Not a likely title for a Buick I know, but I am now able to mat it off the line and hook without spinning at the strip. This is a good thing right...yeah, until you discover this is still the weak link (60' times). This better traction is the result of the newly installed Mickey Thompson ET Streets. These tires helped improve my 60' times from 1.74 (old BFGoodrich drag radials) to 1.70's. I am happy with my 1/4 miles times but would like to improve the 60' times (pulling a tire would be nice too). Here's my best run this year at Bowling Green: 60' 1.696 330' 4.772 1/8 7.359 mph 95.18 1000' 9.619 1/4 11.540 mph 116.87 I think 1.696, is about all my combination will do, here are some contributing factors: Rear gear 3.42 Intake SP-1 3200 stall converter Only fair torque at 3200 2.48 first gear ratio Tires are 28" in diameter Stage 1 valves Race weight is 3900 lbs. On the chassis dyno, my peak torque is at 4600 rpm's (~430), and above 425 ft-lbs from 4550 to 5300. The torque is somewhat low at lower rpm's, for example; at 3200 its around 220, at 3500 its 250, at 3800 its 310 and at 4100 its 370. I know more torque off the line does not necessarily mean better 60' times, but I'll work on the suspension when that happens. What's the best way to improve my 60' times for this street car.......without changing my gear ratio or tires?
Converter change. You're probably thinking the same thing since you mentioned the torque at 3200. It would be the simplest thing to do, but not the least expensive. A good converter with minimal slip on the top end or during cruise (I assume you drive this on the street) is going to be expensive. I'd figure around a grand or so. With your dyno sheet a good converter shop will be able to dial one in pretty close to optimum. You could cover some of that also with a change to a 2.75 1st gear in the trans. Your racing weight is very close to mine (3885 lbs), my best 60' is 1.57 with the stock SP converter and the same tire, with more rear gear (4.33). I'm running through the lights at 6,300.
Assuming you have infinite traction, here are some things to consider: 1) Sounds like the torque converter might help - try to get in your torque band when you launch. 2) Actually I tried Rhodes lifters last year, and gained about 0.1 on my 60'. I know a lot of people don't like them but they worked for me. (Gained me about 0.2 & 2 MPH in the 1/4 mile, and added quite a bit of MPG/drivability). 3) TA aluminum heads are on sale right now. I know this sounds counter-intuitive, but if you go to a SMALLER cam, that will help low-end torque- and the aluminum heads will (more than) make up for the difference at the top of your RPM range. You'd have to work with TA to come up with a cam especially for this purpose... -Bob C.
Rear suspension is stock except for these exceptions: Air shocks, line is combined, I typically run 55 psi in them The rear lower control arms are boxed with sway bar All suspension bushings are from Energy (polyurethane). As mentioned I now hook off the line at the strip. My first thought was a lower 1st gear, but after talking to my transmission guy this is a expensive option. Next I thought about sending the PTC nitrous 10" converter back for modifications. It locks up nice with only about 6% slippage in the traps. PTC said they could modify it for about $75. I'm thinking maybe 3600 stall but don't know how much street manners would change.o No: This is where I need inputs. I do use a B&M (radiator style) heavy duty trans. cooler that measures 8.5" x 11". I do not run the lines through the radiator, but I do have the option.
I ran a 1.64 60' with a bone stock suspension set up and Hossier QT's. This was in basicly off idle with a Coan 4000 stall. My torque range basicly starts @ 4000.....so I'm looking forward to getting back to the track. Maybe a converter change would help or try getting up on it more.
I found launching at 3000 did not work as well as a 2000 rpm launch. The 2000 rpm launch I feel did a better job at flashing the converter, I may even try 1000 launch next time. How does a 4000 stall converter drive on the street? I know a 4000 or 4600 stall would be faster on the track but maybe too high on the street. It will be a compromise either way and that's expected. It's not too hilly around this part of NC so a little more stall may be the answer. The question is wheather to have my existing converter loosened or purchase a new custom converter. Anybody running a 3200 + stall converter from PTC?
Both Jim N and I use Coan's Max Perf 10" with 4000 stall. Absolutely no street driveability issues. It's like driving a stocker until you mash it!
Im far from very experienced, but heres what I found. My best 60 ft times came when I launched at 1000rpm. The further went up with the rpms the worse my times got. I have a 3000 stall tci street fighter converter. My best was a 1.69 but my top end is a 1/2 sec slower than yours. I do have adjustable upper controlarms that came set for a pinoin angle to give a better launch. Hoping to have a fuel delivery problem figured out to get me into the 11 sec club. Matt:beers2:
I'm not sure which cam you're running,but you can pick up some bottom end by advancing the cam some. Also,we picked up some 60' on the wifes X by going from a 28" tire to a 27" tire with the 3.42 and 3000 converter. gary
I'm already at 215 psi cranking compression so I don't want to advance the cam any more. I think a converter change or modification is my best choice right now. I could sell my PTC and buy a new converter or have my PTC modified. I paid ~450 for my 3200 10" nitrous converter.
You're right,I didn't know which cam you had. Try about a 3600+ converter.get good one that has less top end slippage. We have a SP in my sons car its 3800/1800 and he 60's in the 1.64's
I do have corrected times (from diffrent days/\tracks) but I've made several changes at once.....so I can't say. I do know that when I make runs back to back, it does not slow up, it typically picks up a little. The cooler outside air has a bigger benefit than the ram effect, but both are nice.
4000 stall as the others ahead of me posted and i get my best 60' form mashing it @ 1400 but i am running ladder bars.I do find it harder to cut a light opposed to loading the converter. Jamie
Is it a sign when you search for information on something and you find a post you made years ago? It's obviously a sign to get off my butt and get something done! Anyways...I went out this last weekend, slid under the Buick and took some rear suspension measurements. Here's what I found, and potentially why I am not hooking as well as I want. Drive shaft angle - .68 deg. up in front Lower link - 1.85 deg. up in front Upper link - 3.60 deg. up in front I was trying to find the Instant Center, but as it stands the projected line towards the front of the lower and upper links do not intersect See, my best friend is building a Chevelle ("rustbucket") to beat my Buick. Bad part is, he has the motor and know how and he knows how fast my car is. I figure my best bet is to optimize my 60' without him knowing and catch him on his maiden track voyage. Rear Details: I can not floor it right away I must ease it down....wasting some time. I do not have any wheel hop issues. New tires are in my future, old MT are about warn out, they are about 3 yrs. old I know a higher quality stall converter would help, but hay if I can't floor it now anyway... Rear shocks are air shocks not ideal I do not want to lower ride height much because of header to ground clearance is already at a minimum Polyurethane bushings throughout on rear Boxed lower links Sway bar Some exhaust clearance issue with upper link on one side, required some link trimming. 10 bold rear with bolted axles, 3.42 posi Thinking: upper adjustable, air bag in right rear and maybe no hop bars? Hey, it's good to be back!
Did you ever look at your front suspension ?? Like a drag shock or removing front sway bar if you have one?? The quicker the car can get up and out the faster it will be..
I disconnected the sway bar once at the track but did not see a difference o No: Here is a diagram showing the upper and lower link angles. Notice they do not cross, but the rear is not really up that high. The top wheel lip at the rear is 26 3/4" from the floor.
