floman

iTrader: (54)

I purchased my 98 SS back in Nov 2012 from a forum member in Sugarland,Tx. I will list the mods that the car had at the time of purchase and what the previous owner stated that the car dyno'd and the track times he stated.

Car: stock bodied 98 Camaro SS, T-top car with full power accs and leather interior, A/C still intact. Car is full weight with no weight reduction done at all. Race weight is actually heavier than a stock SS due to the addition of the heavier aftermarket suspension parts and the Moser 12 Bolt rear end.

Engine: 2007 L92 engine from and Escalade, stock crank & pistons with Compstar rods, minor cleanup on the stock heads with lightweight stainless valves & Pac beehive springs and YellaTerra rocker arms. Comp Cams hyd roller 232-246 dur @ .050" with .595" int/ .613" exh on a 115 LSA. FAST 102mm/102mm setup, TSP 1 7/8" LTs, 3" ORY merged with a 3 1/2" discharge over axle into a Borla XR1 racing muffler 16" x 6 1/4". HSW nitrous system with Zex plate and Nitruos outlet window switch (150 shot)

Trans: Century Stage 2 4L60E with a Circle D 3600 conv ( not sure on which model # it was, but it seemed pretty loose when driving the car)

Rear axle & suspension: Moser 12 Bolt rear with Tru-Trac diff and 33 spline axles w/ 4.11 gears, Sphon extreme duty driveshaft, Sphon Pro Series torque Arm, BMR lower control arms, Panhard bar & relocation bracket. QA1 "R" series front shocks & 300# coilovers, rear QA1 single adj shocks w/ 150lb coilovers. Stock K-member with factory control arms. Stock brakes w/ drilled & slotted rotors.

Wheels & tires: Billet Specialties Street Lites 15x3.5" front runners w/ MT Sportsman 28" front skinnies, Rears 15x10" F-Body specific w/ MT 275-60-15" Drag Radials

Previous owner stated 470rwhp dyno ( unspecified rwtq) and best track pass of 11.20 @ 121 mph on a 1.58 60 ft. Estimated raceweight of 3575 lbs.


Fast forward to Purchase: First thing I did was take the car to Geoff Skinner @ EPS to have him check the tune and try to troubleshoot a tranny issue with the torque converter not locking up on a consistant basis. Geoff spent all day on the tune and we concluded that there was a mechanical issue with the converter clutch.

Dyno run showed a peak gain 10hp at peak and as much as 15-20 at certain points during the pull. I was disappointed with the final #s of 432rwhp/410rwtq. Made one pull on the 150 shot nitrous at 583rwhp/ 495rwtq and blowing through the converter. (Dissapointed, but it is what it is)

Three weeks later the 4l60 started acting goofy and went into limp mode. At this point I am leary of the tranny and don't want to sink anymore money into the 4L60.

Fast forward 5 months later: I purchased a brand new 4L85E from GM Performance Parts, FTI 9.5" Billet triple disc 3800 nitrous converter, TCI SFI approved Flexplate, BMR 4l80 crossmember, Sphon "Top-Gun" seemless chromoly driveshaft with "Strange" chromoly slip yoke, B&M stackplate cooler with fan. Tranny is controlled with the stock 98 PCM using the "slow67" relay mod.

May 18th: Evadale,Tx @ "Ben Bruce Memorial Raceway Park. Made two passes in 86 deg high humidity weather at + 2000 DA

Car is driven to the track , approx. 75 mile round trip.

Motor passes only
1st pass: 11.71 @ 117.9 mph on a 1.71 60ft - tranny shifting early at 5700 rpms 1st-2nd, and 6200 rpms on 2nd-3rd, thru traps @ 6200 rpms, launching at 2000 footbrake

2nd pass: 11.76 @ 117.6 mph on a 1.74 60ft, same early shifts and launching off idle and flashing the converter.

Friday June 7th: Evadale,Tx at "Ben Bruce Memorial Raceway Park" Friday night street car "instant green"- Temp 72 deg with approx. DA +1179 ft

Car is driven to the track, approx. 75 mile round trip.

Motor passes only
1st pass: 11.45 @ 119.6 mph on a 1.68 60ft, manually shifted tranny on 1st-2nd(6500 rpm) and over shifted into "D" and computer shifted 2nd-3rd at (6200 rpm), launch at 2000 footbrake.

2nd Pass: 11.27 @ 121.04 mph on a 1.639 60ft, manuall shifted at 6500 rpm at each gear change and through traps at 6500 rpms, launch at 2000 footbrake.

3rd pass: 11.27 @ 121.16 mph on a 1.644 60ft, manually shifted at 6500 rpm at each gear change and through traps at 6500 rpms, launched at 2000 footbrake

Overall I am very satisfied with the results so far. My raceweight at this time has increased from what the previous owner was at, and is now a hefty 3775 lbs with 5/8 tank of fuel and my big ***(260lbs) and the extra 75 lbs or so added by the 4L85E and related install items. I fully expected the car to be slower due to the increased weight and the milder gearing of the 4L85E and added mass of the internals. Also the FTI converter is not as aggressive on the launch as the 4L60/Circle D setup.

To say the least, I am impressed so far, (although it was not a cheap swap) and I hope I have gained a lot of reliability at the same time. I also realize that this swap is probably overkill at my power level, but its something I can grow into.

Blackbird-WS6

iTrader: (15)

very nice to hear this type of info. most people that do the swap never post up afterwards.

what are the rpms at 80mph and how tall rear tire??

does the car feel sluggish?? i know the times state diff but i just want to know how it feels wise. i know some people have said it feels sluggish but never reported back.

how much is the 4L85 from GM??

ill be doing the same swap soon. (T56 to 4l80)

floman

iTrader: (54)

Rear tires are 275-60-15" M/T Drag radials approx. 28" tall

Have not really looked to see what 80mph is, but 75 mph is right at 3050 if I remember correctly.

I guess as far as it feels, I initially thought there was a noticeable difference not having the steeper 1st gear of the 4L60E. I guess I kinda find myself paw-paw driving around the neighborhood and down town due to the volume of the 3 1/2" exhaust ( I replaced the Borla XR1, and replaced it with a Dynomax 3 1/2" bullet in the I-pipe and a 3 1/2" Hooker Aerochamber in the rear section after the over axle turn. But, I gotta say that with just a small amount of throttle (1/4 throttle) it steps out pretty quickly from a dead stop.

I got a local friend that works for a chevy dealership look on their parts locator to find it for me. Mine is the 4L85E Supermatic version that is rated to go behind the 572" Big Block crate engine 720hp/685 ft lbs of tq. In February they were on national backorder and his locator found 4 available nation-wide. I bought mine from a dealership near Ft. Smith,Ark. Tranny listed for roughly $3500.00, and they sold it to me for $2949.00 shipped to my door. What helped me decide on this tranny was the fact that it is a brand new zero mile unit, not some 100K mile rebuilt tranny core. I bought everything to do the swap brand new, nothing used and only good reputable brand name parts.

So far the tranny has operated flawlessly, other than my tuning in-abilities. If I can figure out why its shifting out slightly early. Other than that, everything is "golden". I was afraid that I was going to slow the car down ( and that was acceptable for more reliability) but to my surprise the car seems to be just as quick as the previous owner claimed and I am at a 200 lb heavier raceweight.

Good luck if you decide to make the swap.

Blackbird-WS6

iTrader: (15)

I thought the rpms would be little lower.

Anyways thanks for all the info. That bmr crossmember give you any problems? I know somw people have had problems with it not clearing the trans.

floman

iTrader: (54)

I have 4.11 gears with the 28" tires so its gonna spin up a little still. But, it cruises nicely at 65 mph. The 4th gear ratio is not quite as much of an overdrive as on the 4L60 or the T56s.

I had to slot the holes out on it a little to get the crossmember away from the back edge of the trans pan lip. Was not too big of of a deal

KirkEvil

iTrader: (36)

Thank you for posting results on the swap. Did you get the shift points retuned after changing to the 4l80 or do you just prefer to shift it manually?

floman

iTrader: (54)

I'm still trying to get it figured out. I'm just a real newb with the HP-Tuner thing. I have scaled up the shift tables to compensate for the gear ratio differences in part throttle and WOT tables and have the commanded shift rpm set at 6500. Seems no matter where I put the WOT mph setting it still shifts out @ 5700 & 6200.
I did some adjusting on the mph settings a few days ago and went for a test drive. Same result, shifting out early. So, I decided to try manually shifting it. I clicked the shifter into 2nd at 6100 rpms and the tranny shifted right at the rpm set-point of 6500rpm, then clicked shifter into 3rd at 6100 and again the tranny shifted right at the set-point of 6500rpm. It just seems like by holding it out manually to get past the early rpm, it then goes by the commanded shift preset of 6500 rpms?
I just thought I would try it, and I'll be danged if it didn't. But, I still want to get it figured out. Need to learn how to data log with the HP-Tuners and see what is really going on to see what the computer is seeing and what it is actually commanding. I have no doubt its probably something I am missing since I am new at the tuning thing.

LongIsland63SS409

iTrader: (22)

Thank you for posting the dragstrip results!
What is the rpm at 65 mph with the 4.11 rear and 28" tall tires?


Thanks,
Mike

floman

iTrader: (54)

I'm gonna say its about 2800 at 65 mph. Next time I drive it I will make it a point to get exact rpms at 65,70,75,80 mph. I do know that around 65-70 mph is not too bad considering the 4.11s. I drove about 75 miles round trip to the track, made three 1/4 mile passes and only burned about 3/8 tank of fuel.
I am just so happy that the car still ETs & mphs the same as it did before the swap. It feels different with the milder ratios, not quite 60 footing as hard but that could be the difference between a really loose 2.5 STR 3600 Circle D conv and the tighter feeling FTI 2.15 STR 3800 nitrous spec conv. I am only guessing that the 4L85s closer ratios are helping once the shifts are made.

Cant wait till the fall and winter cool air gets here, just a shame it took me till May to get this conversion completed. I am not far from Houston and in the winter we can get some good negative DA air after a strong cold front, and Royal Purple Raceway ( Houston Raceway Park) is one of the top tracks in the country. Should drop another couple of tenths in good air.

pk222

I don't know if your using the stock computer or not but I heard the 98 computers were hardest to tune. This is just stuff I've heard about and never dealt with myself. Anyone know if this is true? I've had 2 98 and a 99 all autos. I'm going to be getting my current 98 tuned soon and would be nice to know if this is BS or not. So I know if I should look into a 99+ computer swap

floman

iTrader: (54)

Yes, I am still running the stock 98 PCM. Yes, a lot of people say they are not as good as the later 99 up PCMs. But, they can be tuned just fine if you really know what your doing.I had the car dyno tuned by Geoff Skinner @ EPS in Baton Rouge,La. This was before the 4L85E swap, but he lined out a few issues with the tune, especially a terrible cold start issue and also gained 10rwhp at peak and 15-20 at some points in the power curve. Engine is a L92 with decent size cam and FAST 102/102 setup. He managed to get it tuned out very nicely.

The issue with 4L80 swaps is that the 97-98 Corvette and 98 F-body PCMs do not have segmented tunes. The tune is all one big tune, so you cant do a tranny segment swap. Its either do the "relay mod", swap to a 99 up PCM and segment swap, or buy and aftermarket controller, or bite the bullet and go with a manual valve body.

pk222

I was looking into the 4l80 swap also but im only hoping for 12s so I don't think its necessary. I was just curious if that could be your problem

floman

iTrader: (54)

I opted to control the 4L85E with the "relay mod" method. The tranny operates pretty much flawlessly except for the fact that I have not gotten the "wide open throttle" shift points exactly where I want them. Its just a matter of my inexperience with tuning I am pretty sure. I'm not too concerned at this point as I am sure its something small that I am overlooking.

I'm sure the 4L85E is overkill at my power level also. But, the car is running the same #s as it did for the previous owner with the 4L60E setup and it was 200lbs lighter then. So, I would say there is no real problem other than my wallet is a little thinner after the swap was all said and done( OUCH!)

I am very pleased with the results so far. Plus, I know this tranny is gonna live longer than the 4L60E did for the last owner ( 4L60E was built 3 times since 2009) there is no way I was sinking any more money into that pit!

silverz28camaro

iTrader: (20)

Nice results, I am a fan of the 60e if built right,very hard to do and then u need a top notch converter also. I had both the 80e and 60e in my shop 136lbs for the 60 and 186 for the 80 ...without converters

silverz28camaro

iTrader: (20)

Fwiw I just went 9.89@140 in my homebuilt 60e, shifts and lockup is very consistent

pk222

I would like to do a t56 swap instead but my budget is the deciding factor. I have everything priced out now with my rebuild a yank 3600 a Trans cooler fluid U joints and a tune for around 2300.

floman

iTrader: (54)

Yeah, I agree that the 4L60s can hold up, but I've just seen too many of them fail. Since I was going to be spending a good bit of cash, I decided to go ahead and do the 4L85.

Yeah, half of the extra 200 lbs I was referring to on the heavier race weight is my big *** ( I am about 100 lbs heavier than the previous owner) I figured about 75 lbs for the 4L85 and another 25 lbs for the heavier flexplate and BMR crossmember and an extra Hooker Aerochamber muffler I had welded in the exhaust to quieten down the loud exhaust note for friendly (somewhat) neighborhood cruising.

floman

iTrader: (54)

Congrats on those times, that's hauling some ***.

I hope to run some low 10s on the 150 hp shot soon. Just want to put a little more time on it before I hit the juice. I hope maybe to see 10.20s-40s and maybe 128-130 mph? Not really sure, but maybe that's an attainable goal?

evillsx

iTrader: (7)

I would think you could hit 9s from where you are on a 150 shot?

floman

iTrader: (54)

That would be so awesome. Just hope the suspension and tires will hold the shot out of the hole. Low 10s I would be satisfied with, But high nines - I would be ecstatic