Thread: Xp owners, input please?

What shift points are you guys running??
6200 or 6400 like zz p recommends??
Also are you guys running on stock crank pulley even with higher shift points?
Can our crank pulley handel 6400 shift points??
I'm running on 105lb springs with the xp cam.
And what kind of timing are you guys running??18,20-21??

The pullies are fine. My cutlass has an XP cam and 105lb springs and i shift around 6700-6800 with it. I have very agressively ported heads though and stock heads wont go near that high without falling on their face. I set most cars around 6300 shift points with the XP cam and it seems to be a good spot with stock heads, ported heads you can go a little higher and I wouldnt suggest the rpms I am running. The power starts to fade at about 6600 in my car. Make sure you are actually making the shift around 6300. You will likely need to have a lower shift point than that because stock or most rebuilt transmissions wont shift right when you command it to in the tune and there is often a 100-300 rpm lag on the shift so it will take some testing to get it where you want. The top of 2nd gear will tell you if you are revving too high as you will feel the power nose off if your shifts are too high. Dont be as concerned with the engine not wanting those kind of rpms because it will handle it just fine, focus on how the power curve feels.

All right thanx.
Right now i have the shift points set at 6200.
What you think?
I made a pass this friday and only trapped 100mph.
I just found out i was runing on 17* only.
Would th ex-tra timing get my trap higher?
They tell me i should be traping at least 105mph.

Bump!

How well the car runs at the track has a LOT to do with the tune. A local guy had a top-swap car and after I tuned it with a wideband he went back to the track and picked up about half a second and 4-5 mph IIRC and this was on the same exact setup and poor 60' because of the street tires on the car. You could try bumping up the shifts to 6300 but it isnt going to give you 5 mph from bumping up your shifts another 100-200 rpm. Fuel and timing are the key elements. What pulley were you running for your track passes? Did you have any KR and what were your 02s at? Narrowband 02 #s seem to be useless often but I have found a few common numbers that seem consistant amongst different 02 sensors. If the car is running too rich it will really kill your top end.

I was runing on the 3.2 with stock timing with no KR.
i bumped timing to 17* and only had blips of Kr after the shifts.
As for my 02's i think i was at 940.
thanx for the info!

Yeah location-elevation, temp, humidity have a great deal to do with how the car runs and what you can sqeeze out of it. Your 02 numbers depend on what sensors you are using. I have found that most aftermarket replacement sensors read on the high side at WOT but OE or aftermarket arent the best thing to rely on for full throttle tuning and a wideband is the only accurate way to see what you have. I have found over the last few years of wideband tuning that typically stock GM 02 sensors until the 04-05 year range will read in the 885-905 range at 11.5:1 AFR and some aftermarket sensors will read in the 940-965 range at 11.5:1 AFR. What really adds to this is that during a quarter mile pull the stock narrowband numbers will drop even if the wideband is reading the same number the whole run. 920s was pretty much the rule of thumb to go by as a target number before guys started using widebands for tuning, so 940 could be a little on the rich side.

Yep I use the NGK-AFX. It is not the prettiest thing in the world but I bought it because a few guys on the HPT boards highly recommended it and one of them does OE computer tuning for GM iirc and said the NGK sensor was one of the most accurate. I also bought it because it is more of a portable type gauge than the 2 1/16 gauges and this is what I use when I tune cars. I have had this one for about a year and a half and has never given me a bit of problem and has a great price tag.

Originally Posted by TDCRacing

920's sound more like where you want to be at. Then again what is the ambient temp where your at?

We usally have 100* weather almost year round in south texas.
That day, it was high of 96* and low at night of 80*.
We run at night at the track.
But it was reall hudmid that day.
79% of humidity to be exact.

Without an intercooler on these cars you are really hard pushed to make good power in high temps and humidity such as your conditions and really limits your tune capabilites to accomodate for the weather.

Originally Posted by Trannyman95

Without an intercooler on these cars you are really hard pushed to make good power in high temps and humidity such as your conditions and really limits your tune capabilites to accomodate for the weather.

No kidding.
The local member doing the tune, has had a hard time since day 1 tuning my car.
Ic is on the future mods list already.
But its taking some time to put the cash toghether.

Yeah, i'm going stage II Ic from zz p.
No need to go with ss Ic and then thinking i should of gone stage II.
Do it, do it the right way.