Thread: Why is my.. Top swapped car so damn slow?

I've gone over everything and didn't find anything too bad. The injectors aren't stock. You can see the heat shrink where someone soldered in new injector clips.. At least the **** was soldered. Leaves hope for the future.

I may be able to swing a trip to highway. Haven't been there in years.

h'ok, got some videos. Not sure if this is what you wanted, but it shows the ignition advance.
ACED1604-A948-4968-9651-9D85424656D8-15817-000013A4872401E5.mp4 video by Joshua_Ehlert - Photobucket
06968941-2841-41D3-A36A-0404DBDE81EF-15817-000013A571D2EDFF.mp4 video by Joshua_Ehlert - Photobucket

Thats a lot of WOT timing for pump/high comp bottom end.

Not saying its bad, but you could probably drop pulley size.

However you probably should figure the lack of boost issue first.

I'm gonna look into my lack of boost issue prolly next week. Can I close the boost bypass valve and do a boost leak test like on a turbo car?

I don't know too much about timing or tuning, so in that aspect I have a lot to learn. What does everyone else run for timing advance?

Can't really pressure test a supercharged car.

Just remove the lower hose from the bypass valve (BBV) actuator and cap it on the solenoid. Leave the lower nipple on the BBV open to atmosphere. That'll leave vacuum bypass in tact, but remove the traction control function. In other words turn off traction control if you anticipate wheel spin until you reconnect that hose.

You can go higher, but you're risking your head gaskets.

Not recommended to go much lower than 16 though.

Originally Posted by dsmuts

Didn't sound like WOT in the video

Did you watch more than the first second?

Originally Posted by winterstorm

the first video doesnt have WOT he probly only watched that one

When timing locks at 18.5, it really sounds like hes going WOT.

You guys...

Ok. Had some time today to look at the car. Turns out the electrical solenoid that runs to the boost bypass valve wasn't plugged in nor was there a plug for it. So I disconnected the bottom vacuum line. Car feels way better. But now I have kr. So I would imagine the boost went up (still haven't hooked up the boost gauge) but the kr scares me. I wanna say it hit 10 on a downshift. So looks like I have to order me some headers like yesterday.

If I order headers does that take care of the u-bend delete? Or is that a seperate mod? I'll also need the o2 extension harness correct?

Originally Posted by NegativeOne13

Yes headers will take care of the u-bend. Now another issue you may come across is majority of them don't come with cats. If your state has emissions testing, grab yourself a cat to put on there. Read the header thread, offers a lot of insight on headers. And since I did not see what year this vehicle was, 04+ need to have the O2 harness extended. If you are tech savvy, cut the wires and extend the harness yourself. I did it with some heat shrink tubing and soldering iron. Pretty simple.

They have emission testing in my state but I registered the car somewhere they dont require me to test so that shouldnt be an issue. Will I have a check engine light since there wont be a cat? The o2 emulator ( I forget where I saw it (w-body store?))will fix this right? I am very experianced with a soldering iron so I am very capible of making my own o2 extension harness (if required), Assuming its nothing more than just extending them. 10* of knock retard seems like alot to me. Should I remove the supercharger belt till I get a set of headers? For people coming into this thread late, this is a 2001 gt with a top swap. Man, you guys are helpful as hell..

I would setup the solenoid as it was before and run 3 psi again. At least you can have some boost in th mean time.

The aero can check boost. Setting is called map in hg/psi.

You will probably want a cat or at the least, keep your rear o2 sensor because you have a 2001. They like to run a cat diagnostic that dumps fuel killing fuel economy if you dont leave the rear o2 in place.

Originally Posted by matt5112

I would setup the solenoid as it was before and run 3 psi again. At least you can have some boost in th mean time.

The aero can check boost. Setting is called map in hg/psi.

You will probably want a cat or at the least, keep your rear o2 sensor because you have a 2001. They like to run a cat diagnostic that dumps fuel killing fuel economy if you dont leave the rear o2 in place.

I had no intention of deleting or eliminating any of my o2's. I just didnt want to run a cat. Im use to pre 95 cars and some of this is somewhat new. If I can get away with not having a cat id like to.

Pre 75 is pre cat.

If you keep the rear o2 and run a defouler on the rear o2 you should be fine.

Originally Posted by dsmuts

Pre 73 iirc is pre cat.

before and after you could have cats or no cats in canada. depends if built in canada or USA.

USA had stricter emissions, even in the 80's. We still didn't put AIR pumps on our cars in the 80's. Only in 88 did we start caring.

As for the tune, how is a tune seriously going to fix the mere fact that he's running too small a pulley with no other real modifications?

Unless you drown it in fuel and remove all of the timing, but thats just stupid.


I keep asking this, but GPF keeps assuring me that tunes are magical.

You know what I've found was magical? An intercooler. Literally nothing mattered with one of those.

But a tune? Had one by one of the most respected 3800 tuners. Wasn't anything magical.