i have 89 formula l98 with a 700r-4 all stock with 60000 orig miles when i jump on it the car shifts at wot at 4800 rpm is that normal or should it rev out higher thanks and if so what would cause it to shift early car runs and shifts fine during regular driving

 

that almost seems high for a stock tpi. mine is around 4200-4300. at 4800 they are running out of steam from what i have read, but mine could be shifting to early. when its about to shift if feels like the power is gone.

 

ok thanks

 

It should shift around 5500 at red line

 

wow i am not even close what would cause it to shift so early

 

Maybe try and adjusting the tv cable

 

Maybe check the accuracy of the trim package (note I did not say "instrument") in your dash?

Should be around 4000 or so.

 

If it is a TPI car you will not see any higher than 4850, they hit a wall and do not go any further unless you modify the unit.

 

100% correct, atleast for 1985, and for the 85 year model its still pulling very hard!

For peanut Cam TPI it will stop pulling earlier.

 

maybe on a 305tpi but i know my car (l98) wont pull passed 4600

 

yes it is l98 tpi so sounds like 4800 is ok for that engine correct

 

It should shift at the red line at full throttle

 

Ummm........... no.

Unless whatever "red line" you're talking about, is at about 4000 RPM.

It should shift at around 4000.

Check the accuracy of your tach. My money says, it's reading WAY high.

 

Depending on what motor you have from the factory will detemine the WOT shift point. The standard V-8 will have the 4,800 - 5,200 rpm WOT governor and matching valve body. The High Performance V-8 will have the 5,400 - 5,600 rpm WOT governor and matching valve body.

 

great thanks it is the L98 5.7 all stock a little porting of the runners and plenum, also have UD pulleys otherwise stock

 

Exactly, I think if the motor was considered an HO version such as the 85 tpi where the redline is 5500 it will get the 5400-5600 shift gov.

Hey Pro Built, what would be in the VB to make it match?

 

Ok so your telling me on the 89 l98 where peak HP is 4400rpm your going to keep going another 1k rpm loosing hp? What's the point there? I want it to shift and start pulling again. But each to there own.

 

NO, I am not telling you that.
GM did it. The fact is, that there are maybe a hand full of governors made for our cars. GM did in fact use a 5400-5600 rpm shift governor in the TA Z28 and Corvette, they have diamond style weight and a blue and red/black governor springs. The 5400-5600 rpm governor was also marked in orange paint on the head of it.

TV cable setting and the valve body also have to match along with VB line pressures etc. its very complicated I know pro Built guy can get in detail.

in 1982-1984 there were several TA's that were recalled because the shift governors were set to high and caused valve float.

If you are asking me as a person of I want my 1985 IROC TPI to shift at 5500 rpm, my answer is yes because that is the way GM built my car.




I know they made one for a, diesel, V6, standard V8, and than a HO V8
If your vehicle or V8 redline was at 5500 in 1985 or so you got a HO V8 governor.


There is an art to programming shifts and the best most consistant shifts are done with the your vehicle in D and let your transmission shift for you. There are lots of guys in bracket racing and others that spend lots of time setting up governor weights for a specific vehicle and motor combo.


To set up a car correctly you dont shift at exact peak power, you have to factor in TQ curve, rpm drop (tranny gear ratios) etc. Some motors have little to no TQ Some have all TQ. Weight of car, traction etc.

The rule of thumb with track testing is to shift 500-1000 rpm over peak power and work your way from there and its effect on your ET.

 

here is an excellent article on when to shift.

http://www.allpar.com/eek/hp-vs-torque.html

 

Either way a stock TPI Dies at 4800-4900 RPM no more air it wont see 5500, if that motor was to turn 55-5600 RPM it may do it a few times. The stock internals would not stand up to those kind of high revs, you will break some thing in that bottom end.

 

I do not agree these motor can shift at redline all the time in normal use and maintainance. It would be interesting to see my car down the 1/4 mile one run shifting at 4800 rpm and the other one letting the tranny shift it at 5500. My bet is that if I let it shift where it was programmed it will be quicker.

The point is in having a quicker car you dont just shift at max TQ or HP
its a complicated formula and lots of track testing, You have to know where your next gear will land you in the rpm band etc. because our transmissions have different gear ratios you may want to shift out of 1st later and then 2-3 earlier as the RPM drop may put you below or above your TQ band.

 

ok great so from what i am gatering is that for being 1989 l98 shifting at 4800 wot is about right and an 85 at wot will shift at atround 5500 thanks

 

Again he asked about a TPI car, they will not HIT 5500

 

this thread may be a little aged, but people still want others experiences. My 91 L98 shifts best for me at 4900-5000. No major upgrades. I cut out the splash guards, k&n, 54psi wot fuel pressure(that's as low as it would let me adjust), air foil, 24lb injectors(freebees)others quit working. The consistency isn't accurate on every shift. It may go 200rpm to 400rpm higher next wot in first. Its seen 5400rpm before, sounds as if its trying to take a crap without success. The fluid is good. You just have to tinker until it does best at the seat of your pants feel. Better it shift early than late, you can always hold it manually and shift.

 

Car was stock at the time besides exhaust. Tac showed 5500 RPM shifts. When I data-logged, it showed it actually shifting at 5000 RPM.

 

Ah, the never ending 700r shift point dilemma, lol! First, speaking from experience, maybe others with same experience can chime in, all tpi 700's are NOT created equal! First, I've only ever driven an 85 tpi car once, and that was in 1988! But, I will never forget how that thing pulled like a freight train compared to my 305 87! Can't actually recall the shift points tho, sorry. Anyway, for some reason GM changed the valve body (and maybe governor) from the 87 to later l98 cars. My 87 bone stock will leave 6 feet of rubber on the 1-2 shift. Try doing that with an 88-up car. My current 87 l98, 1-2 shift is around 4800, even if I keep the shifter in first. Second gear, under WOT, will let the motor rev to over 6000 rpm, but will not upshift unless I let off the throttle. The 86 I had did the same thing after I put the zz4 in it. But that motor was still making power at 6500 These transmissions were far from perfect from the factory when new. Find a good transmission guy that actually knows how to work on a 700 and tell him what you want it to do...