How sensitive is your CSU carb jetting changes?

I know a cog would be ideal, but with a 5spd and lots of street miles I would worry about breaking be belt during gear changes or quick changes in rpm. One of my good friends is making 20lbs on his 347 with a T-trim, 6.87 crank, and a 2.75 blower pulley. It does slip sometimes and only makes around 15-17. I realize that big YS might take a little more stank to turn, but I'm willing to give it a try. Hell, it's about all I can afford at this point!!! BTW Tim, got any pics of your car. How far along are ya

 

How sensitive is your CSU carb jetting changes?

Would it work with a passenger side mounted YS? I have heard there arent as many options for them.

 

How sensitive is your CSU carb jetting changes?

Here is my thought on the belt deal. I don't think you would have any problem with the stick and the coge. A pulley is a pulley so I will find out what he has and what he wants for them and let you know. You never know, good for the track.

A coge belt has little to no tention on it at reast, no oil pressure at rest, You start the motor takes some time for oil pressure and still little to no pressure on the belt or the front crank bearing. Now a hard pull, lots of oil volume and increased blower belt load, but they are there together.

Regular belt, you have to put a lot of tention on that thing to keep it from slipping, when at rest still a ton of tention and no oil pressure. On start up you are pulling on that belt from the tention on a bearing that has no oil pressure when it starts, not good, then you have pressure, and oil is there as pressure/slip happens. I just don't like that kind of pressure on the crank with no oil

I will have some pictures tomorrow or the day after. Still no engine, have a very bad lean condition on the dyno. Hope that problem is solved and when it is, I will let everyone know.

 

How sensitive is your CSU carb jetting changes?

Ok, let me know. I have heard of the cogs stripping teeth during gear changes on a stick car due to the quick change in rpm. Being a 90% street car I would have to give 2-3lbs of boost up for better street reliability. If you dont mind just PM me when you find out how much money the cog setup would cost. I'll do a little more research and see what I can find. I do see your point with the crank snout pressure at startup, I had never really thought about that pressure when starting the motor

 

How sensitive is your CSU carb jetting changes?

Ya, with that pulley combo the rich cruise issue shouldn't be much of an issue espeicaly with a 5 speed and the OD...

Once you start to lean on I think that you will find belt slip will be a major problem at the higher RPM's... The 6.8 crank pulley will give you slower belt speed than an 8" but you will have less pulley surface to grab the belt so it is kind of a trade off... One of the most important issues with an 8 rib setup and getting the belt to grab is having a super stout bracket setup and good idler / tensioner pulleys... The Vortech Passengers side mount is a pretty weak setup and once you start to really crank on the belt the bracket is going to flex and this will cause problems... Slip, throwing belts , etc... Once you get a little further along with your ride and the dreaded belt slip becomes a problem I can offer some suggestions to address the problem...

FWIW, I would not even consider using cogs on a street car.... They are way to problematic and hard on things for what your wanting to do...

Good luck!

 

How sensitive is your CSU carb jetting changes?

I ran a coge belt on my Wild Street Car, on the engine dyno and coutless trips to Sears (hang out) with no problems. I am not saying I would drive 300 miles at a time, but it gets a good amoutn of street driving. I used this same belt for 3/4 of the season before replacing it just because. I still have it and would use it in a sec.

What problems come with a coge set up. Just wondering not saying there can't be any problems, I just have had good luck with mine and no blower brace.

I guess I don't see how they are any harder on parts with slack or light tention on them 95% of the time compared to 100+ lbs of tention on your belt 95% of the time to keep the belt from slipping. The belt combination your talking about in your own words you said problem like 4 times when discribing its function.

Just wondering, so I know what to look out for.

 

How sensitive is your CSU carb jetting changes?

Dave-Thanks for the advice, I am gonna try to see how far I can go with this setup. I was hoping I would reach my tune limits regarding pump gas before I ran into problems with belt slip, but experimentation will tell. You may be hearing back from me on that one. Have you ever tried bead blasting your pullies, I have a cabinet out in the shop.

Tim- Thanks again for the replies. Most of the people I have talked to have had trouble with the cogs on a stick car. The converter slip in the auto cars seems to buffer the shock of sudden rpm changes and helps the belts live a little longer. So I guess it probably is easier on engine parts, but my application would be at a high risk of shredding the teeth off the belt. I will be driving this car on 200mi+ one way road trips, and I have to comprimise to the side of reliabilty on this one

 

How sensitive is your CSU carb jetting changes?

What is you goal on boost level, what psi.

The reason I ask is the REN cars will kill a belt in one or two passes because of how tight they have to be to obtain consistent boost levels. I mean they kill them.

Cool, it was a suggestion and it might not be the way for you to go. That is cool. I am still intrested on what to look out for on a coge set up. The belts are expensive, but if they live as long as my first belt I will be happy.

Remember a carb and blower don't make a good combination for the street. LOL

 

How sensitive is your CSU carb jetting changes?

I guess my goal is as far as 93 octane will take me. With conservative timing(18-20deg locked) and a mid 11:1 a/f, I am guessing I will be nearing detonation around 15-18lbs. I am just going to keep creeping up on my limit til I can go no further or I am happy with the power. For now

 

How sensitive is your CSU carb jetting changes?

You will always want more. Good luck, sounds like a solid plan.

 

How sensitive is your CSU carb jetting changes?

You are probably right, but I'm gonna just keep lying to myself for now

 

How sensitive is your CSU carb jetting changes?

Hi Tim,

The problems I see with using the cog's on droptops setup is the fact that he has the passengers side vortech mounting kit... It is not very strong due to the way that it is designed... If you have any mounting flex issues with a cog it will throw the belt right off... Also the only cog setup he could run without doing a lot of mods using that bracket is the 35mm cog kit... The 35mm belts are not near as strong as the 50mm belts and combine all this with a stick shift and it would be touchy setup to get working well...

The vortech's and Novi's can not take the sudden shock of snapping the throttle blades closed as well as a Procharger due to how they are designed... these blowers will self destruct fairly easy when you spin them hard and lift fast... example after a 1/4 mile pass... A stick shift would make matters worse...

Here's the results of 50mm cog Novi 2K being spun at 65,000 RPM's and snapping the throttle closed after a 1/4 mile pass...

My buddy did this two different head unit's and the 2nd one was with a brand new Novi 2K race unit... It lasted about 3 passes and self destructed! The truck has and auto transmission and the huge Vortech bypass valve (the new one like the procharger units) He now has an F2 procharger and it has taken the abuse so far although he has pitched a few belts with it...

Everything about your F2 is designed to be used with cogs by Procharger, make 25+psi and take the abuse... The head unit, solid mounting brackets, good idlers, etc. which is totaly different than a passengers side mount vortech kit that is basicly designed to make 6psi with a 6 rib using an A - Trim... The design is from like 1990 and works OK if you want to keep it mild and retain the use of all the accesories... Myself and many others have made custom brackets, braces, etc to fix these mounting flex issues that is all to common with that type of kit...

Your right what the renegade guys do is absolutly insane! hanging a 200+ pound guy off the end of a 5 foot long pipe to tighen the belt, massive strut brace between the crank and the blower, eating all the ribs off the belt in one pass using an ultra grip pulley is all just a little to crazy for me... :jawdrop:

A "street car" means different things to different people and I get the impression that droptop wants one that he can drive all the time without any major issues... I think his plans are probably quite different than what yours are...

I'm just trying to help! :tu:

 

How sensitive is your CSU carb jetting changes?

Sounds good to me, Droptop has a solid plan, we both were just trying to help, I have experance with a Vortech only with a Serp belt, I have a S-trim on my 95 Cobra, it has performed very well since day one, I think Vortech makes a good street blower, but ProChargers can take abuse.

All very good points, thanks for the information.