What am I doing wrong? Why is my car not quicker than it is?

[HouTX87]

I thought the op might find this thread interesting.

http://www.turbobuick.com/forums/th...-seeking-10s-asap.400319/page-10#post-3321745

 

[10SECV6]

I have a feeling that my original cam has probably lost a bit of lift over the years. I don't think it has any flat lobes, but it probably not as crisp as it once was. I'm sure the car would run better with a fresh bump stick.

I purchased another T-type a few weeks ago that has a much fresher motor and trans in it that I could pull the motor out of and put in my black car and I'm seriously considering it. The motor has 13K miles on the build. It has a forged crank, ported heads, and a rather outrageous cam in it (not sure what pistons it has in it). I've had the valve covers and oil pan off the motor to replace gaskets and the motor is clean. The heads look to be very nicely ported and smooth from looking down the ports with the dog house off. I think the cam is a 218/218 flat tappet CompCams set up. It idles and sounds like a big cammed V8, but it's lazy down low, which I attribute to the cam. If I do it, I will stick more reasonable roller cam in it while it is out of the car.

 

[we4Mateo]

Well . . . This is my understanding . . .
Bigger tires will help, as will a cam . . . The flash stall is still too high, and bigger tires will lower rpm, resulting in increased slip on the big end. A cam will allow for higher rpm and better coupling, but . . It may also result in "driving through the converter". $ for $, Nothing will have the benefit of the proper converter.


Trying to learn here . . . .

I thought the slip would be the same with taller tires, but just bringing the engine back into its better operating range through lower gearing. And by loading the back side of the converter harder, lower gears or taller tires, doesn't that actually make the converter more efficient? It is my understanding that blowing through a converter only occurs when putting more power through the front side ie engine output. Since power is not changing, the load on the back side of the TC just needs to increase in order to make the front side and stator more efficient at pushing fluid through the backside resulting in more power to tires.

I may be understanding this incorrectly though. Please advise.

 

[HouTX87]

I have a feeling that my original cam has probably lost a bit of lift over the years. I don't think it has any flat lobes, but it probably not as crisp as it once was. I'm sure the car would run better with a fresh bump stick.

I purchased another T-type a few weeks ago that has a much fresher motor a trans in it that I could pull the motor out of and put in my black car and I'm seriously considering it. The motor has 13K miles on the build. It has a forged crank, ported heads, and a rather outrageous cam in it (not sure what pistons it has in it). I've had the valve covers and oil pan off the motor to replace gaskets and the motor is clean. The heads look to be very nicely ported and smooth from looking down the ports with the dog house off. I think the cam is a 218/218 flat tappet CompCams set up. It idles and sounds like a big cammed V8, but it's lazy down low, which I attribute to the cam. If I do it, I will stick more reasonable roller cam in it while it is out of the car.

I love seeing what these cars can do with stock long blocks, especially since that's my setup. Don't swap it yet.

 

[Jerryl]

I thought the slip would be the same with taller tires, but just bringing the engine back into its better operating range through lower gearing. And by loading the back side of the converter harder, lower gears or taller tires, doesn't that actually make the converter more efficient? It is my understanding that blowing through a converter only occurs when putting more power through the front side ie engine output. Since power is not changing, the load on the back side of the TC just needs to increase in order to make the front side and stator more efficient at pushing fluid through the backside resulting in more power to tires.

I may be understanding this incorrectly though. Please advise.

Nah, We are on the same page.
Was referring to more hp with cam change, possibly blowing through the converter.
A converter typicaly requires about 2400-2600 from 0/0 stall to couple. So if rpm drops, with larger tures, slip will increase. So a stock cammed car will have trouble getting max coupling with a higher stall converter.

Again, that's my understanding.

 

[gn4u2c]

I been 10.50 on stock longblock and 255/50/16 dr's , I see 2 real problems, 1 your driving over the converter or the trans has some slippage,
2 every car is different, try adding or taking timing out, try up and down on your target AF forget everything except your MPH 1/8 and 1/4 while tuning.
don't think your going to be sub 11.50 with that combo though

 

[we4Mateo]

Nah, We are on the same page.
Was referring to more hp with cam change, possibly blowing through the converter.
A converter typicaly requires about 2400-2600 from 0/0 stall to couple. So if rpm drops, with larger tures, slip will increase. So a stock cammed car will have trouble getting max coupling with a higher stall converter.

Again, that's my understanding.

Makes sense. My TC worked a lot better after the cam upgrade even unlocked.

 

[bison]

I thought the slip would be the same with taller tires, but just bringing the engine back into its better operating range through lower gearing. And by loading the back side of the converter harder, lower gears or taller tires, doesn't that actually make the converter more efficient? It is my understanding that blowing through a converter only occurs when putting more power through the front side ie engine output. Since power is not changing, the load on the back side of the TC just needs to increase in order to make the front side and stator more efficient at pushing fluid through the backside resulting in more power to tires.

I may be understanding this incorrectly though. Please advise.

The slip will be worse because driveshaft speed will be lower and the flash rpm the same

 

[V6RACER]

I've seen where timing chains were stretched or cam wasn't degreed correctly and you'll beat your head against the wall...

Also, timing could be off if interrupter ring is off...

Verify those two things bet you find something