Engine Upgrades

[Storer]

My LS7 is currently a standard crate engine with a GM ECU.

Have others on here modified their LS engines themselves and if so what have you done and what was the power increase achieved.

I still want the car to be docile in traffic and she is not short of grunt but you can never have too much power.


Paul

[tjlees]

You can have a mild cam change + engine tune to give you a reasonable power increase. The more aggressive the cam is, the less drivable the car is in traffic. My original engine from American speed was excellent on the track but had to be kept above 2000rpm. This generated 700+ bhp with an ls7 and had very aggressive cams to get the air into the engine. I suggest talking to Charles Dunn or Paul at Wortec for help.

Putting a supercharger on keeps it very driveable and gives you lots of horses to play with
http://www.hotrod.com/techarticles/engine/hrdp_100... but means the engine has to be moved back by around 15-20mm plus lots of other work.

Another alternative is turbo charging http://schwartzperformance.com/gm-ls-engines/ but requires lots of the internals to be changed!

[macgtech]

Hi Paul,

One of the easiest upgrades is an increase in TB size, are you running the standard 90mm at the moment? You can go up to 102 (or maybe even 105?) without an issue. Obviously any gains could be limited by exhaust etc but its an 'easy' mod to make, just needs remapping.

Jonny

[F.C.]

tjlees said:

Putting a supercharger on keeps it very driveable but means the engine has to be moved back by around 15-20mm.

Not if you fit a centrifugal supercharger. proper steel internals are a benefit as would a lower compression ratio.
nice thing with a supercharger is how instant everything occurs, even at low revs.

[Storer]

I am reluctant to do anything that increases the weight (I am even trying to loose some myself) especially high up.
I know the power increase would offset the extra Kgs in a straight line but they would not help in the twisty bits.

Jonny
Where do you measure the throttle? I already have 102mm dia pipe but obviously the butterfly will be slightly smaller.
If it is the butterfly, where did you get the larger one from?

A change of cam is certainly on the cards but not for a wild one. 10% more than I have now will be just fine. If I want more later then I can dig deeper.


Paul

[200Plus Club]

i fitted a cam, timing chain and sprockets plus ls7 lifters and uprated springs/pushrods and retainers to my ls6 block. i'd never worked on a v8 before and found it relatively easy to get hands on, plenty of info and help out there on these engines.

[3Dee]

I have yet to see what my LS7 is like!

Non crate direct from GM (Via JS) - forged Mahle Motorsports pistons fitted by GM, honbed .005 to 4.130, then rebalanced.
Rod bolts changed to ARP, remachined heads providing 20 cfm extra flow, Mild Lunati camshaft reprofiled, dual valve springs:

Dynoed before shipping - maxes: 637bhp, 553 lb ft

Full IVA tuning this week + road map version...

All sounds nice, but we will see....

[F.C.]

Storer said:

I am reluctant to do anything that increases the weight (I am even trying to loose some myself) especially high up.
I know the power increase would offset the extra Kgs in a straight line but they would not help in the twisty bits.

Paul

26 kilo's including intercooler,pulleys,bracket and pipe work.

[DHGTR]

3Dee said:

I have yet to see what my LS7 is like!

Non crate direct from GM (Via JS) - forged Mahle Motorsports pistons fitted by GM, honbed .005 to 4.130, then rebalanced.
Rod bolts changed to ARP, remachined heads providing 20 cfm extra flow, Mild Lunati camshaft reprofiled, dual valve springs:

Dynoed before shipping - maxes: 637bhp, 553 lb ft

Full IVA tuning this week + road map version...

All sounds nice, but we will see....

Hi Keith
Where/who have you decided to go with for the tuning in the end?

Dave

[macgtech]

Storer said:

I am reluctant to do anything that increases the weight (I am even trying to loose some myself) especially high up.
I know the power increase would offset the extra Kgs in a straight line but they would not help in the twisty bits.

Jonny
Where do you measure the throttle? I already have 102mm dia pipe but obviously the butterfly will be slightly smaller.
If it is the butterfly, where did you get the larger one from?

A change of cam is certainly on the cards but not for a wild one. 10% more than I have now will be just fine. If I want more later then I can dig deeper.


Paul

It is measured at the butterfly, your best bet is to measure the plate itself as the TB is a bit of a strange profile. Do you run a cable TB or DBW? The cable ones are easily available - a simple Google search should pull up a good number (the FAST Big Mouth ones are popular), we currently run 92mm but are looking to go bigger (upto 100mm) and convert to DBW for a variety of reasons. I thought it may be possible to machine out the standard body and get a new plate made but because the profile is convoluted its a bit awkward - it is not a straight through 90mm hole to attack with a lathe!

[tjlees]

F.C. said:

tjlees said:

Putting a supercharger on keeps it very driveable but means the engine has to be moved back by around 15-20mm.

Not if you fit a centrifugal supercharger. proper steel internals are a benefit as would a lower compression ratio.
nice thing with a supercharger is how instant everything occurs, even at low revs.

Is that running it off the accessory belt? Usually better to run it off a separate belt directly from the crank due the 7.5k rpm you can get upto on the ls7. Also most supercharger producers recommend a 10 rib belt - that's why I said it probably needs to go back.

[F.C.]

tjlees said:

Is that running it off the accessory belt? Usually better to run it off a separate belt directly from the crank due the 7.5k rpm you can get upto on the ls7. Also most supercharger producers recommend a 10 rib belt - that's why I said it probably needs to go back.

Pulley ratios can easily accommodate 7.5 k rpm to max out supercharger rpm. (Bigger charger pulley is better for belt wrap anyway).
I have fitted a bespoke billet Ali "J" bracket and automatic tensioner assembly that gives as close to full belt wrap as you can physically get.
I run an 8 rib and there's still room for ten if required.
My engine is an LSX motorsport derived block and I believe is the same dimensionally as an LS7 other than the lugs for the six stud cylinder head arrangement.

[tjlees]

F.C. said:

Pulley ratios can easily accommodate 7.5 k rpm to max out supercharger rpm. (Bigger charger pulley is better for belt wrap anyway).
I have fitted a bespoke billet Ali "J" bracket and automatic tensioner assembly that gives as close to full belt wrap as you can physically get.
I run an 8 rib and there's still room for ten if required.
My engine is an LSX motorsport derived block and I believe is the same dimensionally as an LS7 other than the lugs for the six stud cylinder head arrangement.

Yes mines at least an LSX head, but separate belt drive hence why I have gone back 15mm. I did have choice of changing all the ancillaries to 10 rib but whipple convinced me to drive it from a separate belt.

[GTRCLIVE]

Storer said:

My LS7 is currently a standard crate engine with a GM ECU.

Have others on here modified their LS engines themselves and if so what have you done and what was the power increase achieved.

I still want the car to be docile in traffic and she is not short of grunt but you can never have too much power.


Paul

http://www.youtube.com/watch?v=Mz71ThIR3Oc

I have yet to order it but this seems to be the best Cam Only swap LS7 out there......and drivable as he proves at 1000rpm in 6th in a Vette thats 45mph

[GTRCLIVE]

http://ls1tech.com/forums/corvette-performance/125...

Read This.....

Edited by GTRCLIVE on Monday 5th November 22:34

[F.C.]

tjlees said:

whipple convinced me to drive it from a separate belt.

There's the problem right there.
You are talking twin screw s/charger = greater parasitic loss vis a vis bigger belt.
I have been talking centrifugal s/charger = much smaller installation = less room required.

[3Dee]

DHGTR said:

Hi Keith
Where/who have you decided to go with for the tuning in the end?

Dave

Hi Dave,

I have Paul Spinks coming up to me this week!
Will let you know how he gets on!

cheers

Keith

[chuntington101]

F.C. what supercharger do you run on the unltima? Procharger, vortec, Paxton?....

[chuntington101]

F.C. what supercharger do you run on the unltima? Procharger, vortec, Paxton?....

[F.C.]

GTRCLIVE said:

http://www.youtube.com/watch?v=Mz71ThIR3Oc

I have yet to order it but this seems to be the best Cam Only swap LS7 out there......and drivable as he proves at 1000rpm in 6th in a Vette thats 45mph

Really?
That's geared for over 300mph!
I'd have thought that would make fifth gear an overdrive let alone sixth!
My car pulls top gear from rolling tick over, which is just under 30 mph, (geared for 210 mph in top) sometimes I get lazy and don't change gear on large roundabouts when they are clear.
Point is it seems improbable that a (heavier) n/a car with an aggressive? cam and such high gearing would not bog down.