Anyone runin with the exhaust cam retarded 1 tooth?

[3literpwr]

Guys When I built my motor/car I retarded the cam gear one tooth as recomended by some people, but im not sure if i can benifit from this as
I rally the car and run a restrictor which only allows me to rev the motor to 5800-6000 rpm...... My question is should I go back to stock? I never drover the motor with the timing at stock so I dunno If its worth my time????


Thanks
Larry
#622 Scca Club Rally

 

[MitsuBoost]

If im not mistaken, retarding the exhaust cam would yield more valve overlap...which isnt good for boost.

 

[RiceKiller_TSi]

I doubt you're getting gains from that mod... never heard of doing it either. It's better to replace the stock cams (if possible) with upgraded ones with larger lobes for more power.

 

[3literpwr]

I plan to switch it back this week.......

thanks for the input


Larry
#622 Scca Club Rally

 

[kpt4321]

Just dyno it to see if it's a worthwile idea.

 

[GTM]

Originally posted by 3literpwr
I plan to switch it back this week.......

Is there any reason you don't use adjustable cam gears? I've not looked at the data of recent but causing the exhaust cam to open 2-3 degrees later may yield a bit more power. However moving 1 full cog may be close to 5 degrees which would then defeat your attempt to get more breathing by extending the overlap.

I don't think you can condem the turbo as loosing power without knowing where the power band has been designed. Of course going to extremes will have a negative effect but you have not established this has happened.

Cheers,
GTM

 

[Rogue_Ant]

I believe its actually closer to 7degrees...

Rogue

 

[GTM]

Originally posted by Rogue_Ant
I believe its actually closer to 7degrees...

Rogue

Hehehe, I counted the cogs some months back off a picture... must have missed a few. How many??

Cheers,
GTM

 

[white 2g awd]

http://dsmtalk.com/forums/showthread.php?threadid=110887

 

[Rogue_Ant]

48 Teeth....
7.5 Degrees.


Quite a change...

Rogue

 

[GTM]

Originally posted by white 2g awd
http://dsmtalk.com/forums/showthread.php?threadid=110887

What was that all about? If there was some point in directing our attention to some site you should state what we were supposed to be looking for. Frankly I saw nothing there that I didn't know and the rest was urban legend. There is more factual info to be found here on DSMtuners.

Cheers,
GTM

 

[GTM]

Originally posted by Rogue_Ant
48 Teeth....
7.5 Degrees.

Quite a change...
Rogue

Wow, huge jump if you are looking for extra hp especially at low rpm. Thought I'd seen some of the aftermarket verniers boasting 2.5 degrees which may not be enough depending on cam profile.

Thanks for taking the time and counting.

Cheers,
GTM

 

[Defiant]

Originally posted by GTM
Is there any reason you don't use adjustable cam gears?

If he's running SCCA, that'd be the reason. I think they have a rule about what toilet paper's allowed in the Porta-Sans.

 

[DSMRevolution]

Before I did my timing belt for the first time maybe a year and a half ago, the previous owner did it first. The idle was really bad, but it ran strong. When I pulled it apart, I noticed that the exhaust was off maybe 2 teeth. I put it back together how it was suppose to be, checked everything with a timing light and took it for a drive. It wasn't as strong anymore, but the idle was a LOT better. I think I was lucky I didn't hit valves with how it was before. Another thing though, the previous owner was a farm boy (well adult). I asked him how he went about adjusting hydrolic tension and this is what he told me... "Well you can usually tell pretty easy when a belt is too tight or too loose so I just adjusted it until it felt right." :laugh: :laugh: :laugh:

 

[Rogue_Ant]

Originally posted by Defiant
I think they have a rule about what toilet paper's allowed in the Porta-Sans.

:laugh:

Rogue

 

[GTM]

Originally posted by DSMRevolution
...
It wasn't as strong anymore, but the idle was a LOT better.
...
the previous owner was a farm boy (well adult). I asked him how he went about adjusting hydrolic tension and this is what he told me... "Well you can usually tell pretty easy when a belt is too tight or too loose so I just adjusted it until it felt right." :laugh: :laugh: :laugh:

Farmers make their living off their equipment and have a lot more skills than you seem to think. There is no AAA, no curb side service, the parts store isn't just around the corner and they must be resourceful. At least he was smart enough to know when to bail out on a high maintenance piece of equipment which had more power before you fixed it.

Cheers,
GTM

 

[3literpwr]

Well I reset the timing to stock last night. At first It seemed that the power came on about the same time, but the curve felt a bit flatter.....
Im really sure how much of a differance it make but I think I will keep it at stock until I can get a cam gear and get on the dyno......

My main concern is quick spool and good low/mid range power to help keep me out of the tree's......

Larry Parker
#622 club rally

 

[RiceKiller_TSi]

Good luck Larry, let us know how it all turns out after the dyno!