Frequently Asked Questions: Performance FAQ

[jmc007]

Originally Posted by socalsilverRL

Here is a question i got from the shortbus. The answer is kinda rough, but its general idea is correct. So, here goes:


Ill answer your Boost controller first:
No, boost controlers are for Turbos. The Boost controler messes with the wastegate on a turbo, making it think that there is less boost than there really is. Wastegates control how fast the exhaust turbine spins, and keep it from spinning too fast.

Boost:

well when you get into boost, you gotta know about how boost works, its effects on the motor, and octane gas requirements.

short answer: bout 21-22psi tuned VERY WELL on 93octane

Long answer:
boost is a byproduct of restriction in the engine (compression ratio, small ports, small valves, short diration cams, etc.), and the piling up of air being pushed in. Best way to think about boost, if by Cubic Feet per Minute (CFM). You can fit .5L or 31 cubic inches of air (actually less for efficiency reasons) in each cylinder, so when the blower is puting out 1L (62 cubic inches) of air to fill the cyl. then the pressure ratio is 2:1, or 22psi.

Thats why ported blowers, ported heads, and different cams will lower boost, but flow stays the same. Same amount (if not more) air, less cylinder presure, less stress on head bolts/pistons/rings/etc.

So what does that mean for the LSJ...

The head flows really well ont he LSJ, the valves are good size, and the cam duration is pretty long @ 262°. So everything is there for a good boosted motor. The only problem people have been finding on most engines, was blowing head gaskets, due to head flex/gasket failure, at 20psi. Thats why most switch to a better gasket, and ARP head studs instead of bolts. After that, you can put much more boost in the motor. Until the pistons/rings give out from too much cyl. pressure.

NOW...gas is what holds people back.

Normal 91-93 octane can only run safely, up to 22psi, ON AVERAGE, on a 9-9.5:1 compression ratio (CR), or less. Some are able to do 25psi...but thats on lower compression motors. Higher compression motors (11:1) cant usually go over 7psi. Beyond that, youll need somthing to lower intake temperatures.
When air is compressed, it heats up. Too much heat causes knock (when gas ignites before its supposed to), knock can destroy piston rings and/or pistons.

The drag Ecotec, is able to make 1800hp, running 24 psi, 10:1 CR?, on Methanol, with a dedicated water to air Ice-box intake charge temp cooler. They are actually able to run 24psi into the motor, at a colder temperature than whats outside. And the high octane quality of Methanol and power output, make that car's power.

Now, take that same HP and apply it to a 4g63 Evo motor. To get that, they have to run 32 psi, 9:1 CR, on 114 leaded octane gas (C14). Along wih the Air to Air intercooler, AND a Ice box as well.

The higher octane requires MORE heat (bigger hotter spark) in order to ignite the gas mixture, so it is less affected by knock condition. Thus, you are able to run more PSI/CFM into the motor. More Air = more power.

So...lets recap:
most people are able to run 21-22psi on their LSJ with 93 octane, tuned VERY WELL to eliminate knock.

If you plan on going with more PSI, or a Higher compression, plan on spending a LOT of money on:
1) 100 octane
2) Cooling mods
3) Methanol/Water Injection (cooling mod)
4) Nitrous (cooling mod)

According to the ECOTec Camshaft Info sheet on that page http://tunersource.gmblogs.com/Racer...ec-Tech-Topics cam duration (@ 1mm lift) is ONLY a tiny 196.5 degrees (intake) and 191.7 degrees (exhaust).

[socalsilverRL]

^ You are probably right, ill check and make sure.

I went ahead and cleaned up this FAQ.

If anyone has any questions or anything they would like to add... post up. Dont be shy.


Here is a good example:

Originally Posted by golden chicken

hey. in a couple weeks i'm going to be putting my B+G springs on. they were display springs so i'm quite sure there are no directions. i'm sure i can figure out the physical installation, but i've read that the bump stops need to be cut. where/how exactly should this be done? should i do front and back?

thanks.

Matt

Yes,
The rear you will need to cut exactly 1"off of the bump stops.

That will give you more travel on your suspension. The B&G springs pretty much ride on the bumpstops if you dont cut them.

If you are feeling like you are still bottoming out the travel, trim another 1/4" from the rear. The springs will settle from the initial install, about 1/2". WARNING: You must leave enough bumpstop to stop the springs from completely compressing. You do not want the coils to slam into each other at high velocity.

Advanced:
If you want to get rid of bumpsteer from the lowered suspension geometry...

You will need to unbolt your steering rack, and put in 2, 1" spacers and longer steering rack bolts.

This will bring your steering rack up (back in proper alignment), and help eliminate bumpsteer.

Reason:
When you hit a bump and/or compress your suspension, the steering rod angle changes because your steering rack is now 1" lower from the steering knuckle than it was stock.
The change in angle under compression, will cause your tire to turn out, also causing scrub (losing speed) in turns.

[rline06]

what can you do to your car before hptuners is needed?

Simple answer:
Almost any bolt on, besides a pulley.

Tech Answer:
Nothing. with any modification you do to your car, you should retune your car to make the most power from the new mod.

Like when you get a new intake, you should go back and log what the differences in MAF Hz and WB Air/fuel are, and recalibrate the MAF for your intake. Like if the Hz reads less, and the WB says leaner, then you need to scale down the MAF a tiny bit in the areas where the WB reads leaner than before, and the Hz reads less than before.

Or, for an exhaust, your AFR's will most definately change. Go back and retune your fuel, and then you may even be able to add more timing with less hot air being reverted into the cyl.


what do you have to do to run a 2.8?
you have to have at least 60# injectors to support that. A 2.9" pulley maxes out 42# injectors.
what if hp tuners is not available?
then your car will run like sh-t. It would be suggested that you find a tuner around your area that supports HP Tuners (look for F-body or W-body tuners).

does it help or hurt to take the resonator off?
does it add or take away horsepower?
no. it just makes your exhaust louder. It does remove a slight restriction in the exhaust, but the gains will be maybe 1-4 hp...depending on the amount of restriction.
-SoCal

[socalsilverRL]

updated...

[rline06]

what do i have to do to put nos?


whats the fattest tire you can run?

[thedubsack85]

Originally Posted by rline06

what do i have to do to put nos?


whats the fattest tire you can run?

i believe a 225 45 r17 on a lowered car.. i ran that size for DR's and has no rubbing issue's.
as for nos you have to either A) scream like vin diesel in fast and the furious. or B) tune for it and have a wideband gauge. and obiviously start off small and go from there or POP goes the motor. i know of people running a 2.9 pulley stage 2 injector's and the stage 3 PCM jus to have the 50 shot programmed into the ECU..and there jus fine..

[fullthrottle]

Whats better and easier safer to make power on Nitrous or Water meth injection?

you always have to ask hard questions, Mike...lol.

Either can make good power. Safer is solely dependant on how you build your car, and how you drive your car (with you, the emphasis should be put on the later...)... for you, water/meth is the safest bet. It helps raise our crappy 91 octane, and helps fight knock.

NOS is one of the safest/cheapest way's to get a crapload of power...IF...if you have a high tech setup that monitors everything for you, and has built in failsafes.
Examples of failsafes:
flow monitor
pressure monitor
tank level monitor
air/fuel monitor
detonation monitor

Same with water/meth. If you are running an extremly advanced and leaned out tune, then you may have a BIG problem if the tank runs out. There are a BUNCH of kits out there with 'built in' fail safes. They are exactly the same as listed above. If anything you want a tank level monitor.

On NOS, you want the failsafe to disable the NOS in the event of a parameter failure. On METH, you want your failsafe to disable the stock Boost solenoid (making the S/C bypass open).

Thats about the safest way to make power with alternative fueling.

-Socal

[rline06]

what are the best brake pads and rotors for the redline?

IMO, stock pads, GMPP slotted/drilled rotors
-socal

[Hypertension]

Not sure if this is right place, but I am running a bone stock '04 redline. I've been a full time student stuck taking nasty chem courses so I can't afford anything expensive right now with no job, but that the job part might change soon. My question is fairly simple, I hate waiting on the rev's to drop on the 1-2 shift and want a solution. I've read that jumping up to the stage2 (which I had always intended to do) seems to make this issue better, but I was thinking of a quicker fix that would have some small benefits along the way. My thoughts were to go to an 8.5LB flywheel. What would be the possible drawbacks/benefits of doing something like this? Has anybody done this and have an opinion on it? I've got little experience mechanically but I love learning when its not overwhelming. Any suggestions would be appreciated, and feel free to flame on me for being a newb, we all start somewhere, and at least im starting young!
--Hype

--Edited, had a brain fart and called it an 8.5" flywheel, lawl.

[socalsilverRL]

^dont do anything till i can answer your question.

Ok, so im going along with what qwikredline11 says below, just shift earlier. At first your question seemed confusing, but after seeing what other's said, they all said the same thing. Learn how to shift earlier/better. It will save you $$ in the long run. Once you blow through your stock clutch trying to learn how to shift properly, then go out and buy a clutch kit that comes with a light weight flywheel.