07 GT automatic: 1/4 mile ET improvements after various mods...

[US-1]

It will allow you to get more than 11.90's. And honestly...I wouldn't do anything else until you get the headers installed. It has to breathe. Period. Especially if you want the stock shortblock to live any length of time.

 

[don_w]

Thread moved to drag racing forum...

 

[Five Oh Brian]

It will allow you to get more than 11.90's. And honestly...I wouldn't do anything else until you get the headers installed. It has to breathe. Period. Especially if you want the stock shortblock to live any length of time.

True; headers would likely lower the boost I'm seeing, while increasing power. Lower boost would go a long way to keeping the stock shortblock intact.

 

[Peaky85]

I see no mention of suspension mods ... have you installed any ? You could see some good benefits with the standards ... Lower Control Arms, LCA Relocation Brackets and an Adjustable Upper Control Arm. From one Alloy to another, good luck !

 

[Five Oh Brian]

I see no mention of suspension mods ... have you installed any ? You could see some good benefits with the standards ... Lower Control Arms, LCA Relocation Brackets and an Adjustable Upper Control Arm. From one Alloy to another, good luck !

Thanks, my Alloy friend! My GT is still sporting 100% factory suspension. It dead hooks at the strip launching at 4800 rpm's and there is zero wheel hop, so I don't feel I need to change anything yet. A lot of S197's with manual transmissions hop like crazy, so I can see why LCA's and UCA's are so popular for them, but I'm not making enough power to need them (yet). At some point, I'll be making enough power to warrant them, but until then.....

 

[Vashthe3rd]

After/Inter cooler
Headers
Meth kit
Control arms
any of these could give you that bump to 11's.
What kind of fuel system are you using? Pump, injectors?
More power/better times are within your grasp you just need a little cooling.

 

[Five Oh Brian]

After/Inter cooler
Headers
Meth kit
Control arms
any of these could give you that bump to 11's.
What kind of fuel system are you using? Pump, injectors?
More power/better times are within your grasp you just need a little cooling.

You are correct; some cooling would allow me to really turn up the wick. I'm 90% certain I'll go with water/meth injection instead of the aftercooler for my Vortech blower. I'm currently running 39# injectors with 2 fuel pumps. The guy that did my custom dyno tuning says I'm nowhere close to running out of fuel, so the current fuel system should be enough for the modest bump in power I'll be looking to accomplish. My goal is to get the car into the high 11's and then stop modding. It's a daily driver, so I don't want to install a cage, therefor I'll be happy with high 11's.

 

[sixshooter798]

I have no idea how much horsepower headers add, but I installed headers and pullies and dropped 3 tenths.

 

[808muscle]

Headers FiveOh!!!

Headers, Headers Headers!!! LOL


The tone, the better breathing, the 11 second timeslips!!! LOL

patrick

 

[Five Oh Brian]

You guys are so right. Headers are on my short list of goodies to add....

1. Headers. 2. Water/Meth Injection. 3. Blower Cams.

 

[Five Oh Brian]

For those who like vids, here's a couple vids from inside my GT taken at Bremerton Raceways right after my blower first went on 2 years ago. The purple '70 Olds Cutlass I ran against in the first one was a trailered-in car on slicks running low 12's all day. The white '66 Mustang in the second vid really impressed me - super clean street car that I thought was gonna run 14's, yet he was pulling mid 12's....

 

[topbliss]

good vid Brian..... You car really runs nice. The headers will help a lot.. I agree with everyone.. How is the trans holding up? No slippage???

 

[BlownAway05]

If I were in your shoes, I'd do either the aftercooler or meth, and out of those 2, seems you'd rather do meth. Just my two pennies.

 

[Five Oh Brian]

good vid Brian..... You car really runs nice. The headers will help a lot.. I agree with everyone.. How is the trans holding up? No slippage???

Thanks. The trans is holding up well, but I'm changing the fluid regularly to keep it alive. And someday when the trans lets go, I'll order up a built one (i.e. Level 10, TCI, etc.).

I gotta save up for those headers. I just spent over a grand on brakes (slotted rotors, ceramic pads, SLP line lock, etc.) last week, so I'm back to square one saving up for go-fast stuff.

 

[Five Oh Brian]

If I were in your shoes, I'd do either the aftercooler or meth, and out of those 2, seems you'd rather do meth. Just my two pennies.

The aftercooler would be nice (perhaps the Paxton air-to-air), but costs way more than the meth. Plus, the meth not only cools IAT's, but creates more octane. So, less expensive and more potential power gains. I have to do something to keep the IAT's in check, though.

 

[bluebloodbundy]

I would look more into doing an IC and stay away from the meth on a stock block.There are far more variables with the meth and with the stock rods/pistons there is very little room for error. Step 2 would be headers and then start saving for a built bottom end so you can turn it up and really have some fun.

 

[Five Oh Brian]

Just wanted to recap and update this thread as I made a few more changes to the car and got back to the local tracks to see what worked. So, from the beginning until now, here we go again.....


I never ran my car at the track bone stock, but most 05-09 GT automatic coupes tend to average 13.9's @ 99 mph in the 1/4 mile (give or take a little).

My first mod was 4.10 gears, which required a handheld tuner to correct the speedometer. So, I set that tuner (DiabloSport Predator) to their canned 92 octane tune and ran 13.4's @ 102+ on the factory tires.

The next mod was a bigger stall converter (from Fuddle Racing). It flashed to 3,800 rpm's so the launch was much better, but tough on the stock tires (I really cooked the stock tires before lining up to melt them into submission). Car was running 13.2's @ 103+ when I could get traction. 60' times improved dramatically with the converter (1.8's vs 2.1's with the factory converter).

Drag radials made staging and launching easier and the runs got very consistent: 13.1's @ 103+.

Vortech V2 S-trim supercharger (non-intercooled) took some learning and tuning, and the stall converter now flashes to 4,800 rpm's with the extra power, but conservatively dyno tuned (daily driver) it intially ran 12.6's @ 110+

Swapped spark plugs for colder/copper FRPP 3V0 spark plugs, plus I added an oil seperator and PCV valve to keep oil vapor out of the intake tract. Had more dyno tuning done to adjust shift points & firmness, converter lock-up, etc. Car ran 12.3's @ 111+

Replaced the factory catalytic converters and H-pipe with an SLP X-pipe with high flow cats. Car ran 12.1's @ 113+.

Replaced the factory coil on plugs (20K volts) with GMS "hot street" coils (45K volts) and removed the front sway bar. Car now runs 11.8's @ 114+.

 

[TheDarkPath]

Nice run and congrats getting into the 11s! What was your 60' time?
I can't help but think your 60' should be better than what you posted before (1.8s) for a stalled/blown auto. I'm hoping after an issue with the rear axle alignment was fixed, the vibration issues I was having with my driveshaft will be cured. With that, the off-road H, and some practice, I'm hoping for some 12.2s in the right weather. Will be doing a stall early next year and hoping for 11s!

 

[Five Oh Brian]

Nice run and congrats getting into the 11s! What was your 60' time?
I can't help but think your 60' should be better than what you posted before (1.8s) for a stalled/blown auto. I'm hoping after an issue with the rear axle alignment was fixed, the vibration issues I was having with my driveshaft will be cured. With that, the off-road H, and some practice, I'm hoping for some 12.2s in the right weather. Will be doing a stall early next year and hoping for 11s!

Thanks! You are correct about my 60' times. My 11.79 run was on a 1.66 sixty foot. Same day I ran 1.6's and low 1.7's. The stall converter is a must with our automatics to launch well.