I do go the Brenspeed route, I will have a car with longtubes and won't be able to safely drive it for five days until I get the new tune from Brenspeed (they say 5 days is the standard lead time).

drbobvs

You'll certainly be able to drive it! You may not want to go WOT too many times or take to redline at WOT, but a DD you WILL have. Your A/F tables will only be off, if they are off at all, significantly at WOT.

JGT

I just called Brenspeed and they told me that typically adding longtubes does not require a re-tune, and that any re-tuning they do is either to turn off the 02 sensors or to adjust the 02 "transport delay"to prevent CELs dueto the sensors not warming up as fast. He really didn't think I would have a problem with running lean or anything. My longtubes are catted, by the way. This may not apply for non-catted setups. He also said they have not had much of a problem with the American Racing Headers throwing codes, but have had a difficult time getting the codes to go away with the JBAs.

I am going to have the car dyno'd anyway to make sure it is safe, and if I have any problems with CELs or it looks like the tune could use some modification, then I'll get a re-tune from Brenspeed (only $35 since I purchased the tuner from them).

Sherwood06GT

+1

I just had (30 minutes ago) a Dyno run and the A/F ratio is spot on. There was no deviation from normal with the long tubes installed.

JGT

When the car is on the dyno, they monitor the A/F ratio and can shut it down if anything goes awry, right? This will be my first dyno run, it is going to be a hot and humid day and I am getting paranoid about redlining the car on the rollers.

Sherwood06GT

Yes, that is true. Also, bear in mind that on a hot, humid day you won't get the best dyno results. The best time is a relatively cool day, with lower humidity.