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You've gotta be shitting me. You seriously can't grasp that even free revving, if an engine is revving up, hits 8400rpm, and fuel is cut, Exactly. The flywheel does have some inertia, so in some cases it could be possible to get a 100-200rpm bump post-fuel cut - but it takes actual ENERGY input to accelerate the crankshaft, pistons, etc.In fact it takes energy even to hold them at a constant rpm. When you cut the fuel, it's like switching the key off. The engine speed is not going to continue to rise 1200rpm. I won't call you stupid, but if you actually think that the engine speed could continue to rise that much after cutting the fuel... you definitely don't have your head wrapped around the dynamics involved. 2-step rev limiters don't even cut fuel or spark completely, and they are able to hold an engine at a fixed rpm, they don't way overshoot. That would be ridiculous. Rev limiters in general would be basically pointless. When you cut the fuel, it's like hitting a wall.

hasnt TT wasted enough of your time and money yet? get the vems going once and for all :tup:

Hi everyone. I have been posting over on volvoforums and am slowly discovering that the c70 section is about a ghost town, nobody replies to questions, nobody has an opinion, etc... I have been trolling around here and really like the way the forum is set up and organized. Seems to be lots of helpful and nice people around here. Can wait to get to know everyone. Anyways, in this thread (Which I copied over from volvoforums and edited accordingly) I will document the progression of, what is actually my wife's, 1998 C70 Coupe. I will link to any useful threads I start or find useful during the progression as a resource later on. So... Well it looks like it's going to be a fairly substantial project car, so I am going to keep a record (with pics) of what gets done. We originally purchased this car, a 1998 Volvo C70 HT Coupe, for my wife. She looked at tons of cars and kept coming down to the C70, but she had to have an orange one. Somehow we got lucky and one popped up just a few hours away the same day she sold her old car. It looked to be in pretty good condition, and just needed a PCV system and maybe a wheel bearing. I quickly fixed these issues and in the few months we have had the car, we have also had to fix a c/v axle (snapped under very minor torque), drivers side window motor quit, drivers seat quit (Just need to reattach some little spring that came loose, and the car developed a significant oil leak which I and a few other mechanics believe to be coming from in between the block and head, (mind you, the underside was bone dry when we picked it up. Anyways, despite all these issues she still loves the car and so do I (and this coming from a saab/toyota fanboy). I will be pulling it off the road in the next month or so and doing the head gasket, all upper gaskets, timing belt, water pump/t-stat, and most likely pulling and resealing the oil pan. This car was supposed to be a daily driver for my wife, but it i becoming a fairly extensive project, so I will be posting updates in this thread. But first, pics of the car right after picking it up... Alright, I fixed the oil leak. Turns out the hose from the block to the flame trap has a rip in it. I also replaced several vacuum hoses and repaired a bunch of minor boost leaks. Now it runs great! The only problem I an still having is alot of tapping noise from the valvetrain. I tried the ATF trick and it didnt make a difference. So I am assuming I will have to drop the oil pan and change the o-rings. Ok, I got the oil pan job done. It was a pain, buit I feel confident enough to do it again if I had to. I also found alot of other problems though.... The air pump is bad and I did some research and found that the cause is most likely a bad valve where the air blows into the exhaust. Anyways that whole system is bad. I was confused though because there were no idiot lights on in the dash. I pluged the obd2 scanner into the car and found a 02 sensor code (bank1 sensor1) and a rich condition code. I am assuming that they are probably caused by the bad air pump. Anyways, I figured that the cel was burnt out so I pulled out the cluster and discovered that the CEL, ABS, TRACS OFF, and SERVICE lights were all MISSING!?!?!?. Yup, somebody removed all the lights. I replaced the bulbs and now guess what, they are all on. From what I have read, the ABS/TRACS light is most likely caused by a bad ABS module. I called IPD and asked if they could make a tune that ignores the SAS system so I could just block it off. But turns out it is a federal offence to delete a worthless emission system even if I live in an area that doesn't do emissions testing. So I am going to have to fix it correctly. Darn. -------------------------------------------------------------------------------------------------------------------------------------------- My wife has been driving this car for the last couple of years. Finally over the winter we were able to park it and I could start making a list of what all I need/want to do to it. Here's what the plans are: -pass side cv axle -pass side trans output seal leaking -timing belt job/water pump (140k mi and no sign of it ever being done!!!!!! aaaahhh!!!!) -abs control module (abs and tracs lights are both on.) -redo entire front end (everything is loose) -B&G springs -steering u-joint (steering feels like it's binding) -15mm rear wheel spacers -alignment -replace split vacuum elbows on intake tube -air flow directional actuator in dash is starting to go bad -fix several burnt out dash lights -oil/coolant/trans fluid change -install 1998 V70R ecu (yes, I win at the junkyard) -repair drivers window regulator (I rigged it last summer so it kind of works, need to fix right) -derattle sunroof -new headlight wiper arms/blades -new brakes? -some sort of double din screen (stock radio doesn't work) -new speakers all around -and the list goes on, and on, and on... and on......... ------------------------------------------------------------------------------------------------------------------------ This car is pretty much top priority to get stuff done on this year. The first project I am working on is the front suspension. -new mounts -new bearing plates -new end links -new steering column u-joint -B&G springs -MOOG camber adjustment bolts -new bilstein struts were put on a couple years ago and still seem to be in good shape, so I am leaving those Everything went pretty smoothly except for the column u-joint which was a huge PITA. The front of the car is back on the ground though and looks pretty good even after just dropping the jack (springs haven't settled) it looks quite a bit lower. I cant wait to get the back springs in as well. In progress: Rebuilt strut assemblies: One side installed: Sittin pretty and still needs to settle quite a bit: While changing the column u-joint I discovered some significant vacuum leaks due to these cracked and split elbows. I will replace them before putting the intake back together. Also need to figure out why the intake tube is covered in oil. ---------------------------------------------------------------------------------------------------------------------------------------- And the rear is done. The rear is surprisingly easy as long as you can get the car high enough to unload the springs after undoing the shocks. Kind of a weird design for the rear suspension, but it's pretty easy to work with. It definitely needs spacers in the rear now. I'm thinking 15mm. According to the manual the rear is only a couple mm narrower than the front, not sure if its the body shape or what, but it seems like a lot more than that. What size spacers do you guys run on the rear? I'm not trying to hellaflush/poke/etc... just don't want it to look so sunk in. Anyways, Pics: Drivers side: Passenger side: And stance: Yes, the garage is a mess. ------------------------------------------------------------------------------------------------------------------------------- Not too much to report at this time. I killed 2 birds with one stone last night. I replaced the pass side trans output seal and replaced the axle as well. The trans was leaking from that seal and the boots on the axle were ripped. So now no more leak and no more grease all over the wheel. yay! ----------------------------------------------------------------------------------------------------------------------------------------- Finally got my vacuum elbows in from fcp. Threw in a new battery and drove it for the first time in months. It desperately needs an alignment. The ABS/Tracs lights went out almost immediately so hopefully I wont have to get a new module for that yet. The cheap hacked together exhaust on the car is now hitting the rear spring, so I'll have to get an aftermarket turbo-back... darn. Also, the A/C has a leak as it is very low on freon and it was full last summer.... The list never ends, but there is at least progress.

No. Just no. The engine won't "teleport" from 8400rpm to 9600rpm magically. The fact that apparently no one here even grasps what happens when you cut the fuel to an engine... there's just no facepalm that's even sufficient.

If I remember correctly Motronic uses Spark cut as its rev limiter, maybe fuel cut as a secondary hard limiter. Not sure if thats still the case with TT. I can see that the engine can maybe go 100-200 RPM past that but when spark is cut (and fuel) the engine will not rev higher (unless the fuel self ignites which it shouldn't). I have three limiters set on MS and they all work and won't let me over rev the engine. I have a soft limiter that retards timing, then spark cut and fuel cut after that. It never gets to the fuel cut limiter. Please correct me if I'm wrong but thats how I remember Motronic to handle the rev limiter.

Well since Carlisle is over now, he's got no reason to stay with TT.

Huh? You can't blame clutch slip for the motor over revving dude. The rev limiter will enforce the rev limit, clutch slip or not. Assuming it is set appropriately, of course.

:tup:

i agree, dont think i would ever consider using fuel cut by itself as my primary way of limiting revs. either way, the ecu didnt limit the revs, for what ever the reason. Sure the clutch slipping would let it climb quicker in the rpms than if it was grabbing but thats why we have rev limiters, if its not going to function when you need it the most whats the point in having it. im sorry but H, your car just keeps proving to me that TT sucks lol. Your car is going to rip on the vems at 9k rpm :tup:

stuff T!!! yeah slipping of the clutch would explain the 9600rpm. Spec clutch?

Um, then you go drive your car at WOT and put the clutch down while holding down the gas and see your revs climb 1200 rpms slower than it normally would with the clutch engaged.........-__- And you cant grasp what happens when the fuel gets cut to the engine in this case, cause it didnt happen.

That is quite possible, 20 psi on a large turbo + sudden slip of clutch/no connectivity to drivetrain could cause the revs to "teleport" north.