Aamer Sattar

I was hoping I could get Texas Speed Jason's ideas/help on this.
I've installed Texas Speed prc 227 heads and their 224 228 112 lsa cam
On a 2000 C5 automatic, with stock everything except a Cai.
I have a basic tune in place with the ve and maf dialed in based on ltft. (wideband on its way).
The combo has lost a lot of lowdown power. And has mediocre part throttle everywhere regardless of gear. Wot it goes like a demon.
It even has completely dead spots, for example 1200 to 1500 rpm in 4th 20 or 25% throttle, its dead, engine tone changes but tpms hardly do. A sharp jab of the throttle and it dowshits and does its mediocre acceleration

From the corvette forum many knowledgeable people have suggested that this is too much head for the cam and intake/exhaust combo, and I'd have to resort to changing those or change gearing.

Thing is, Texas speed, knows their stuff. I'd explained I'm running stock everything and this combo is what was supposed to give me decent power all round without losing much down low.

I need to know whether that really is the case and its just a matter of tuning, , or whether im going to have to change heads/cam.

Because of regulations, I can't add headers.

What I see is reduced airflow all round {till around 4000 after which there's no change}in the VE tables compared to stock after adjustments done based on ltft.
Same for the MAF calibrations, a bunch of minuses in the early frequencies and no plusses.
I would have expected a little bit of minus followed by a lot of plus.

I was hoping that Jason you may be able to castsome light on this. Is this a bad combo for my otherwise stock set up?
Regards
Aamer


andI've posted this on the corvette forum and got lots of knowledgeable opinions suggesting mostly that the combo would need intake, exhaust, perhaps TC and diff to work properly, and also others suggesting that it should work and it may be a cam degree ING issue or purely tuning.

madmann26

Two words.

Port velocity.

98CayenneT/A

At the very least I would run at least a 3000 stall converter.

showdog75

iTrader: (8)

Dead spots would be in the tune most likely. If TSP said it'll work my guess is it'll work and work well just need to sort it out. Call TSP.

Old Geezer

iTrader: (3)

Heads, cam, then "plug it up" with a mediocre exhaust?

Stampede4ever

Who is doing the tuning? And you say you are on a "Base" Tune, correct?

Stampede.

RonSSNova

iTrader: (3)

Aamer,

I posted in your other thread.
Dead in 4th as you described is likely because the torque converter is locked.
Stock tune locks it early.
It also locks in third gear.
Did your tuner adjust that?

Can you post the tune?

I also have a 2000 coupe A4.

Ron

wannafbody

iTrader: (2)

I have TSP ported 243 which are 225cc and it pulls like a freight train with a slightly larger BTR stage 2 cam with a M6. I'm guessing it's tune or tranny related. Also check your throttle cable to make sure it doesn't have too much slack in it.

Darth_V8r

iTrader: (4)

First gut instinct I got was the cam timing is off. Sounds like it is retarded quite a bit.

You never indicated your compression either. With that cam if you are not 11:1 or higher, it will be a turd.

If you have not tuned it yet, start there. Might be too rich down low making it act funny. But that is a pretty small cam. Should run fine down low.

RedXray

I agree with the above.

I have a similar setup prc heads camshaft in a heavier rcsb truck. Along with a tbss intake & 92mm tb, headers, converter & gears. Truck has nice part throttle power from a stop, rolling into the throttle after the 2nd shift the tires can brake loose without trying. Stomp the throttle from a stop it's a hand full with tire spin through 1st & 2nd. Hwy speed cruising around 2000 it needs the kick down to get the RPM's up in the powerband then it pulls hard to 7,000 RPM. I used the Bluecat software to tweak the transmission shift schedule which helps a lot. Does what I expected for a N/A 6.0 build.

SoCalDave

Your tune is off. Torque management needs to be off.

NAVYBLUE210

SWAP the 2.73s for 3.42s,
ADD 2800-3200 TC
AFTER
Verifying Correct Cam Install & Proper Tune!
(Stealth & Ported FAST 92/LS2 Tb or /LS6 Intake will help also)

Heads and cam are NOT too big with appropriate supporting mods and tune.

3.42s with Overdrive will still yield easy cruising 80-140 kmh.

It will drive & feel like a completely different animal when you put your foot in it,
and still drive very well at low speeds & cruising.

Just my .02

RonSSNova

iTrader: (3)

He is auto trans with a stock torque converter. Stalls at maybe 1800 rpm.
2.73 gears.
Whole different animal than a 6 speed.

C5 Corvettes are drive by wire.

stockA4

I yes if you insist on keeping the stock torque converter and 2.73 gears, the best heads for sub 4000rpm response would have to be the 706/862

wannafbody

iTrader: (2)

Well, 273 gears suck regardless of the rest of the combo.

zzracer

iTrader: (33)

He needs more gear and at least a 3600 stall. Converter is most of his problem. I see this all the time ,most people are scared to stall their cars.

stockA4

I have 2.73 gears and the stock torque converter still on one of my setups 226/230 112 + 4, 706 heads on an LQ4 and the stock tires 245/50r16 are useless in first gear. It will burn them from a stop starting in second most of the time too, it's also in an otherwise stock Camaro with a trunk full of s*** so it's heavier than a Corvette, I still have very much of the stock shift programming but tweaked a little with torque management still mostly enabled, You know it's got the stock original transmission and rear end with over 200,000 miles on it, the torque converter locks in third and fourth as it should as low as possibility around 1, 100 RPM and pulls really hard from there.

Darth_V8r

iTrader: (4)

Stock cam
Benefits from some stall yea?

zzracer

iTrader: (33)

Your engine makes a lot more torque than his because of the compression and cubic inches. You have enough power to break the tires loose easier and when you have higher gears and the power to start it spinning it will spin longer than if it was geared lower. I know that may sound crazy to some but that's how it works.
A heavier car with more torque will also loosen the converter up.

zzracer

iTrader: (33)

Absolutely!