Hi every one,

So I have an 03' w/ AT tranny
Vortech Supercharger................... ( everythings in my signature )
Just got it back with an SGP Valve body upgrade, and Tranny Cooler.
Stock Torque Converter

Stats Currently 367WHP 334WTQ

Any ways heres my problem.

When I am at a stop in Fake shift mode I call it, the car is crazy. I hurt my neck the first time I punched it b/c I had no idea. It even churps tires between shifts some times. However when Im rolling in say 4th even if I donwshift to 3rd and punch it I can literally look at the passenger and say, " dont worry it'll go soon." then wooshhhh! But theres a good 2.5-3 second period of WTF. Its like supercharger lag? I was wondering if any one else is experiencing that with there vortech kit on an AT.

Is it just the fact that I have an auto?

Do i need bigger injectors? ( i have 550's )

Do I need a better torque Converter?

So pretty much to some all of this up.... Im fast from a stop, slow from a roll.


Examples....

Example 1

I raced my friend with a Stock AT GTO from a 40 roll in 3rd. ( he only runs 13.1 at the track by the way ) By the time I took off he was 7 cars ahead of me? Thats the lag Im talking about. From a Stop light he got blown away.

Example 2

I raced my friend coming back from some place I dont remember where but we where cruising at about 80MPH, he drives a Heavily Modded SRT-4 ( he runs 13) Mind you the SRT-4 is a 4 cyclinder. We decided to launch at 80MPH thinking 350z V6 w/ SC no contest for his little 4 banger. He stayed right next me until we hit 140MPH and we backed off. RIGHT NEXT TO ME. Later that day we where at a light and when it turned green He took off, I spun tires for about .5s and then blew past him like he was in a civic.

What is this lag from a roll?

 

Does your motor at least begin to rev up. Or is your motor lagging.

 

Oh yeah It revs up, once it gets up to about 3,700-4,000 rpms the SC kicks in and off I go. But it's slow to get there, hense the lag. from a dig the power is instant.

 

How fast can you go in each gear? Does anyone know?

 

i think u are just in the wrong gears when u downshift. I notice that no matter what speed im in when I am in D and then switch to manual mode that it starts in 4th. If u are in 4th and u downshift to 3rd only when u going 30 then its going to climb slowly. I would recommand trying to downshift twice if u dont feel that kick bc I have stock vb and it goes fairly quick if u are in the right gear.

Off topic, is the sgp vb jerky when u downshift or upshift or in D?

 

The lag that you're talking about sounds like D mode when you mash the peddal, but the ECU needs a second to realize what you're doing and then drop gears for you. In manual mode, it's instant. Therefore, you're most likely in the wrong gear. I have a 5AT vortech and my top speed for gears are as follows:

1st - ~20mph
2nd - ~59mph (you HAVE to shift into 3rd to get to 60...it sucks)
3rd - ~95mph
4th - ~130mph? (guessing...never had to shift into 5th at WOT and I've gone 120+ before)
5th - ??

If you were going from an 80mph roll, you should be in 3rd gear. It will put you at about 4,750rpm and the car will MOVE. With the vb, once you shift into 4th, you'll be gone.

 

you have to stay on the high RPM when driving a Vortech.... You're not downshifting enough to stay in your power band.... It's like driving a Honda Vtec and must stay 4.5K RPM at all times. I think it's driving error and not the Kit. Remember below 4K RPM on a vortech is like driving a stock Car.

 

no it's not like driving a stock car below 4k, you're making boost as early as 1000 rpms, it's just not "full" boost

but yeah the vortech lives in the upper powerband for when you're really getting on it. If you bought a vortech for city town driving around 2000-4000 rpms only then you should have gotten the stillen SC or possibly a turbo

btw there is no such thing as "full" boost on a centrifugal SC - boost just keeps rising as high as your engine can possibly spin. It doesn't have a wastegate to designate where "full" is

 

Well put.

 

yeah comparing the vortech to Vtec is really not right at all.

Honda engines drive like fast reving economy cars then suddenly go nuts when the big Vtec cam kicks in

The vortech doesn't suddenly kick in like an on/off switch, it gradually rises up. the area where you feel it coming in strong the most is (drumroll...) where the engine naturally makes peak torque at. AKA, where the engine is the most efficient which is around 4000-4500 rpms

 

[quote=617G]The lag that you're talking about sounds like D mode when you mash the peddal, but the ECU needs a second to realize what you're doing and then drop gears for you. In manual mode, it's instant. Therefore, you're most likely in the wrong gear. I have a 5AT vortech and my top speed for gears are as follows:

1st - ~20mph
2nd - ~59mph (you HAVE to shift into 3rd to get to 60...it sucks)
3rd - ~95mph
4th - ~130mph? (guessing...never had to shift into 5th at WOT and I've gone 120+ before)
5th - ??

If you were going from an 80mph roll, you should be in 3rd gear. It will put you at about 4,750rpm and the car will MOVE. With the vb, once you shift into 4th, you'll be gone.[/quo

On the dyno ...4th gear ended at 143 mph

 

yeah the numbers I get with gear ratio calculators show that 3rd gear is around 5000 rpms

4th gear is a LOT weaker than 3rd gear. That's something I think Nissan messed up on a little with the auto gearbox. IMO there's too much space between 3rd and 4th gear. According to the gear ratio calculator with stock diameter tires, 155mph is the max you can go at 6600 rpms in 4th gear - compared to 105mph in 3rd

 

I had a gsr integra and the vortech and there is a similar feeling with the v tec and the vortech boost, more so with the 3.12 pulley.

 

Ok cool, well this is good news. That makes sense then if you can go up to 60mph in 2nd. So from a 40 roll I should be in second gear not 3rd waiting forever to spool up.

 

i'm always linking to this site it seems like

http://www.f-body.org/gears/

you input your tire size at the top (stock is 235/45/18 or 235/50/17)

input the redline rpms

then your gear ratios and final drive ratios

stock 5AT is:

final drive 3.357
1st 3.54
2nd 2.264
3rd 1.471
4th 1.000
5th .834



stock 6MT is

final drive: 3.538

1st 3.794
2nd 2.324
3rd 1.624
4th 1.271
5th 1.000
6th .794

 

Any one with a vortech and AT run at the track yet?

 

Oh yeah this is off topic, well I guess not it has to do w/ my vortech. Has any one had problems with leaving the car over night and when you turn it on the next morning it squeels while its warming up. ( Loud )

 

Yes. It's normal. Especially if it's been a cold night. It's just the belt. Once it warms up, it goes back to the normal clankity clank noise unless you've raised your idle. I've actually noticed that on a cold start, when my rpms are around 1000, the car sounds better than when it is warmed up and the rpms are at 600 or so

 

If your belt squeels when it's cold . It needs to be tightened up . If you dont keep it tight enough , it will slip when you boost the car !!!!!!!!!!!!!!!!!

 

cj350 has run 12.2