View Full Version : Back from Dyno 224hp 327tq 3.2lbs of boost

12-06-2013, 12:55 PM
Just got back from the Dyno. I just did 2 pulls. The first pull a coupling blew off. The 2nd was stopped early do to a lean condition.

Have a problem with the SC. It isn't making any boost. Looks like I have a by pass valve that is fauly. I had the car on a smoker and there aren't any leaks. The moaning that you can hear in the video from what I understand is the by pass isn't working right.

Arthur was great. Welded in a sensor to get a accurate afr. He hooked to the boost vacuum and the fuel rail to get accurate fuel pressure and boost.

What do you think from the info?

Mike Puckett
12-06-2013, 01:38 PM
Check the vacuum hose on the actuator. If the actuator is bad I've got a couple of extras.

12-06-2013, 01:47 PM
Pm sent Mike
See you soon!

12-06-2013, 01:48 PM
Well up side is only 3psi explains why it felt like a dog, and 225hp at 3psi ain't too bad. Wait til you get it right :D Did you come up with a reason for the lean cond? The fuel press map looked like it was falling off during the pull (about a pound) not much, but I would have thought you would have wanted to see it steady, or even rise with boost/RPM. What fuel pump is in it, and can it keep up?


12-06-2013, 02:12 PM
Adam those are good questions and I really don't know. Some thoughts are that with the blower not working properly it is effecting the maf and that is messing with the computer and that is messing with the fuel but that is a guess and probably not a good one.
Smarter people than myself will let me know.
The good news is that when it is mechanically healthy and the tune might need a tweet it will be a healthy SC.

Wondering about fuel pump too. Has 58lbs injectors so that isn't a problem. Maybe the fuel pump is tired?

XR7 Dave
12-06-2013, 04:40 PM
You have a number of mechanical issues. The noise that everyone is guessing at is caused by your FMIC and the large, loose fitting silicone connectors. Noise is emanating from the large gaps between tubes.

The lifters are making noise. I sent your pushrods today. That should help significantly with the ticking noise.

You are not getting fuel pressure rise with boost. Best guess is that your vacuum line is not connected properly. If it is, then suspect a bad FPR. Base fuel pressure is 39psi and should go both above and below that based on your boost/vacuum conditions.

Since you don't have fuel pressure rise with boost, clearly it's not a fuel pump problem. It's a FPR problem.

I don't trust the 3.5psi reading. I suspect his MAP sensor is not set up right. 3.5psi will not blow off IC tubes, and your motor won't make 225rwhp with 3.5psi.

Either way, you need to confirm that the bypass valve is working properly, and that it is closing fully. Even a bad supercharger with a crappy porting job will make way more than 3.5psi @ 15% OD.

Correct your mechanical issues and try again. The tune isn't even part of the question yet.

12-06-2013, 05:07 PM
Thanks Dave. Got some work to do. Where is that vacuum line you are talking about?


12-06-2013, 07:11 PM
Thanks Dave. Got some work to do. Where is that vacuum line you are talking about?


fuel regulator hose is a ~~~~ to find.. mines off the return plenum nipple.. and hides down by the head right behind the return plenum next to the brake master.

12-07-2013, 12:18 AM
I did have a problem with my fp regulator. Figured a stock fpr would work, and it should have. Think a mud dobber made a nest in it. Same thing happened to my BAP. I found taking the return inlet to the lower intake out of the way I had enough room to replace it. If you do end up having a problem with the fpr. I would put a gage on it to verify. Mine was off about 6#. I know I personally have other problems with my car that still need to be ironed out, but that did make a big difference. I used a adjustable fpr from a 5.0. 3 bolt, same thing we have. Early model at least. I would ditch the cap head bolts and go with regular hex head bolts. Much easier with stubby wrench!

12-07-2013, 09:10 PM
Went down and saw Mike Puckett today. Spent some time together and he checked out my car. He is extremely knowledgable and a great guy!

Looks like my supercharger has a coupling issue. The pushrods are on their way and Mike believes that when the gentlemen who previously owned the car, when he put the new motor in he didn't plum all of the vacuum lines correctly.

When I pick up the 95, hopefully this week, we will swap the blowers and at that point tackle the pushrods and the vacuum lines.

Then hopefully it will be up to snuff!:D

Thanks again Mike!!!!!!!!!!:D:D

08-18-2014, 09:11 PM
Well the boost problem was solved and the car is running the way it should for the first time. Tonight the fuel pump was replaced and she drives great. I don't know what power she makes but she feels healthy. 250 to 270rwhp?. I will have to get it to the dyno and see. Not what I had hoped for as this is a new engine w/ different heads and cam. The car has a sweet exhaust, underdrives, 10% JS pulley, MPI, MP plenum, 58 lbs injesctors with a quarterhorse tune from DD, cam from DD. Heads are slightly ported with felpro head gaskets and ARP head studs.

It is a solid car and I can't wait to build upon this setup!!