JeremiahsC5

Been a weekend drag off and on for the last few years. I am currently running a boosted C5 with auto tranny and 3.73 gears. I am putting down 560hp to the rear wheels and 480tq. In the past always run with front end links off but the rest pretty much stock. I was wondering what people would recomend for the next step. Also running CCW drag pack.

REDGAR

Adjustable shocks might be next.

They will help to fine tune the launches.
I run QA1 single adjustable that have been rebuilt specifically for drag racing.

You have a lot of options, none really cheap.
Phfadt has a lot of suspension parts available run by several guys on here, not me, yet

JeremiahsC5

Just bought a set of double adjustable QA1 shocks for the front. Are the rears something you would recomend getting as well.

REDGAR

To get the most out of the adjustability you want the rears as well. If you can only get the fronts now it is a start and you can complete the set at a later time

JeremiahsC5

At my horsepower level. Will a 28" tall tire hurt or help over a 26" tire.?

REDGAR

I have been running 28" for a long time now. Consistency and repeatability are very important to me and I feel "safer" having that chance with the 28". My car also leaves very hard and can leave with high 1.3 short times so I just want the extra height. I could probably make the 26" work but don't want the risk.

As for hurt you help you, depends on goal. I think the 28" will help you be consistent.

JeremiahsC5

Is it a good idea to firm up the rear spring. Do you want the rear end to be soft or hard fro good launches?

DBN

Redgar is leading you in the right direction. The double adjustable QA1s for the front are the most essential piece needed for your suspension. The rears are also important, but not as critical as the fronts. Go with the 28" tire if you are having a problem spinning off the line. This will also change your gear ratio so the combination of gear and tire will determine what rpm you are going through the traps at. Some cars need to stiffen the rear springs and some need a lighter rear spring. This depends on alot of variables. I would not be too quick to change the rear springs. I ran mid 1.3 60' times with a totally stock suspension with the addition of the QA1 shocks and CCW drag pack. Good luck.

JeremiahsC5

Glad to hear I am headed in the right direction. I have installed the new QA1 double adjustables on the front. Last time at the track I had ther rear spring stiffened up but ran the same 1.57 60'. I was a running a 28" tall tire as well. I have 3.73 gears just to add to info. The car was running 6.97 in the 1/8 and it has run as low as 6.68. I did a plug change and found that the #7 spark plug boot was just setting on the tip of the plug and arching inside. I also found that the number 8 plug was not white like the rest and had some oil on it. So not only am I dealing with trying to get the car setup better, I am trying to find out why I am running slower. I have new plugs and replaced the bad wire and I am going to soften the spring up for the drag strip tomorrow. hope my 60's are better tomorrow. Thanks for all the advice.

DBN

Anytime. Glad to help. You might want to do a leakdown test on #8 cylinder to see if you have lost a significant amount of compression. The oil is coming from somewhere.

JeremiahsC5

Did hour trip today to get some exhaust work done. Checked the plugs tonite and they seem to be fine. Not sure if I just had a bad plug or fouled it out. Will check tomorrow after a few passes. Softend up the spring tonite and going to see if it works better than the tight spring did. What PSI do you have the best luck with on the 28" tires? Always ran 13lbs in the 26" tires.

DBN

15 psi usually.

thechosenone

How much power are you making and whats your set-up?

mAydAy121

Jeremiah, I always get oil in #7 and #8 from the PCV system, especially as my catch can fills. The velocity of the oil mist being carried by the air coming into the intake manifold carries it to the back of the manifold, where it smashes into the back then gets sucked into the #7 and #8 runners.

JeremiahsC5

Thanks for the info on the plugs. I had another so so day at the track. Still running right at 7.0 at 100 mph. Had a horrible 161 60ft. I could not soften the suspension up because the 28 x 12.5 tires would hit the fenders. I did find when I got home that the old procharger bypass valve is leaking real bad. I think that where my boost issue was comming from. Was getting 8.5 pounds of boost and suposed to be getting 10. Anyone have any advice on which bypass valve to buy?