A4's and 112's. Trying to clear things up.
 

(I know, I know.... another cam thread. Yes, I've read JRP's great writeup. ;) )

Two things I've noticed on various boards:

1st: I hear a lot of people say that if you're running an A4, that you should stick with a 114LSA.

2nd: I also see a fair amount of potential cam-buyers who are running A4's, asking if they can get away with stock tuning, or maybe even stock converters with a particular cam.

Are these two observations of mine related??

What I'm getting at, is... Is this 1st observation just a "general rule of thumb" that factors in the people who don't like to tune?

I understand LSA, where the more lobe seperation you have, the wider the effective powerband is..... and what we're really talking about is overlap. The less overlap, the wider the powerband. More overlap, more peaky but stronger powerband.

Am I correct in assuming a fast-ramping TR220 112 with about 270* of advertised duration, is going to have less overlap compared to something like an older B1 with 221* @ .050 and 284* adv. - EVEN with it on a 114?

It seems to me that 9 times out of 10 the B1 would get recommended over the TR220 - just because it's on a 114.

If all of my thinking is right - it seems that the "A4's need 114's" card should only be pulled if the durations are on the large side where idle may be bothersome either way, or we're talking about a lazy lobed cam in a daily driver. ...Right?

The only reason I'm nit-picking about all of this is because I'm really intrigued by this T1 vs B1 vs B1 dyno. T1 being in light blue.

If I can run a mild mannered 112LSA cam and walk away with what looks like 10-15 ft/lbs of some lower-end torque, then why not? Is there something else going on that I'm missing?

a 114 would just idle better in an a4 with stock tuning only because a4's are set to idle at 550 from the factory...put in a lopey cam and see that idle fluxuate from 400-1000rpms...go to ls1sounds.com and look up my byte borla 231/237 and heads you'll see how it idles on stock tuning. Once you get tuned I personally dont see a problem running any cam on a 112 with an auto.

I had a TR 224 112. I liked that cam.

i had the comp 224/224 .581 112 and it rocked in my A4... i did raise the idle with edit and minor tunning but with stock heads and bolt ons it went 11.78 :) and 10.735 with 150 TNT kit :)

i have a t1 in an auto. it ran well enough to get to mti (only a 20 minute drive) but i wouldn't want to drive it every day like that. the tune made all the difference. i idle at 950 out of gear, and 850 in gear.

How did you go 11.78? PM me your secret. I can't break out of the low 12's.

I run X1 cam on 112 lobe and love it. The sound is sweet and I had hell with idle until tuning. Runs perfect now!

A4's gear spacing is wide vs. M6s. Because of this, a wider powerband is usually a better match for an A4. BUT, factor in a hi stall TC, then a tighter lsa cam with the right duration to bring the power band up to match the TC's stall speed would become a better choice. (Actually you'd prferably want to match the converter to the cam) You wouldn't need the a wide powerband because the hi-stall would bypass the lower portion of the powerband. So, there is benefit in both wide & tight lsa for A4s depending upon the rest of the drivetrain setup.

This site might be worth checking out. It explains some cam basics w/ graphs: http://www.newcovenant.com/speedcraf...camshaft/6.htm

just to let you know the tr220 can be had on a 114 as well :). really what it comes down to is how competent your tuner is and matching the TC and gears rather then 112 vs 114.

but shit, what do i know, i drive an m6 :lol: :drive:

I had asked the same ?'s before, then decided it was time for a lumpy cam, TSP 231/237 .598/.595 @ 112* with the 3k stall feels nice all the way thru the range.

A cam idle characteristics and drivability is not solely based on its lsa. Valve events and ramp rates play a role in this too.
An XE-R cam VS a lower ramp rate would act more nervous, and would be harder to tame on a 112.
Check out the TSP 225 & 231 cams, they behave rather well on a 112 vs a Comp 224/112 XE-R in an A4

I have a 224/228 112 in an A4 and the only problem I have is once in a while it wants to die at a light. If that happens I just put it in neutral for a few seconds and it's fine. That doesn't happen much though. Also I did have it tuned a Speed so with out tuning I don't know how it would drive.

Yeah, that's what I kind of meant with the B1 example...


That's strange... I always assumed the faster the ramps, the easier it would be to tune and tame.

The main reason I'm asking all of this, is because I've got a TR220 112 coming at a good price. I just figured I'd give it a shot. If I don't like it much, I can move on...

Thanks for everyones replies so far, I appreciate it.

Another happy MTI X1 (112) user here. Works great with MTI mail order tuning.

Like others have said, it's all about the tuning.

You can run a 108 LSA in an A4 with the right tuning. I've had a 112 in mine for over a year with no problems at all.

I had a C1 hammer cam that was on a 112 with a stock head car.
With just a mail order tune it went 11.60 @ 115mph.Awesome cam!
Other then that it was just your basic bolt-ons and a 3200 Vig.

As stated by others, it comes down to tuning and if you go big stall converter and gearing.

Other than that all you need is enough vaccume to run your brakes.;)

Talk to a couple of tuners in your area and see what they have done.