How much hp is a slightly ported 1pc intake good for

[Vigo]

Funny thing is Vigo just last week I was remembering that thread that part number ID'd the different cam gears and the amount of timing change that is built into each gear. I was thinking of asking if anyone remembered what thread that was in, was it 4Lbodies (Todd N's thread?) My daughters TBI LeBaron needs a little more grunt to get out into traffic and I'm thinking a little advance would help, I doubt the motor will ever see more than 4500RPMS so I think there would be no trade off shifting the power curve to the left.

I remember the thread but now how to find it. I do remember your help in '09, still appreciated! I agree there would be no downside to a little cam advance. On my old 5spd tbis (both my aries and crapbox caravan were run for years as 5spd tbis before turboing) i shifted it at 4800-5200 anyway. Shifting the powerband 300-500 rpm to the left does not seem like a big enough change to cause any major side effects.

[mopar-tech]

https://youtu.be/JT2pWh92yBc

First time available- All the runs of the Daytona from its first at Cecil till it ran 12.6 at New England Dragway and the video ends with a few minutes of the Daytona on the dyno. My notes (and webpage I put up for the club years ago) indicate it was NOT running full boost but 22-23 psi. One of the club members even indicates this by flashing "22" with his fingers during a pull. 254hp and 321 ft/lbs torque

http://www.thedodgegarage.com/ne_sdac_dyno_day.html

Enjoy

Gary

[GLHS60]

Funny thing is Vigo just last week I was remembering that thread that part number ID'd the different cam gears and the amount of timing change that is built into each gear. I was thinking of asking if anyone remembered what thread that was in, was it 4Lbodies (Todd N's thread?) My daughters TBI LeBaron needs a little more grunt to get out into traffic and I'm thinking a little advance would help, I doubt the motor will ever see more than 4500RPMS so I think there would be no trade off shifting the power curve to the left.

Some TBI folks advance a full tooth and have good results.

Cheap, easy and reversible!!

Thanks
Randy

[mopar-tech]

Great info as usual Gary!!

Thanks
Randy

Just wanted to follow up on this as I might have been under caffeinated when posting...

Cam timing is one of those subjects that can get a raging debate going among engine builders. Some argue that its best to make peak power on the dyno and then drop the engine in the car and seal the hood! I'm from the school of thought that you have to work with the track and chassis you have to some degree so that requires you to adjust engine output as needed to maximize the cars ability to make it down the track as quickly as possible. If that means adjusting the engine's output to suit the track, then so be it. I'm in it to win behind the wheel, not on a dyno.

Ask the Supra owner.

That being said my advice would be... Do not get hung up on the advertised centerline of the camshaft. Someone picked the number based on a priority that might not even be germane to our usage. It might have been some sweet spot for emissions, a corporate suit mandated hp target dictated by focus groups or some engineers pet theory. Its a good starting point for tuning, nothing more.

When I was street racing the GTX... way back in the late 80's I discovered the wonders of cam centerlining and the effects of rolling the timing from as low as 106 to 114. One would give me buckets of torque that would blow the tires away.. and the other end of the range would make the car soggy down low but have a hell of a top end charge. The trick is to find that sweet spot with just enough torque to keep the tires from getting blown away on the bottom end of the track while having enough juice for the top end charge.

Hope this dusty recollection is of some value to you.

Gary

[glhs875]

I feel that a well designed camshaft advance/retard system would be very beneficial on our combos!

[mopar-tech]

I feel that a well designed camshaft advance/retard system would be very beneficial on our combos!

I have given that some great thought over a period of years.

In some cases it MIGHT be of some benefit. The SOHC turbo engines are already naturally torquey so would not benefit as much compared to a smaller displacement N/A engine or if the engine is installed in a heavy vehicle. My 3.6 Challenger is a perfect example of a heavy vehicle with a small displacement engine, it does very well.

When you can "come out of the hole" under boost it almost makes variable cam timing irrelevant of everything is sized properly..

[2.216VTurbo]

Where's RGL10(or whatever his goofy screename is) in this cam timing discussion? AFAIK he's the only one adjusting his cam timing on the fly...

[glhs875]

I have given that some great thought over a period of years.

In some cases it MIGHT be of some benefit. The SOHC turbo engines are already naturally torquey so would not benefit as much compared to a smaller displacement N/A engine or if the engine is installed in a heavy vehicle. My 3.6 Challenger is a perfect example of a heavy vehicle with a small displacement engine, it does very well.

When you can "come out of the hole" under boost it almost makes variable cam timing irrelevant of everything is sized properly..

Everyone has their own opinion! I know that I would like variable cam timing! Even if you don't really see a benefit I do! Difference of opinion keeps the world from being boring!

[GLHS60]

RGL variable cam timing.

Thanks
Randy

https://youtu.be/GkmyXnIMjC8

[GLHS60]

Where's RGL10(or whatever his goofy screename is) in this cam timing discussion? AFAIK he's the only one adjusting his cam timing on the fly...

Alan, some of us don't think Randy is a goofy name, a girls name but not goofy!!!

Thanks
RANDY

[GLHS60]

Just wanted to follow up on this as I might have been under caffeinated when posting...

Cam timing is one of those subjects that can get a raging debate going among engine builders. Some argue that its best to make peak power on the dyno and then drop the engine in the car and seal the hood! I'm from the school of thought that you have to work with the track and chassis you have to some degree so that requires you to adjust engine output as needed to maximize the cars ability to make it down the track as quickly as possible. If that means adjusting the engine's output to suit the track, then so be it. I'm in it to win behind the wheel, not on a dyno.

Ask the Supra owner.

That being said my advice would be... Do not get hung up on the advertised centerline of the camshaft. Someone picked the number based on a priority that might not even be germane to our usage. It might have been some sweet spot for emissions, a corporate suit mandated hp target dictated by focus groups or some engineers pet theory. Its a good starting point for tuning, nothing more.

When I was street racing the GTX... way back in the late 80's I discovered the wonders of cam centerlining and the effects of rolling the timing from as low as 106 to 114. One would give me buckets of torque that would blow the tires away.. and the other end of the range would make the car soggy down low but have a hell of a top end charge. The trick is to find that sweet spot with just enough torque to keep the tires from getting blown away on the bottom end of the track while having enough juice for the top end charge.

Hope this dusty recollection is of some value to you.

Gary

Everything you say is of value!!

You are always correct and respected for sharing your vast experience.

Have to give Randy, RGL10, credit for building so much technology into his Omni without spending a lot of loot.

Might not be highly beneficial but certainly highly skilled construction and educational.

Thanks
Randy

[GLHS60]

I feel that a well designed camshaft advance/retard system would be very beneficial on our combos!

RGL build thread, Randy certainly has talent!!!!

Thanks
Randy

http://www.turbo-mopar.com/forums/sh...-testbed-build

[mopar-tech]

You are always correct and respected for sharing your vast experience.

Thank you for the kind words but not always correct as I'm only human and only good as the data that has been provided.

There was much that had to be "unlearned" when I started out and there are always new things to be learned.

[MILKCARTON]

Did you lighten the hatch any?

the hatch is a single wall dzused on deck lid now, back window is Lexan

[MILKCARTON]

I was only using 2 degrees as an example LOL! I run more than that on my combos as well!

- - - Updated - - -



Impressive! Put it on a dyno so we can see what is going on! BTW what's the turbo?

I might here soon, I have to fix a cracked flex plate first, 50 trim from FWD that I got in a trade years ago

[glhs875]

the hatch is a single wall dzused on deck lid now, back window is Lexan

Interested! Any pictures? BTW I was stationed at Ft Carson in the Early/mid '80's! Love the area!

[MILKCARTON]

Interested! Any pictures? BTW I was stationed at Ft Carson in the Early/mid '80's! Love the area!

I like it here too, I work on Carson, just don't love the altitude...

[glhs875]

I might here soon, I have to fix a cracked flex plate first, 50 trim from FWD that I got in a trade years ago

Your car would EASILY run in the 6's at a lower altitude!

[tryingbe]

Off topic, open your own thread.

14 pound per square inch is the same everywhere, even in vacuum of space.
However, the atmospheric pressure (ATM) can change due to weather and elevation. ATM affects all combustion based engines.

[mopar-tech]

I'm guilty of the stray off topic, sorry! BTW maybe you should start a thread on the topic. There is proof blasted all over the net that elevation does effect turbocharged and supercharged vehicles!

Effect yes, as much as a normally aspirated engine? No.

There are no shortage of calculators on the internet that will spell out just how much power a N/A engine will lose based on a given altitude.

A turbocharged engine will simply spin the turbo a touch harder to maintain the desired pressure in the intact tract.

For example- If you take a 150 hp N/A engine and climb 5000 ft the engine will lose 18% of its rated HP or in this case 27 hp due to the change in air density.

Will a similar engine with a turbocharger rated for 150 hp lose 18%? Nope.

This is basic stuff, plastered all over the internet. Try looking up aircraft engine ratings for a given altitude for starters.