97 Vette big cam idle surge (first post to forum too )

[oldvette]

Hi Everyone been surfing the forum for years some great info here and thanks to u guys down under! anyway just finished my new motor and am having a few small issues that i thought you could help with! and u guessed it idle and surging.
Engine specs are 11.3.1 comp, solid roller cam int 632/236 ext 637/240 113 lsa ls6 intake, ported & polished throttle body with 2 1/8 holes drilled. motor is built to take 350 plus shot but need to get the little bugs fixed first.
am including a idle and a short drive scan and the tune in it now.

Thanks for taking a look and any help u might have!

[LS1_Dragster]

I'm no expert so I can only tell you what helps me.

I run 35 degress timing for idle and more at cruise then drop it down at WOT. You can see in your log that the timing is all over the place and every time the idle goes up it because the timing is up. I would just make the timing as stable and as much as the car likes.

Look at my tune for our dragster and you'll get the idea. Obviosly I wouldnt recomend this timing map for stock engines....

Also, your TPS needs adjusment. I think you've probably cranked your idle set screw to get it to idle. You need to back this back down, get the timing up and add air to the IAC.

Way too rich when on the throttle too.


Lee

[LS1_Dragster]

also, what size injectors? Your fuel map looks like this is a WOT setup, do you drive it on the road often?

I would also turn off the idle control stuff B5934, 5, 6

[98 tigershark]

Sounds like a good motor setup. What operating system are you running? 19980100, 19980200, and what tranny, trq convert etc. I have the specs for the motor? I have downloaded the logs and tune but will look at it later. Please let me know as I have worked allot with the 97-98 vettes. You have a dual fuel line system that runs the injectors at 62 psi, are they stock injs and a stock fuel pump? A 300 shot of NOS may not be supported with the current fuel pump but we can figure out the surging first.
let me know,
98 tigershark

[oldvette]

Thanks for the replies! and i forgot to give some info! 6spd with 3.73 gears
28 lb injectors with 64 lb pressure with in tank vertronix pump. 19980200 OS
i have it in sd no maf.

ls1_Dragster it is a vette no idle screw but i have been bumping timing up a little at a time

[98 tigershark]

Only a couple more questions. Did you means 2 1/8 inche holes drills in the TB blade if so how many? The idle tables and the air tables in startup plus the VE and the Closed loop tables are the ones we are looking at. Also what fuel do you run most of the time E10 or straight gas? When you get the car dialed in, I hope you have the larger head bolts installed and the block tapped out as a 350 shot would surely seem to want to lift the heads. That has to be like taking off on a rocket when the NOS kick in, pretty cool setup I think ( 2 stage?). Vertronix Fuel Pump? do you mean racetronix? Bosch owns vetronix and makes very good electrinic testing stuff so I know that that fuel pump. Also are you running the stock throttle settings( the ones you can only see when the cord is plugged in and are red and at the bottom of the list in the engine tuning section?
Let me know,
98 tigershark

[mr.prick]

Does an ETC TB need holes in it?

[98 tigershark]

That why I asked the size of the holes and the throttle settings. I have only seen this once in a none street application ( Drag strip only).
98 tigershark


Does an ETC TB need holes in it?

[LS1_Dragster]

Like I said "I'm no expert"! Never worked on a production vette. I didn't even know a 97 had ETC!

Even so, shouldn't the TPS be adjusted some how so it knows when it's in idle mode? Or doesn't it matter with ETC?

The cams not very big with your engine size to have so much idle air, in my opinion. I bet if you get the timing up and stable you will be able to lower the air values and have a stable idle.

[98 tigershark]

I understand where you are coming from but that is a very large cam for an LS1 in a 97 Vette or any other 97+ LS motor. It can be a TPS issue, but there is one table I have to take a look at first down in the Diagnostics where there is a needed change for big cams. Is oldvette using this for the strip mostly?
Thanx and you have some very cool cars LS1 Dragster.
98 tigershark


Like I said "I'm no expert"! Never worked on a production vette. I didn't even know a 97 had ETC!

Even so, shouldn't the TPS be adjusted some how so it knows when it's in idle mode? Or doesn't it matter with ETC?

The cams not very big with your engine size to have so much idle air, in my opinion. I bet if you get the timing up and stable you will be able to lower the air values and have a stable idle.

[LS1_Dragster]

98 tigershark - I somehow mistaked your engine for his! I thought he had a 427 too that's why I thought the cam wasnt overly large.

Thanks, I love doing resto mods and my wife loves the racing!

[98 tigershark]

I can understand as the cars you have done are very very nice and one would have to love it to do that fine of work and it also helps when the wife loves it too.
My cam does have an overly large duration but not lift intk or exhst ( very big compared to stock). I have future plans and this cam fit the geometry of what I am working towards.
I think duration is as important as lift when planning a project.
Also a blank L92 block is the exact same block as the LS3. These LS motors seem to need less cam than the LTs or so it would seem.
Take care,
98 tigershark