Quik

iTrader: (7)

sorry but referring to a ls1 as a 350 is like saying its the same as a Gen I motor which it isnt

as for small, lmao

900 isnt high at all

cbrich

I pretty sure when someone calls a LS1 a 350 they are not referring to it as a SBC, but if you do then were have been for the last 8 years and what is your beaf against the SBC. When someone says they have a 350 LS1 or a 350 out of a 2000 corvette, and so on, I personnally know it is not a SBC that has been in production since the 50's, most of the people on here (or at least I hope so) and LS1Tech know that too. I have yet to read about someone trying to put SBC heads on a LS1, or a SBC crankshaft in a LS1.

thunder550

iTrader: (70)

Let's get back on topic and help him figure out his idle problem.

Is your tranny vacuum modulated by any chance? I had early shifting problems with mine because of that. Had to raise my shift points to like 6300 to get it to shift at 5900.

As far as the idle speed goes, the only thing I did initially when I re-flashed my tune for the larger engine is change the cylinder size.

4.8PWR

Maybe I just needed to drive it some, because the idle seems to have worked itselt out and now idles at the set 650. Now I'm having issues getting it to rev out first gear.

[Is your tranny vacuum modulated by any chance? I had early shifting problems with mine because of that.

Forgive my ingnorance, but could you explain this to me.

Also, I have adjusted the set screw on the cable operated TB, forgot to mention that earlier. And I believe I changed the displacement in the tune as well. The tune in it is just a starter tune to get it running. It's set to shift a 6000 at WOT. In first it shifts at like 4500, but pretty much revs second out.

By the way Quik, most motors don't equate to exactly what the call them.

And my LS1 is a 350 in my book.

thunder550

iTrader: (70)

Sounds like you need to adjust your idle airflow tables. Your computer will learn idle after awhile, but will only adjust so much.

Vacuum modulation in the tranny removes the electronic pressure control (removing control over shift pressures by the PCM) and replaces it with a vacuum modulated pressure control. Basically shift pressures are controlled by vacuum rather than electronically.

Quik

iTrader: (7)

yes i have the vaccum mod on my trans and if im low on vaccum the trans will shift goofy. i need to figure out something to help in this. espeically wien deceling down a hill. the trans likes to jump around some. something with my cam i guess i know i need to address this before the 408 goes in

shandy294

BTW did you know a 396 is really a 402? ..........sorry!

TigerFan187

iTrader: (1)

Did you get your idle fixed? Do you happen to have LT headers?

BenKey

iTrader: (1)

Did you get a stock tune or an already modified tune when you starting working on your tune? In what table are you telling it to shift @6000? What do you mean it revs 2nd out? Are you bouncing off the limiter? Have you adjusted the rev limiter at all?

4.8PWR

The idles has gotten better with more driving. The tune that is in it is for a buddys truck with a similar setup, except on a 5.3. I'm not sure which table he used to adjust the shift points, but he used LS1 edit. In first it seems to shift at around 5000 rpm (tho set at 6000), but it revs to the set 6000 in second. The rev limiter is set at 6200. Currently the truck has some Edelbrock shorty style headers, but Pacesetter long tubes are already on order. They should be in sometimes this week. As soon as the headers come in I'm going to let a local tuner have a crack at it as see what he can do with HPtuners on a dyno.

I pulled the TCI 3000 streetfighter converter out because it wasn't locking up correctly in overdrive. I've got the stock converter in it now. I ran nearly the same time at the track with the stock converter. With TCI a best of 14.5, with the stock one a best of 14.6. MPH was 92 with TCI and 95 with stock. Got a 2.1 60' with the TCI, and a 2.2 with the stock converter. This was done on 20's and street tires.