Common questions and answers
 

Figured I'd start this post for people to ask LSX type of questions on what parts work ect. This is not a "how much" type of thread.

Throughout the years I see people just throw money out buying parts that don't work. Everybody out there sell parts by "HP claims". Some work but a lot don't.

First- Headers

There is a lot more to them than just tube size, design makes a big difference on power/torque.

I prefer 304 stainless headers due to the long life. There are company's like ARH, Kooks and even TSP that have decent systems that will also last a long time.

The coated mild steel headers always rust and begin to rot. This greatly affects how the 02's work.

Tuning for headers- they can be tuned to pass emission testing- plug in test.

What about a list of brands in your first post that you prefer to work with when dealing with lsx?

MAFs-
The stock F-body MAF can easily handle 400rwhp without being a restriction. Pull the screen for 420-460rwhp which can gain 5hp.

A good upgrade is a GM 85mm MAF with screen. These can handle 500rwhp with no restriction. Over that you should be looking at Speed density anyways.

From a tuner's point

MAF's with screens are the best to tune. The screen straightens the airflow to make the MAF curve linier and easy to tune in at speeds/idle.

ported or the famous maf ends can be the biggest bitch to tune in right since the airflow is all over the place at different speeds. The fuel trims will vary by load/speed/idle. Can be tuned in to work OK but the difference can be felt at transitions which can be spotty.

ARH- if you have to have cats. The fit is great, no frame hitting and awesome ground clearance.

TSP- great budget header and fit's good if no cats are used. Some welding is required if you want a leak free fit.

First suggested bolt-ons

M6 car-
Air lid
cutout or cat-back exhaust
headers
Gears


Auto car
air lid
cutout or cat-back
headers
stall converter
Gears

How about a ported throttle body

posted a question in the 4th gen section yesterday, my car being an A4, what are the pro's and con's to a 9inch vs a 12bolt? Thankyou!

Ported throttle body is a 6-8hp/4-5tq gain on a stock car. Good mod.

Now watch out for - over ported throttle body's. Seen a lot of them. They will cause hanging idle's ect.

epoxied vs reg ported - no hp gain with epoxy. Might look better but I have seen the epoxy fall out before and get sucked into motors.

There is really no difference for your combo. 9" can be a stronger rear with the correct parts.12 bolts can handle 1000hp too.

Now, how they fit and the correct suspension angles is a different story.

We recommend Midwest 9". The rear is built correctly, suspension angle's are spot on and it fit's in the car without hitting anything. (unless lowered a lot)

So I am guessing that the ported maf ends I just put on are no good. Didn't pay anything for them. My buddy went carb setup.

I'd make you put the stockers back on. De screened stock at least gives you some separation.

You can see the issue by tuning it, then turn the meter 90' and log again. The load tables change.

Your car with the tranny is at the point of being OLSD tuned anyways. It would help a lot with the stall, cam ect. Throttle response will be better and more consistant on nitrous pulls.

What's a good clutch for a h/c ls1? Also what heads do you recommend for an ls1?

Good to know. I will inquire about it tomorrow. I am bringing my stock maf with me too

We like the Mcleod RXT. Stock peddle feel, easily drivable and handles 1200hp. Means you won't need another clutch again.

Heads have a lot of variable's depending on what it is for.

Stickied! Thanks Don!

Cam-
This is a big problem for most. Picking a Cam off an idle video or the highest internet numbers is definitely the wrong way to choose.

A lot of factors when picking a Cam.
1- Auto or manual tranny
2- gears
3- heads/intake/exhaust setup
4- what is the car being used for
5- how much drivability are you willing to give up.- This is opinion since everybody has a different standard of how they drive.

Most street cams want a strong midrange torque curve with a shift point of 6500rpm or so. These cams can be an easy daily driving type of cam.

People with 4.11+ gears M6 or 4000 stall A4 might prefer a bigger cam which put's the power curve to 4500-7000rpm. This will pull up top most but most of the time are harder to drive daily due to crap idle.

A few basics.

Don, best way to choose tire sizes and also best tire for a street strip car?

That goes by gear ratio,tranny and suspension.

Tuning, when and how?

Tuning can help pretty much every stock car. The factory dumps 1 tune for 200k+ cars. The computer does it's best to self learn and does a decent job.
Tuning will bring out better throttle response, drivability, faster 1/4 times with TM deleted and better fuel/timing tables.

Shops- There are a ton popping up nowadays. You have a wide selection to choose from. Do your research on each and go by how long they have been tuning just GM vehicle's. You really don't want to be there test vehicle without knowing it. If they prefer hand helds- walk away.

Tune types
closed loop-,maf,02's - Most common tune, good for stock, bolt-on's and small/medium sized cams. This usually consists of tuning the MAF table in for fuelling by going off l-trims , setting your own timing table and various little changes. Tune time- 2-3 hours

Closed loop, SD base, put back 02/maf - This is for bigger cams 228+ duration. Setting a SD tune helps with transistions with the cam and makes a more drivable bigger cam car. Tune is the same above with the added VE table tuning. Tune time- 3-4hr's

Open loop speed density w or without 2/3 bar- This is a precise tune mostly for huge Cam(low vacuum) or Forced induction cars. With some of these cars the MAF will fluctuate too much causing fuelling problems and the 02's will give false readings due to overlap(raw fuel). The tune has to be precise in the VE table and timing has to be spot on with forced induction cars. When it is all set no adjustments are needed. Even for weather ect. Finding a shop that knows how to tune this way is difficult. You need a load dyno or risk tickets on the street. tune time 5-6 hours due to cold start situations.

Remember- always try to have a well tuned up car before bringing to a tuner- good plugs,wires,fuel filter. A lot of times the tuners are blamed for the owners lack of responsibility and maintanence.

for a street strip car what do you prefer for a shock and sway bar set up

I like rear track bars but it might be too extreme for corner carvers.

Street you can get away with BMR or hotchis sway bars and pull the front for the track.For ride quality I like the BMR springs with stock shocks.

M6 would need a bigger tire to hook but an A4 can get away with a 10" ET street or DR with the parts listed above.

On my personal car I loved the stock shock/springs and BMR track bar- no front sway bar. It could take 70mph off ramps, was stable and hooked like a bastard.

Good info about finding the right tuner. Just went through this. It took me a long time to trust somebody with my car. I called a bunch of places and did a bunch of reasearch online too. After talking by text with you the other day it seems my guy did a good job and did what he should of done. The car drives great and has great cold start and idle. Especially with a 236/240 cam. LOL.

Don I will say one thing. The knowledge you bring is invalueable to us and this site. Thanks for everything!

Thanks Justin. I try to just pass on what we've already tested/done to hopefully save all you guy's time/money.

Tuning is the hardest. It's hard to understand why I question tuning so much unless you were here everyday to see what rolls in. Got one recently that when you floored it the car would just cutout due to being flooded in the tune. Guy paid $800 and brought it to the shop 3 times to fix the tune. It was a simple fix that we squared away in 15 minutes for him.

Just don't want to see anyone get raked.

I hear ya man. Thats why I was so freaked out about having someone else touch the car. I have heard your horror stories in the past. I know some people dont like when people are upfront with them, but that to me is better than beating around the bush. Not for nothing I know my car isnt a crazy setup but with the trans swap/cam/injectors/nos I was panicing a bit. Once he got the cold start and N/A tune spot on I started to relax. Thanks again for checking in the other day.

How about SFC's? What are the main differences between weld in and bolt in

Don knows how to put together a powerful engine that is bullet proof. I think I've been racing on mine for 8 years now since he setup mine and never had any problems with it (knock on wood). I see day in and day out other cars at the speedway running into issues here and there. I know I don't know what I'm doing in my engine bay, so I don't touch it.. lol.

Squeezing out a few more HP out of my current setup might help me a little at the speedway. So I should consider a ported throttle body?

I got a heads and cam setup. Kooks headers with catted ypipe.

My main problem is launching consistently on my m6. I just put in a short style torque arm and LCA relo brackets in the middle hole. I should give the bottom hole a try.

No problem, just wanted to make sure you were happy. There are plenty of tuners that know what they are doing and looks like you found one in your area.

The biggest issue I see is that some people think we are here to just cater to people with money. The fact is 90% of our work is just regular people saving up for mods.
I like basic builds.

Weld in is a more solid connection and most times a lighter setup. Bolt in work but rely on the bolting spots for strength and should be checked a few times to make sure the bolts don't back out.

I prefer BMR weld in. They are light and tuck up under the car nicely.

What about the Bolt-ins and then welding them? FYI the SFC that you installed in Michelles Z have been perfect. I think those were TTP prototype? from sometime ago.

Bolt in while welding is just fine. The downfall is usually the weight. So,if ordering I would just go weld in from the start.

Some people will get bolt in then bring it to a place to weld. That place has to pull them off to clean the paint off. So,no money saved.

Torque arms? How useful are the relocation kits? Benefit of adjustable vs non adjustable?

Torque arms do 2 things. They make it so you can adjust pinion angle and instant center.A non-adjustable bar just adds a little strength compared to the stock bar.

Relo kits are made to adjust instant center points. They are commonly used when you lower the car to get the control arms back to the stock angle.

Instant center point reference can give you an idea on how a car will hook.
This is measured by a straight edge on the torque arm towards the front of the car and also the LCA's. Where they intersect with each other is the center point. Of course you pretty much have to eye ball that out.

Lowering the control arms on the rear will bring the center towards the car. This can make the car hook better on ignitial hit. Too much is very common. That's when the car hooks good, can do a quick pull of the front tires,then spins a bit or bogs hard. It pretty much bounces the rear tires. Too much can also give a lot of wheel hop.

With the instant center too far out the car will just spin a lot and not even try to hook. You really want it to load the rear wheels but not too much.

An A4 car has a lot more room to set this up. A M6 has to be played with till it's spot on. When right the car will spin very slightly for 10-20' out while producing the best 60'. At no time the front will pop up for a split second.

There is a lot more that goes with this on front suspension lift times ect but I think we hit the LCA, torque arm part. LOL

Thanks im just trying to learn about suspension as i go. So for a bolt on/cam car what would be ideal?

Auto or M6?

Auto

If it dead hooks, there is nothing to do.

If your upgrading I would add double adjustable LCA's first.

Before I ask I would like to clarify that I am trying to adhering to my class rules for Autocross.

Don would installing my Fast 90 intake/TB on my stock motor with my headers be worth the hassle for that little gain. Would the 285cfm hurt me because the motor is stock? Could you guestamate the gain or loss? Or should I just get my stock TB ported.

I've seen 0 gain and even a loss of a few hp with a FAST on a stock motor.