QUESTIONS FOR LS1 EXPERTS

[c5ragtop]

There seem to be a few of you knocking around here who know a lot about the LS1 and how to tune it. I'm no expert but I want to enhance my Vette. What do you guys think - am I on the right lines or not. I don't want to open up my engine with cams or porting etc nor do I want to bolt on Turbos or Superchargers as I want to get my car out whenever I want to and know it's going to bring me home again. This is what I have in mind:

LG Motorsports LG Pro Longtube Headers with high flow cats. These seem to be the ones recommended the most on the US Corvetteforum
www.lgmotorsports.com/catalog/product_info.php?products_id=932

Corsa Indy with Pro Series tips. The Corsas seem to boast the least resonance when cruising which appeals, yet the Indy option is louder on acceleration. I would guess that with the Longtubes it's going to be quite noisy anyway. I've chosen the Pro Series tips as they have a gap in the middle for the tow eye on my Vette.
www.ecklers.com/product.asp?pf%5Fid=38783&dept%5Fid=1778

Halltech Stinger air intake - simple to fit and doesn't run the risk of sucking up water like some intakes. I had a Blackwing before but my engine seemed to stutter with it.
www.lgmotorsports.com/catalog/product_info.php?cPath=342_224_456&products_id=1463

I have received the following comment from one supplier - can anyone tell me what it means please:
"... on the (97-03) C5's I do suggest running the rear sensors in the front location because they have a higher wattage heater circuit. Once this is done I would suggest doing a tune on the car which we can do for you via UPS or FedEx."


Rightly or wrongly the above is what I'm thinking about. What do the experts reckon???

[franv8]

Think the last bit is he's talking about the heated O2 sensors, C5's have one in front and one behind the cat (the brain checks the cat is working, unlike on the C4's where it only has one in front of the cat, or really nowadays, in front of the long pipes where the cat used to be...)

One tuning extra you haven't looked at is the low drag bonnet option, in one colour without the flappy flaggy thing.

[anonymous-user]

franv8 said:

One tuning extra you haven't looked at is the low drag bonnet option, in one colour without the flappy flaggy thing.

Ouch!

[te51cle]

I think Jason had Corsa Indy's when he brought his C5 to the Fish Inn a year or so ago, they seemed quite loud to me !

[vetteheadracer]

Hi Rich,

I am planning on calling in on Lou Gigliotti at LG Motorsport when I am oer in Texas so if you want to talk to him about anything then let me know and I will happily ask him.

I was going to fit the LG Long Tube Headers on mine before I was lured to the dark side.....

As an engine is basically an air pump, putting more in and making it easier to get it out will always make it faster so you are definitely on the right lines for what you want to do.

>> Edited by vetteheadracer on Saturday 22 April 08:51

[c5ragtop]

Thanks Nige - I'm still confused about the sensors and what sort or tuning or reprogramming is required. If the rear sensors test the emissions after the cat, surely it's going to throw up error codes if they are moved in front of the cat. Perhaps you could ask him to explain.

Those that know me will realise that I am very cautious and this is new ground for me. I don't what to do anytning which is going to cause me inconvenience or hassle. I admire the resiliance of some (like Nige) who in the face of adversity keep coming back for more - I suppose it keeps the mileage down.

There's no need to ask him about the flappy thing as suggested by one "contributor".

It would be great to hear what Boosted and others have to say.

[michaelz16]

Rich
I put in LG long tube headers and BB bullet tailpipeson the Z. I also installed hi-flo cats. I'm now deaf but the low end torque increase is very good and, combined with the Vararam intake I raised hp from 392 to 433 and torque from 385 to 422 ftp. If you go to www.ls1howto.com you'll get a blow by blow account of installing the headers plus other goodies.
Don't get hung up about O2 sensors. The boys at LG are extremely helpful and will give you tons of advice on the phone or e-mail.
As far as LS-edit or hand held tuners are concerned my personal view is that there is alot of hype and bs talked about those things. If you go for the headers, put the car on a rolling road before ( to baseline) and after the install. That way you will see the real difference and if you use Surrey Rolling Road he'll interpret the A/F ratio to see if you do need a tune.
Presumably this need for speed has nothing to do with coverting the "Fasted Kid in the Valley" trophy does it?

[te51cle]

Just had a look at the specifications, the LG 'Pro' long tube headers say they terminate as a 3" diameter pipe whereas the Corsa exhausts are a standard 2.5" diameter. The LG 'Street' long tube headers terminate as a standard 2.5" pipe.

[Gixer]

Can you still get headers from Jeal??

[V8D]

Hi C5ragtop. I am looking at the same options at the moment for my C5. I think the best way to go about this is as follows. Decide on your combination of exhaust, headers etc, and whether you are going to decat it, etc. Pick a decent intake. Most of this would probably be best done by recommendation from folks who have done it, and a bit of personal preference. If you decat it, you will have to fool the pcm into thinking the post cat Lambdas signal is plausible, or knock out that code with EFI live or whatever. Next, you will have to get the VE table edited to reflect the new breathing ability of the motor, otherwise the pcm will incorrectly fuel in SD / open loop mode (WOT) and the benefits of the better breathing will not really be reaped. PCMs are quite good at detecting mods as faults due to "implausible" sensor signal combinations. A good tuner with RR will do this easily. Once done, you can then start editing the fueling and spark tables to give the optimum afr and timing at each rpm/load combination. Again, on the rollers. Sounds simple, but you need the assistance of someone who knows what they are doing to get the best result. I am personally very sceptical about the one cap fits all tuning gizmos as all cars are different, and combinations of hardware mods need different software changes.
Take your time, talk to all the acknowledged experts, and you will start to see the common threads emerging. Then you can make informed decisions. A very nice chap I met at the Crispin in the week told me that the C5 Auto box isnt the strongest, and that one shouldnt go over 400bhp or it will break. Havent researched this yet, but probably best not to go too mental with the hp till we know for sure.
Just my thoughts, hope it helps.

[Boosted LS1]

c5ragtop said:

It would be great to hear what Boosted and others have to say.

Sorry but I can't help here, I'm engines only From what I've heard, long tubes are a good option for the vette as is an uprated MAF, intake system etc. Downside with production cars is they may need an ecu tweak which can be a pain. StevieT would be the chap to ask

boosted

[c5ragtop]

Thanks guys and particularly Dave V8D - plenty of food for thought there. Also Boosted who took the time to send me a couple of emails.

Also good point Tristam - I suppose a big smear of Gun-Gum wouldn't work.

>> Edited by c5ragtop on Sunday 23 April 10:18

[vetteheadracer]

On the subject of tuning I have tried the LS1Edit and it's not very good IMHO. It also cost $600

I would invest the money using someone like Raceshack (the guys that sorted out my tuning) as they should be able to tune the car or advise what to do.

[franv8]

The second O2 sensor (the one behind the cat) can be relatively easily eliminated by a plug in device that 'simulates' the signal - I'm sure it's in Ecklers and the like, so the brain still thinks everything is hunky dory.

As for matching tube sizes on headers, there is an explosion of custom exhaust fabricators who would be able to help on this, particularly if you wanted 8 4" stainless tailpipes, or perhaps one enormous oblong one the width of the car.

Despite that last comment it seems that there are definitely some who do a quality job.

[Camaro SS]

Best place for tuning a GM ecu is Fastchip in Oklahoma, just has the SS done again due to lowering compression and adding supercharger specific cam, great job done, sent by Fedex on a Wednesday and had ecu back in car following Tuesday. Have not found anyone over here that can deal with mapping, we took the ecu for the pace car out to the States and that was mapped by Arlington Motorsports (don't think they exist now) using LS1 edit. They do so many mods in the States that they do seem to get the best out of an ecu because of their experience and volume of cars they deal with.