Boost/Tune question

First my last engine (Ford replacement) would (by my memory) peg the boost gauge easily, now I don't climb above 10PSI till over 4000RPM, is this normal? No overdrive, and new Gates belts.

Second and this is down the road, the only SCT dealer in my area wants $400 for dyno time is this normal (they have never done a SC)? Could someone suggest someone in the greater Memphis area? QH seems like a possiblity but I don't plan on changing things once get Heads/Cam.

Basically I want to be 12.8-13.2 in the 1/4.

Also, my Narrow band O2 is showing at best one to two tick on lean but most of time Stoch side of lean to Full Rich.

if your tapped into the narrowband to feed a stupid lean/rich gauge then your actually making the car run richer because the gauge steals just a hint of power from the o2 sensor

thats normal behavior your witnessing though

best bet would be to get a QH and let one of the many resident expert tuners here get you situated

SCT has minimal support for the early supercoupes, they don't even give you access to the backflow clip function or the inferred load table

where are u located?

bowez said:

First my last engine (Ford replacement) would (by my memory) peg the boost gauge easily, now I don't climb above 10PSI till over 4000RPM, is this normal? No overdrive, and new Gates belts.

Second and this is down the road, the only SCT dealer in my area wants $400 for dyno time is this normal (they have never done a SC)? Could someone suggest someone in the greater Memphis area? QH seems like a possiblity but I don't plan on changing things once get Heads/Cam.

Basically I want to be 12.8-13.2 in the 1/4.

Also, my Narrow band O2 is showing at best one to two tick on lean but most of time Stoch side of lean to Full Rich.

Click to expand...

The QH is the only way to go with these cars... there's nothing out there that can come close. You may say that once you've done the heads and cam that thats it..... but remember who you are talking to on here.... most people have said that several times .

For a bit more than that dyno tune you can get all the gear and software you need, then learn to tune it yourself by using the tuning forum here (I'll be blunt, don't waste your time with other sites... they don't know how to tune SC's, and some of the things they do to tune are very questionable). The main tuning guru here, Dave Dalke (XR7Dave) can get you setup with everything.

Fraser

I'm in NE Arkansas. 72401

The reason I ask about the A/F is I don't remember it being so rich (showing anyway). Now it has been about 2years since I got any real driving time on it, between the engine swap/rebuild and tranny swap. Curious if the rich A/F and lower boost might be related. I would have thought that the motor would actually produce higher boost, the previous pistons were way over; no measurements but the shop said they were defiantly bigger than .030 over.

Fraser I know you and Dave a the go to guys and all, though originally I didn't want to drive the car to Ohio and no offense I anit going to Canada. Though since I have taught myself BASIC and CAD how hard can QH be especially with help.

I'm sure the tune Jerry put on there was a safe tune I'm just a little let down with my times not being where I thought they would be. Tune is probably 8yrs old.

bowez said:

I'm in NE Arkansas. 72401

The reason I ask about the A/F is I don't remember it being so rich (showing anyway). Now it has been about 2years since I got any real driving time on it, between the engine swap/rebuild and tranny swap. Curious if the rich A/F and lower boost might be related. I would have thought that the motor would actually produce higher boost, the previous pistons were way over; no measurements but the shop said they were defiantly bigger than .030 over.

Fraser I know you and Dave a the go to guys and all, though originally I didn't want to drive the car to Ohio and no offense I anit going to Canada. Though since I have taught myself BASIC and CAD how hard can QH be especially with help.

I'm sure the tune Jerry put on there was a safe tune I'm just a little let down with my times not being where I thought they would be. Tune is probably 8yrs old.

Click to expand...

Time for a new tune... even a base tune from myself or Dave can be a huge improvement over an 8 year old tune.

As for the narrow band. The only time that gauge is of any use to you is when you are idling or cruising along, any other time its useless and should be pegged rich in boost. That gauge will only show AFR between about 13.8 to 15.2 or so, if that. When your going into boost the computer is already commanding into the 12's and by the time you get close to WOT about 11.7 or a bit richer. If your AFR gets into the mid 12's at WOT your inviting trouble.

As for the boost problem, that is a mechanical problem. You need to check that you don't have boost leaks (not vacuum leaks), and that the bypass valve is operating properly. I've seen a lot of cases where the bypass valve looks closed, but it hasn't closed far enough to completely seal up, and it doesn't take much of a leak there to lose a lot of boost.

Fraser

I'll look for boost leaks, if memory serves I had issues with the by pass hose.

Before I retune I'll have to get the 5.0 back on the road.