fasteddi

iTrader: (2)

Yes im still running my turboed car at the track. It has had a few problems here and there but I figured that would happend with so many new mods.

Car is very consistant though. Its just inconsistant day to day. But if I trial then 3 hrs later run, its dot on no matter then weather. I think the alky injection helps this alot.

The fastest as of this year is a 13.36@102mph on slicks that are taller then the street tires. Now I've been tuning as much as I can and haven't gotten to the track in about 3 weeks and now I have a crap injector getting replaced so I am thinking of what she may do now that I turned up the boost and have the fueling for it, once I put the top end back on.

Stats: A datalog from the track on street tires shows a 0-100mph time of 14.20 when I made a 14.05@98mph pass at the race track. Yesterday I made a 0-100mph pull on the same tires in 12.09 seconds on the road. I know its not all about speed but am curious. Another time 0-110mph in 14.95 seconds on that same datalog. The g-tech said numbers that I just dont believe. 13.58@107Mph. I haven't liked the g-tech yet as its usually slower for the Et but somewhat close on the MPH.

Heres the thing, I see many people pushing 107mph+ at the race track to get into the 12's Why is it that I am trapping lower MPH (lets use the 102mph@13.36 seconds for example) Makes me wounder how much faster trap speeds I would need to get into the 12's. I have 3.23 gears in the rear. This is a boosted car, I would think that I would trap higher then other N/A cars running the same time with somewhat same gearing, weight, tires....

AlkyIROC

ET/MPH will vary considerably depending on each car's combination of parts. For a good 1/4 mile drag race car, the car should be topped out as it crosses the finish line. Only then can ET and MPH be used as a comparison. Typically a turbo car will MPH more than a NA running the same ET.

Many, many years ago, my gearing/tire combination was way off when I was running a 383. I ran 12.0 at 117 mph. The car was just starting to get into it's powerband around the 1000' mark and really started to pull while other cars running the same ET were topping out. A gear change was able to drop the time into the low 11's which better suited the MPH.

If you're still making more power as you cross the finish line, the car isn't set up to maximize performance. You should be reaching your maximum shift point while in high gear (not OD) at or just before the finish line.

project89

iTrader: (1)

he needs more gear for sure.

big part of ur problem fast is the launch ur waiting till down track to make power

heres a good example
one of my old runs 13.4 @101 i launched with a 1.94 60 about 3 psi of boost
next pass same tune and everything got about 5 psi on the line and went 1.8 60
the turbo came up on full boost much sooner leaving at the 5 psi instead of 3
the result was .400 and 3.5 mph cause the car was making more power off the line the second run


u still need to do a posi unit and a set of 3:42 gears, and ur car is going to pick up once u install those headers

what rpm are u crossing the stripe at iirc at 118mph with my 4:10's it was somthing like 7,300 rpms which is a few hundred rpm below redline on my car

in ur car u want to be turning about 6,200-6,500 as u cross the line

fasteddi

iTrader: (2)

It crosses the line at 5200 rpms(dataloggs say 105mph when the trap was 102 at the strip) which is under its full potential for power. Basically with that turbo it just pulls as long as it can(rpm wise) The otherday, 123mph on a closed crk road @ 5950rpms 3rd gear.

How would you find out how Rpms would raise up if all that was changed was the gear ratio.? Thanks

117mph for a 12 flat is a tad high trap speed from what I see at our local track. 111-114 is normal for most of the cars at our track. N/A ones.

AlkyIROC

Like I said. It was a bad combination. The 117 mph was with 3.27 gears. Going to 4.10 and a taller tire was much better. It allowed me to max out in each gear and the car was maxed out as I crossed the finish line.

Since you can take the engine up to 6000 and you're only crossing the finish line at 5200, you can go with a deeper gear for more performance. As mentioned above, you can probably also increase the shift point.

Since you have 3.23 gears, a swap to 3.73 will make a big improvement. I don't think you have enough rpm range to use 4.10 gears unless you increase the tire height to 28".

fasteddi

iTrader: (2)

Ok thanks for the tips. The reason I bring this up is because Since I got my engine set up the way I wanted, I was looking to add gears in the next week or so, mainly just buy them. Its pretty doubtful that I will install them till this winter as the rear end needs work also.

Also 4.10's would be a little to agressive I "think"? I drive the car to and from the track and arround the area on occation. So 3.73 would probly be the answer.

project89

iTrader: (1)

u have 3:23's now so
3:42 would be a 210 rpm increase
3:73 would be a 500 rpm increase
4:10 would be a 870 rpm increase
4:56 would be a 1,330 rpm increase in ur trap rpm

3:73's are what u want. 4:10's would be perfect but once u start going faster u will have to turn the motor as high as i do, being as u have a factory motor i dont suggest it , i wouldnt take ur motor above 6,800-7k max.

fasteddi

iTrader: (2)

Yes I do agree. Honestly im scared to push it to 6k. Thats why I just let off her the other day when I went 123mph. 5900 or so Rpms was high enough. Thing was screaming.

project89

iTrader: (1)

i would have no problems taking ur motor to 6,500 on the drag strip on the street for extended periods of time with the 3:23's may be an issue though
start using stright 30 or 40 wieght oil whe u start crossing the stripe around 6,300 rpms.

also modifying the oil pump bypass helps for high rpm use but its a pain to get the oil pan off.

if u ever have the pan off drop the oil pump take it apart, check the case for clearance from the bottom of the gears to the bottom of the case and lightly file the case to bring the tolernces closer together if needed. and then shim the bypass valve with 2 an washers to increase oil presure

thats how i get my motor to live at 8k rpms and uve seen the data log of me hitting 8,500 rpms, though my valve springs didnt like that to much

ur motor has all the same stuff mine has except for mine having a slightly larger camshaft and stiffer springs

project89

iTrader: (1)

btw does ur car have drum rear brakes ?
if so find a set of aluminum drums, u can also get a hole saw and start lightning the axle flanges.lil things like this help out a bunch

i even lightened the ring gear in my rear but i dont advise that lol i had an nlimited supply of richmond gears for my car

fasteddi

iTrader: (2)

Yea the car does have steel rear drums. I have to say I have never heard of lighting the axle flange with a saw??? I currently run straight 50w in the car. I have 5w30 in ATM because of the fuel injector issue today, so that's all the fresh oil I had at home. I have only taken it to 6k rpms very few times. I remember hearing before that the pump on the trans is not suitable for higher then 6k rpms? Ever hear of that before

project89

iTrader: (1)

its not the pump that has issues, its 4th gear, 4thgear trys to apply when u go over 7k rpms in the 700r4 from centrifical force

u can drill holes between the wheel studs, just dont cut into the outer edge of the flange between studs as this will allow the flnage to flex.

i actually did mine in a milling machine and milled triangles between the wheel studs, but a holesaw should do the trick as well

ive heard of ppl milling the drums but thats not something i think i would do those ribs keep the drums from warping

u could pick up an aluminum driveshaft for 50-70 bucks as well , i never did trust the aluminum shafts though, i ran a 3 inch dom shaft in my car

AlkyIROC

LOL That made my day. I launch at that RPM

project89

iTrader: (1)

heres a pic for ya so u can see what i mean about the axle flange

fasteddi

iTrader: (2)

I got all stock internals. The dont wana kill the poor little thing

Dave I see what you mean with the axles. Thats interesting. Although Ive read that those aluminum driveshafts are more easy to tear up? Also thanks for the inside on the trans and the 4th gear problems, thats why I let off @123mph, the Rpms and woundering if it was going to want to shift into 4th.

project89

iTrader: (1)

700r4 will not shift into od at wot without mods

fasteddi

iTrader: (2)

I though 4th will try to shift in when high enough Rpms exist. Thats not a good thing...

project89

iTrader: (1)

no what happens is no matter what gear u are in 1st,2nd,3rd etc is that at 7k+ the 4thgear clutch pack tries to apply, generating lots of heat warping the clutch steels and clutch plates in the 4th gear clutch pack. it doesnt actually go into 4th.

think of it as riding the clutch in a manual car

if u put ur shifter in neutral and rev the motor up near 7k u will see the car will move foward a lil bit

no matter what rpm u hit in 3rdgear it will never upshift into 4th without some mods.
infact i belive its anything more then 2/3's throttle and the trans will not upshift into od