does engine compression ratio affect drivability?

[Ironside]

Hey all
This is been on my mind for quite some time now and i can never get a real answer from anyone.
Question: does engine compression ratio affect drivability? im asking this because ever since iv installed my Tomei Poncams iv noticed that the drivability has been terrible.
I don't mean by the fact that the idle and loss of bottom end take off's are a downfall
I mean by the decompression and instability of going from acceleration to deceleration. At times its almost to a point that im afraid im going to snapping my drive shaft.
I have been told that by installing poncams it will change the engine compression ratio, but everyone ses that this dose not effect the drivability what so ever.
Am i alone here or dose anyone else get annoyed by this.
I think im going to install the OEM cams back in anyway since i have the VCT sound of death.

 

[S15_SAM]

How does installing just cams effect compression ratio's??? Never ever heard that!! And snapping drive shafts, do you mean when you let of the accelerator it shuts down vilolently? If so probably to do with the map and running a non recirculating dump valve!

 

[Ironside]

yeh i also thought it was the map and the fuel cut off point, but was told that it isent the case. but yeh i have alot of decompression

 

[S15_SAM]

What do you mean by alot of decompression??

 

[PIIPete]

I would like to know what 'drivability' means!

 

[PIIPete]

I would guess that if you mean the engine doesn't run well, you may need a remap (i.e adding something like the nistune daugterboard to the ECU), as the ecu is programmed for standard parts and you have changed things.

 

[Ironside]

by decompression i mean by how a engine can reduce a vehicle speed as how a truck uses a exhaust brake or how rally drivers use decompression lock up. I got a Apexi Power FC D-jetro so i can re-tune it but its gonna cost about 800 bucks. was thinking of just restoring back to OEM ECU with OEM cams and injectors.
By vehicle Drivability

noun Automotive .​

the degree of smoothness and steadiness of acceleration of an automotive vehicle: So by drivalility i mean i don't want to worry about jerking every signal gear change, its pissing me off and its ****ed my drive train. i think my CV joints are ****ed or something, there's a clunk coming from the rear hubs now because of this jerking around.

​

 

[Auss15]

You have to remember when you make a significant change to the engine internals you will need a retune. Cams are an example, you have changed the lift and duration so you will need to check your AFR's and timing. If your'e not prepaired to pay for a retune then put the stock cams back to maintain driveability.

 

[Ironside]

yeh i think i might cut my losses and got back to OEM
Iv had 3 re-tunes now. i told them i want driveability over power. If this is the best they can do then im going back to OEM. But agen i have had a few people saying that cams liek these do change the compression ratios. i dont know how though? i was even told to get a thicker head gasket and it should be fine.

 

[Auss15]

Wow, talk about miss information. Compression ratio is exactly that, the ratio between the the cylinder volume compared to the combustion chamber volume. Yes you can change the comression ratio with a very agressive inlet cam say around 295 deg but not with a Pon cam of 256 deg.

I've had Pon cams in for 8 years and they have been the most reliable and easy to tune cams one could want. They were always design as drop in cams that can still retain the stock springs.