MPG seems a bit low. Mine usually ranges in the 12-15 area. Might take some more miles though as things get settled.

 

Has anyone run headers with this swap? I'm assuming if the factory gm exhaust manifolds are used so it would reason that headers for something like the vehicle the engine came out of might also fit.

My real question is around long tube headers because I don't know that I'd go to shorties over manifolds. I'm going to guess nobody has tried to fit long tubes with a gm v8. Or at least nobody in this discussion. If someone had fit shorties then maybe that would lead me down the path to enlightenment on finding a shiny set of stainless long tubes.

Hope for the hopeful. I have a welder haha.

 

I don't believe anyone has headers going but I have thought about it myself. You'd have to get them custom made, and if there would be any real performance gains. This things not a sports car keep in mind, and I would be concerned about the transmission if we up the HP.

factory manifolds can't be used because of how narrow the rover frame rails are. The kit specifies the use of a specific manifold that has been tested to fit. It is quite narrow. Its the bottom portion that's the issue, the part that connects to the actual exhaust. There's probably less than an inch of room between the frame and the manifold.

I'm sure there's other things out there that will fit, but as you already know nobody has tried yet.....

 

Upping the horsepower might give you cause for concern, but my lm7 will need some work to reach the l33 hp anyway.

On the transmission subject... Upgraded converter, shift kit, etc. What options are there besides sending the trans to jolly old England for a build? Obviously a bigger cooler is wise.

I'm totally planning to keep an eye out for a spare trans just in case because something like a BTR truck cam is calling my name and with a tune that's asking for maybe 350hp on the optimistic end. As with most my life I'm assuming I can figure out what I'm unwilling to afford haha. I'm either very cheap or mildly handy.

 

Easiest upgrade is a larger cooler. I am running two in parallel - the factory cooler and a big Derale cooler. It made a noticeable improvement in shift quality to me.

They did make a larger converter that was used in the 96-98 P38s. I don’t think it will fit the ACE kit though. A big cam will be a problem for the stock converter. I would limit to a relatively stock cam with a normal idle that does not need a converter.

As for a shift kit, the best option would be going to the Compushift, which lets you control all the shift parameters. The factory trans tune works fine for a stock 4.8/5.3, but it can be improved for a performance-oriented engine. I have seen some valve body mods done on the Audi forums as well, but that requires taking the valve body apart. I also made the circuit board mod, but that just changes shift points, not pressure/timing.

I think the 4HP24 can be stronger than people think as long as you don’t abuse it. The 4HP22, especially the manual valve body version found in the D1, RRC, etc., was not as strong. However, the 4HP24 had a number of substantial improvements over the 4HP22. The electronic valve body control that came in the D2 also helps substantially. I think that with a proper setup, the 4HP24 could handle a 6.0. They’ve handled a lot more power in other applications (BMW 750/850 V12 plus twin turbo and supercharger kits, Overfinch small block Chevy P38 conversions). That would require the right setup, meaning big cooling, a Compushift or tuned factory ECU for precise, firmer shifting, maybe a different converter. I have heard of one person running the ACE kit with a 5.7 LS1 and another with a 6.0. I’m considering another build with a 6.0 / 4HP24 combo. I want to do some more research though.

 

That's all good and reasonable input. I agree that keeping it cool seems like the first and possibly most important step. a big cooler or a 2nd cooler would be in the plans at a minimum.
I wasn't planning a cam that would lose much if any bottom end. The BTR truck cams don't seem to shift the max hp or torque up much in the revs. The test I saw that Richard Holdener did showed a max hp at around 5500. Seems like a no brainer for a little extra power. That cam with 4.8 flat top pistons might make for good gains from idle to redline. Albeit at the expense of maybe running higher octane. https://www.motortrend.com/how-to/19...muscle-counts/

I like your electronic box for altering the shifts. I need to sit down and really think it out. I think I know what you're doing with it. I still need to have my aha moment though.

 

I've been getting a repeat engine code pop up, anybody else had this one?
P0507 - idle Control System RPM - Higher than Expected

need to do some more looking around of what's happening....everything is working just fine...I noticed this morning it came back while I was coasting, no gas...RPM was somewhere between 5-1K...

Reading online a lot of talk about cables running from the alternator..;
- I've got a positive lead connected to the back end, negative lead connected to the bottom bolt hole, and then a lead going from the back into the ECM.
Does it look like I've got my cables in the right spots?




I've also read things about MAF and intake...I know some have had to cut the baffling from the intake box for better airflow...could this be something?

 

Check to make sure your GM ECM is getting a good speed signal by reading the vehicle speed on the GM OBD2 port. That can cause this code.

 

Hey @CaptainAaron It doesn't look like the GM ECM is seeing any signal at all.
I had my BlueDriver running for about 5min and got no reading at all. At one point it randomly jumped to 280km/h though...but I had it in park...

What does this mean then...where do I go from here?

 

I don't know how the BlueDriver gets it data, so that could be contributing. I'd first check that you have the VSS wiring with the ACE box right. The fact that it randomly jumped to a really high value implies to me that the connection is not great or BlueDriver is getting data from a random place.