348 throttle body porting

we're all gear heads here, and so know that the joy of this hobby is working on our cars, Ferrari or our first car owned.....and is why it's such fun to read Ernie's or Plugzits (and others) threads on thier own projects

this is but one mod in a series as you say.....even recently guru Mr Helms stated that he doesn't see big single gains, it's all an accumulation of little improvements

thanks to you guys for continuing to post these up

 

C5 Z06 was rated 405hp. There are plenty of dyno graphs of stock C5 z06's showing 360-370rwhp.

Are there any aftermarket cams available for the 348?

 

Not the 2001, it was 385 crank hp.
It also had magnesium wheels.

 

Rob,

That is a very respectable number and totally believable. Dyno's vary and vary more with air correction factors and all kinds of other stuff that I can't remember. Additionally, all this talk about HP and torque is a waste to me because the real deal is area under the curve. The LS2/3 C6 chassis in T1 clubracing is totally dominant vs. the C5z06 LS6 even with the extra 300lbs it has to carry per the rules! The LS2/3/6 built to rules all put out similar HP/torque. Its the area under the curves that really speak to useable HP/torque that make the C6 chassis a class killer in SCCA.

 

Not yet, been kinda busy, but high on my list!

 

+1

yes part throttle does matter as well as the shape of the power curve but you wont get much respect here on fchat with it! you can have good peak numbers on a dyno and the car could be vastly slower on the track.

every single dyno is different. much more useful to run a baseline figure and see what improvements you get from there from the same dyno. unless you want bragging rights on the net. makes no sense to compare a inertia dyno (early dynojet) to a much more useful load bearing type.

not to rain on ernies parade but if there is a 22% improvement through the TB does that equal 22% more power? i only wish it was that easy!

still very interested in how this all pans out...

best of luck

rs

 

What have you done to your car so far in total? High flow cats, better exhaust, right? Did you dyno stock and then dyno after the mods so far? Just trying to figure out where you're at. I like this kind of project but sometimes it's tough to get the full picture.

 

I finally read this list - pretty good and just about everything goth and I did. Don't forget the KN air filter which you probably already have. Then you need some chips. After that, I'd spend more time trying to get more performance out of weigh savings - AC removal, smaller battery, strip the interior, removal of non-essential items and equipment, replace seats with light weight racing shells. You have about 200-300 lbs to spare in that crate.

 

Interesting...
And so far the dyno reading is?

 

E,

I got smart phone HP aps, G-tech meter and very accurate AIM solo. We can figure out the HP if your car drives and has a place to plug a cigarette lighter adapter for free! What are you doing sunday?

 

so question... I am all for porting and smoothing. But how does this change the reliability when you start adding/doing these type of things? sorry for the ignorant question.

 

good point on opening it up a just a few mm’s. there are advantages of keeping the TB no bigger than you need. Basically find out your targeted output of the motor you want then size the TB accordingly much like what a venturi's do on weber carbs or restrictor plate limiting the power on a series race car. Going to a much bigger will affect your part throttle response and velocity, reducing the inertia of the intake charge filling lowering the bmep.

my hunch, and its just that, looking at latest cylinder heads, the intake valves, and bowl area are much larger on the newer cars than say performance heads of just 10-15 years ago. A good place to start would be the valve throat area coupled with larger intake valves if there is room. i reckon most of the gains are there when combine with more CR and cam. Once you determine the flow rate of the head assembly then size the TB. From there tackle the headers desired length/diameter to suit characteristics of your motor, plenum size/intake tract, airbox, corrugated tube etc.

my 2 cents

hf

hf

 

It's not the 348 but I have some results from the TBs on my 300ZX.

The peak gains for HP and TQ were 6 and 7 respectively, right where I expected on a stock car, higher gains will certainly be realized with a car with aftermarket turbos/etc.

The area under the curve is what really surprised me (though it makes sense now that I think about it). Let's pick 2900 RPM for the comparison, right in the RPM range that you will see often in normal driving. Stock 50mm TBs produced 176 RWTQ and 98 RWHP. 54mm TBs made 252 RWTQ and 136 RWHP.


Hurry up and find some stock TBs Ernie, I want to see what the difference is on your car.


Rob

 

i depends on how accurately you want to record gains from each mod.....the most accurate is to have all OEM stock except one mod, then return to stock & another mods....giving a record of what each mod gains independantly

IMO iff you are going stock OEM for a baseline, do the intake mods first on dyno, then exhaust after....i think you'll find that the freed up exhaust will reduce the "apparent" gains of the intake mods

 

I feel this increase would hold it's advantage farther up the rev range on an NA engine.

Rob
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At this point I would just test as is. Us a cheap phone ap and see if the changes warrant spending money on real dyno time. We all know a 348 motor is somewhere around 300hp and numberous people have posted their stock RWHP which I can't remember. Lets hope for +20-30hp out of your mods which will remove all doubt. Did you rewire too? proper stock combustion is a necessary starting point.