Sitting on the dyno

[Roger Reid]

Well, the "Hammer" had some low speed idle hunting issues. So I took it to "Throttle Works" in Boise. They have some knowledgeable people there who know the E-38 ecu pretty well. My goal was and is drivability. They use a Mustang dyno which usually reads lower numbers than, for example, a Dyno Jet. No numbers yet as I will enplane below.

I don't have final numbers yet as there are some issues. The engine is an LS7 from Schwartz. What I found was...

First, the fuel air ratios near idle were up and down near idle. That caused the "hunting and surging" I was experiencing. That has been corrected and now drives well.

Second, while under full load we had some knock. So he backed off the timing from 29 to 27. Still had some knock so he went to the knock tables and found they were zeroed out. Translation, no knock control. Perhaps Schwartz designed this tune as a race engine only which could justify zeroes in the tables. Now there is a question "are there any knock sensors below the manifold"? Now I get to take the manifold off to find out.

So if there are any other Schwartz LS7's out there, check your ECU tunes.

There a few more "to do" items before bringing it back for another dyno run. I'll post numbers when I get them.

[Cattrax]

I would advise anyone not to hesitate to have an independent check if they have anything but a factory ECM and tune. Mine was supposedly tuned by a reputable shop. They had the high and low octane tables switched! Also the wrong MAP sensor and several other anomalies. It ran, but not right. The checking was done with EFI Live which I believe has the E-38 pretty well sorted out. I question if some of the other tuning software has bugs in it but that is just a guess.
Ken

[VRaptor SpeedWorks, LLC]

I know on other LS engines, the knock sensors are external and mounted about right in the center of the block on both sides....right behind the aluminum engine mount brackets. So the LS7 has them located internally?

[Roger Reid]

Shane, I think you are right. I will put her on the lift and check just to make sure the knock sensors are on the sides.

[Kempo]

You have one nice looking GTM!!!! The older LS engines LS1 and LS6 have their Knock sensors under the intake manifold. LS7s have them on the sides of the block.

[The Stig]

Kempo.

It's good to see that you're still here from time to time!

Mike

[Roger Reid]

You have one nice looking GTM!!!! The older LS engines LS1 and LS6 have their Knock sensors under the intake manifold. LS7s have them on the sides of the block.

I put her back on the lift. Yup, the knock sensors are on the side of the block. Now I just need to find a copy of the ECM knock sensor tables for an LS7.

[Kempo]

Kempo.

It's good to see that you're still here from time to time!

Mike

Hey Mike, I do drop by from time to time to see how the builds are going. Glad to see yours is coming along nicely.

[Roger Reid]

One of my to do list before putting her back on the dyno was to wrap the exhaust under the air intake. The headers were wrapped before the engine installation. It seems that while sitting still either on the dyno or at a stoplight, the air intake temperatures were spiking because of the close proximity to the exhaust.

[Fraser D]

One of my to do list before putting her back on the dyno was to wrap the exhaust under the air intake. The headers were wrapped before the engine installation. It seems that while sitting still either on the dyno or at a stoplight, the air intake temperatures were spiking because of the close proximity to the exhaust.

You may want to consider making a shield and potentially coating that shield.
I made some up and sent them of to jethot to help manage heat.