L98 Cam suggestions?

[Nick90vetteguy]

Starting to do some research on Cams, I have no idea what I'm looking for, just somthin similar to the stock cam, a ton of low end torque and mid range power, and possibly thinking about 4.33 gears?

 

[vetteoz]

I have no idea what I'm looking for, a ton of low end torque and mid range power,

Sounds like you need the stock cam
If you read the many similar posts on cams ,it is not just a matter of " throwing a cam in".
Cam has to match and work with all the other engine components.
You need a PLAN
What do you want from engine , how much $$ you prepared to spend?

thinking about 4.33 gears?

Wrong
You want a low revving , bottom end engine and low gears?
Get a online RPM vs Speed calculator ans see what revs you will run at what speed with those gears

 

[WhalePirot]

SCam has to match and work with all the other engine components. You need a PLAN

Being unfamiliar with all that when I redid mine, this is GREAT ADVICE and can make the difference in results for your money spent all or more that your wish, or a disaster. A great shop or builder can help define what you want.

In my case the longer stroke of the 406 (or a 383) gives plenty of torque, which is what I love (see 'acceleration' in Webster's). I spoke with Comp for a cam recommendation when I built the 383 Corvette engine for my old Ford truck.

 

[Nick90vetteguy]

Vetteoz what would I do with out ya? honestly I just want something I can get that "choppy" muscle sound, I understand airflow and exhaust plays a part, I have headers and a high flow cat with eliminators, but I just like that idle crunchy sound, thats what I'm trying to go after but.

 

[vetteoz]

I just want something I can get that "choppy" muscle sound,

Problem is ,
the sound you " want" is achieved with a cam that is the complete opposite of one that gives bottom end torque and passes emissions.
The idle lope of a perf cam comes from the longer duration/ valve overlap which allows a engine to breath at higher revs by holding the valve open longer.
Best I can suggest to give muscle cars sound for a stock(ish ) engine is the ZZ4 cam.
Often available as a new engine take out for under $100

 

[WhalePirot]

I just want something I can get that "choppy" muscle sound

My car idles just that way but it pulls real hard 'down low' due to the longer stroke. That lumpy idle keeps the ricers from making eye contact at traffic lights; perfect!

 

[Nick90vetteguy]

oh bummer, well I'll just keep my stock cam I love it anyway, btw if I were to install a upgraded set of fuel injectors( I think the stock is 22lb) what would be a good range to replace the stock? 24lb? :eyerole

 

[WhalePirot]

if I were to install a upgraded set of fuel injectors( I think the stock is 22lb) what would be a good range to replace the stock? 24lb? :eyerole

Remember that the engine needs a certain amount of fuel for a given amount of air. The ECM constantly adjusts the injector pulses to achieve that. Changing the fuel pressure or the injecftor size will mean the EMC will counter that change, to the limit of its 'authority'. Changing the rated flow upwards may make your car run rich and might even foul/plug the cat.

If you want some improvement or are aching to spend some dough, I'd look into hot-coated headers and a more open exhaust. There might be enough seat-of-the-pants change to please you, for a while and when you decide to do more with the engine, you'll want them anyway.

 

[Nick90vetteguy]

already got em, heddman hears long tube with magnaflow high flow cat,

 

[vetteoz]

if I were to install a upgraded set of fuel injectors( I think the stock is 22lb) what would be a good range to replace the stock? 24lb? :eyerole

Pointless
Engine is not going to make more power
If you install a larger injector ( and get the computer reprogrammed to suit ) the computer is just going to open the injector for less time than it would with the smaller injector to spray the same amount of fuel required .

Think you need a gal of water ;
doesn't matter if you turn the tap on full or on 1/4 , you still need a gal

 

[KANE]

Wrong

Pointless

I'm going to go out on a limb here... but for a stock engine where the owner wants quicker acceleration- yet retain the factory heads- what would you recommend? In addition to the ZZ4- what else? Big picture...

Budget? Sounds like the OP is willing to drop between $1k and 2k judging by his comments of a cam and a gear.

 

[vetteoz]

. but for a stock engine where the owner wants quicker acceleration- yet retain the factory heads- what would you recommend? .

Higher stall ?
Lower gears ( dependent on what ratio and trans he has at present)
3.07 gives a good SOTP feel over stock 2.59's in a auto TPI while still giving good economy

 

[boomdriver]

I'm going to go out on a limb here... but for a stock engine where the owner wants quicker acceleration- yet retain the factory heads- what would you recommend? In addition to the ZZ4- what else? Big picture...

Budget? Sounds like the OP is willing to drop between $1k and 2k judging by his comments of a cam and a gear.

My list comes from personal experience and having financed most of the aftermarket operations in the country.....:eyerole

Exhaust systems. Larger front Y, free flow cat and good mufflers or eliminators. Long tube headers. Shortys are a waste of time...same as you have stock. It came with a shorty header thats better than a cast manifold but not as effective at scavenging as the long tube.

Equal attention to the intake...
Simple clean up of the plenum ports, grinding out of the throttle body ports, matching runner ports with gaskets/runner flanges.Stock runners that have been internally opened, or some SLP or Edelbrock runners that will help thru the whole rpm range. Port matching does as much as anything as far as intake mods.When you have 3mm lips/edges inside a 25mm runner, thats a significant disruption in the airstream.
Add a 52mm Throttle body AFTER the exhaust is done and the plenum has been opened/bored.

NO throttle body air-foils (absolute junk, even dangerous)

The addition of a t-body spacer won;t hurt if low-mid range (street performance) is the goal. K&N filter with airbox lid cutout, and/OR a real induction system that uses science to shoot air thru the throttlebody and not colorful advertising names/claims, gimicks. When its all said and done the K&N with an open lid is just as effective, just not as pretty.I went back to the open lid because of various issues with aftermarket systems. Because of the "pretty means fast" factor, I polished the aluminum and that thing jumps out like a diamond Rolex sitting on the black radiator shroud!
Pretty yeilds credibility for some reason...

Adjustable fuel pressure regulator, and finally a REAL TUNE by someone with a dyno that has the software to adjust and maximize the engines potential with spark curves, timing against fuel pulse, air, etc. That all by itself often frees up to 20 hp and with the other mods in the above list, might give as much as 30.Thats a substancial increase and combined with better throttle response and sometimes better fuel economy, its a winning project.
With ALL that stuff, you MIGHT benefit from 24# injectors but the tune would have to come last ! Adding bigger injectors does more harm than good if you cannot add more air. The fuel/air ratio of 14.7 :1 MUST be maintained for optimal performance. See the link for detailed understanding of why we have to follow that rule when "upgrading" our engines.
The Stoichiometric Air-fuel Ratio and how to calculate it

A great example ,, a top fuel dragster consumes 11 GALLONS or more of fuel in 1/4 mile. That is because there is soooo much air being force-fed to the motor and that type of fuel demands that much air be delivered so the correct ratio will be maintained. Consequently, if you added a super-charger to your stock engine and nothing else, it would not run well for the same reasons. The fuel/air ratio would be off.

There's about $2500 in this list. From there the numbers grow exponentially. Double each $ amount to take the next step.

There must be a mathmatical equasion for engine enhancements...a formula that tells you how much $ to go how fast.

All this does not have to be all done the same weekend, but can safely be done one piece at a time. There will be a point where there seems to be no change or improvement until you do the next thing and BOOM!< it suddenly all comes together and it feels real cool ! For me, it was the big exhaust and freeflow cat. I almost fainted when my motor suddenly started to rev idle to 5000 instantly..not the usual slow buildup or hesitation that the stock motor has. Instant...it was exciting to say the least..
If the savings acct permits......later on do full roller rockers, springs with the new cam.

As Vetteoz and the others have already said, there is no single thing to do, rather a combination of things. Parts have to work together, be compatable and above all, the owner has to have a goal and a target to work toward. Just sticking parts together will not make a faster car. I have seen guys buy heads and cams and headers and all kinds of other stuff, and end up with a car that was a slug.

Ever seen someone stick a HUGE 4 BBL carb on the stock chevy 283 or 350 (we all did it in the 70's) and get a loud Bogging sound as the gas pedal is floored, but virtually zero pull or accelleration. Just noise. Because the sudden rush of air screwed up the intake flow dymamics, therefore the fuel/air ratio...its a failed enhancement.

The above list also maintains the factory parts whenever possible, and that will keep the reliability up there with the stock motor. Its common for guys to trade away some reliability for performance and thats fine, until it breaks and makes you walk home. The way newer cars find even more HP is by way of more precise engine mngt and a better assembly process, like hand assembly instead of the casual line assembly of high production lines in the past. The ZR1 motor is assembled in what amounts to a "clean room" like you'd expect to see at a micro-chip mfg facility or NASA.
Attention to detail yeilds 2% or 3% gains in various places. It ALL adds up in the end to make REAL power and performance. Thats also reflected in the selling price of late models...

The factory design is very solid and it was designed to last a long time. The downside in assembly line production where details like casting ridges inside intakes, or small tubes in the exhaust reduce what the overall package can potentially do. If you simply improve and clean-up the original parts then you will keep a dependable car and get one thats more responsive and fun to drive.

-------------------->> WARNING <<-----------------

Once you go down this road to performance enhancements, you;re never coming back..! Many good men have traveled this path never to be seen again...:ugh There is no known cure either...

You could be lost forever in the garage pursuing performance...


Good Luck...just remember, its all about having FUN !

 

[Nick90vetteguy]

WHat do you think about 58mm throttle bodies? I'm thinkin about taking mine off an puttin the 52 back on, I feel like the air isnt flowing smoothly like is bouncing when it gets to the penelum. I cleaned my old one with carb cleaner took a dremel and polisher to clean it up looks brand new

 

[WhalePirot]

WHat do you think about 58mm throttle bodies? I'm thinkin about taking mine off an puttin the 52 back on, I feel like the air isnt flowing smoothly like is bouncing when it gets to the penelum. I cleaned my old one with carb cleaner took a dremel and polisher to clean it up looks brand new

Size matters. The BBK 52mm on my 409 works very well, all the way to 6300 RPM, so the 58 is probably too much for a 350.

 

[vetteoz]

WHat do you think about 58mm throttle bodies?

Another waste of $$$ on a stock ish engine running lower revs
I did 30 back to back runs on the same day on my mild TPI setup ; ported plenum , big tubes , siamized base , LT's

1/2 with stock TB ;
1/2 with 58mm TB
Absolutely no difference so better to spend $300 on something that actually may give some benefit ( as a side note, engine did not die as predicted by many if you use a too large a TB )

58MM on stock plenum is even worse because TB is bigger than plenum opening ; just creating turbulence behind TB

 

[Nick90vetteguy]

Problem is ,
the sound you " want" is achieved with a cam that is the complete opposite of one that gives bottom end torque and passes emissions.
The idle lope of a perf cam comes from the longer duration/ valve overlap which allows a engine to breath at higher revs by holding the valve open longer.
Best I can suggest to give muscle cars sound for a stock(ish ) engine is the ZZ4 cam.
Often available as a new engine take out for under $100

Hi VetteOz, I have a question, so If I were to obtain a sound with a performance cam, what mods would I be looking at? and is it more top end hp?, thanks

 

[boomdriver]

WHat do you think about 58mm throttle bodies? I'm thinkin about taking mine off an puttin the 52 back on, I feel like the air isnt flowing smoothly like is bouncing when it gets to the penelum. I cleaned my old one with carb cleaner took a dremel and polisher to clean it up looks brand new

Like vetteoz says....its a waste of time/money. 52mm TB on 48mm ports does nothing well. if anything, creates drag or turbulance that disrupts the flow to the runners. You have to open the intake/ports/cyl bore and the exhaust before you can expect ANY benefit from a larger TB. The plenum TB bore has to be opened or the trouble starts 1" behind the new TB..
A naturally aspirated engine is totally dependent on vacume in charging the cylinders and if you play around with the dynamics of the throttle you can actually lower the size of the fuel/air charge thats entering the cylinders. Decrease performance.

58mm TB is fine, on a motor thats bigger internally AND has heads and an intake that can handle the increased volume.

To get a better understanding, suck on a straw and feel how much vac you can create...quite a bit, because its a smaller area or volume. Now suck on a garden hose. Not able to get the same level of vac on that with the exact same method and amount of suction. Now, knowing this, add the fact that vac is what actually moves the air & fuel charge...Your pistons can only pull so much with each intake stroke. if the TB is too big it slows the charge down. The tricks are in the size of some intake parts (like the TB bore) so that vac is created at the right time and place so it speeds up and enters the open intake valve as fast as possible so it jumps into the cyl to get the max charge in there.

If the rest of the motor is stock, the TB probably should be as well,. at least until other mods have been performed.
Like I said before, mods have to be done in a plan, together to acheive a goal.

 

[WhalePirot]

a performance cam ...... more top end hp?

That term is not specific. What IS a performance cam? Engines, built properly, suit a rather specific purpose and the stock Corvette engines have emphasized either lower end torque, like the L98s or give up some grunt for higher RPM torque.

Remember, HP is mathematical product with RPM and Torque as factors, not an actual measurement. Simply raising the RPM, given the same torque, will produce nght HP figures.

What most of us want is high torque, that measurable (and SOTP) factor that accelerates the car. Again, that torque is why I opted for the longer stroke, topped with a total package that will feed the appropriate air and fuel to this 'air pump', known as my 409 cid SBC.

 

[Nick90vetteguy]

thanks WhalePirot

SO how this all happened was I met someone that has a L98 but cammed it, and wow it sounds great, he said the type of cam he has is made for higher RPM. Like I said if I can just get that "choppy" sound id be thrilled, but if I can keep that low rpm range id be satisfied, So just to clarify, these perfomance cams are built through customers "wants" and "Needs" right? Which majority of them are high rpm cams and wont pass emissions. Now I have a high cat on my corvette, with long tube headers and eliminators, since I wont be changing the cam anytime soon, is there a way I can obtain that "choppy" sound through something else? If not can I get a cam/lifters for my L98?