Adding a lower pulley

sonic02gt

Kona Blue shelby
Joined
Sep 18, 2005
Messages
1,533
Reaction score
0
Would i see a big difference with adding 4lb lower? and would i have to run 100 octane all the time i have 17lb now with 2.4 kenniebell :confused:
 

FuelSlut

FK RED STAR
Joined
Nov 9, 2005
Messages
1,969
Reaction score
0
Would i see a big difference with adding 4lb lower? and would i have to run 100 octane all the time i have 17lb now with 2.4 kenniebell :confused:
No if you stay around 17-18 psi 93 octane is plenty. If you decide to run more boost than 100 oct is a must.

You will see a difference 4# lower = less belt slip and it aloes you to run a larger blower pulley that also helps with belt slip.
 

Zack

4 Doors 4 Life
Joined
Mar 21, 2004
Messages
6,295
Reaction score
5
Location
NW Indiana
I still have no clue how Cobra owners have belt slip.
So many friggin idlers, stub idlers etc.

I made 26 psi with one belt tensioner and one aux.idler with no slip on the Marauder.

Confused!
 

Bob_Kurgan

Flyin_Hawaiin
Joined
Feb 16, 2005
Messages
3,013
Reaction score
0
I still have no clue how Cobra owners have belt slip.
So many friggin idlers, stub idlers etc.

I made 26 psi with one belt tensioner and one aux.idler with no slip on the Marauder.

Confused!
all about belt tension..
 
B

Boost12

Guest
On my old KB 2.4 I ran a 10 lb lower and never had belt slip/issues ever. I don't think they make a 10 lb lower anymore though.
 

Flatliner

I'm kind of a big deal...
Joined
Mar 3, 2004
Messages
35,000
Reaction score
0
What upper are you running now?

You need to find the right combination for the boost you are looking for. By changing the lower you are increasing the boost and yes, you most likely will have to run 100 Octane or more, but what you could do is buy a bigger upper to reduce the boost back down for a 93 octane tune. You can then have your tuner supply a 93 octane tune on the bigger upper pulley and the 100 octane for the track with the smaller upper.
 
OP
S

sonic02gt

Kona Blue shelby
Joined
Sep 18, 2005
Messages
1,533
Reaction score
0
What upper are you running now?

You need to find the right combination for the boost you are looking for. By changing the lower you are increasing the boost and yes, you most likely will have to run 100 Octane or more, but what you could do is buy a bigger upper to reduce the boost back down for a 93 octane tune. You can then have your tuner supply a 93 octane tune on the bigger upper pulley and the 100 octane for the track with the smaller upper.
thats a good idea i just need more boost. Brother is procharging his vette:D
 

Wiked03

CSVT OG
Joined
Mar 1, 2004
Messages
29,342
Reaction score
0
Location
Louisville, KY
I still have no clue how Cobra owners have belt slip.
So many friggin idlers, stub idlers etc.

I made 26 psi with one belt tensioner and one aux.idler with no slip on the Marauder.

Confused!
IMHO, belt slip issues on 03/04 cobras are highly overrated and usually a result of people running the wrong belt size.
 

blck10th

Well-known member
Joined
Jan 11, 2007
Messages
17,963
Reaction score
9
What upper are you running now?

You need to find the right combination for the boost you are looking for. By changing the lower you are increasing the boost and yes, you most likely will have to run 100 Octane or more, but what you could do is buy a bigger upper to reduce the boost back down for a 93 octane tune. You can then have your tuner supply a 93 octane tune on the bigger upper pulley and the 100 octane for the track with the smaller upper.
^ this is how I have mine setup. one tune 21-22psi 100, one for 18-19 on 93. i have a 4lb lower

i will probably never use the 93 pulley and tune
 

ITLLOWNU

oh hai!
Joined
Jan 1, 2008
Messages
2,164
Reaction score
0
i dont see why people are affraid of more boost on teh pump..

now im at the limit but anything less is not an issue at all

22-23 psi on pump:D 10k miles and 100 or more passes..still kickin ass:headbang: even through the 6-7 straight weeks of 90-100* and very high humidity summer days in Va for 4 yrs

got a 104 tune with more timing but ive never used it:(
 

Flatliner

I'm kind of a big deal...
Joined
Mar 3, 2004
Messages
35,000
Reaction score
0
i dont see why people are affraid of more boost on teh pump..

now im at the limit but anything less is not an issue at all

22-23 psi on pump:D 10k miles and 100 or more passes..still kickin ass:headbang: even through the 6-7 straight weeks of 90-100* and very high humidity summer days in Va for 4 yrs

got a 104 tune with more timing but ive never used it:(
Most tuners won't... because you will get the blame when some yahoo bumps the timing up with the boost but leaves the 93 octane tune. How long would those tuners be in business, think about it? With the interwebz word travels fast that xyz tuning keeps blowing motors up...

that being said, maybe you're right, maybe low timing on high boost is the secret for 93 octane tune, but no one around here has had the cajones to do it :lmao: I'd be curious to run my car against yours at the track and see how they perform on the same day with your 93 low timing and my 100 octane higher timing. 3rd gear will not lie in the 1/4 ;) Do you know how many degrees of timing are in your 93 tune? What's your upper/lower combo? In my experience, warmer days bring lower boost/ heat soak, maybe you've been lucky and in reality the car is not making the boost you think it is and the car is actually pulling timing and you don't realize it. I just don't know if would gamble like that on a cool fall/ winter day around here. Only way to truley know would be to datalog it... I for one, would love too and see what really is going on in there. :biggthump
 

gnxs

Corn-Fed Goodness
Joined
Apr 26, 2004
Messages
8,866
Reaction score
0
I would never suggest to anybody to run pump gas and 20+ psi. Most people don't watch or understand enough about what's going on with their combo/tune to keep their motors alive at those boost levels on pump gas. Too many variables that could result in a fried motor. And I would hardly call 10k miles "longevity" since many people could put that many miles their cars in a year (myself included).

In the limited experience I've seen locally, every car that spun 20+ psi on their twin-screws and lived a long life, enhanced their octane in one way or another (meth, torco, race fuel, etc.). Several people who didn't all wound up doing engine builds. Coincidence....perhaps. :dunno:

Go to ModFords and look through the thread entitled Summary of Blown Engines http://www.modularfords.com/forums/showthread.php?t=12489&highlight=summary+blown&page=31 and draw your own conclusions. A post by Edmisten1 on the last page (page 31) sums up my own feelings on the subject pretty well:

Not to keep kicking a dead horse, but I just went over all 31 pages of this thread and looked at the what octane fuel was being ran at the time of failure.

91 octane: 7 instances (I know...hard to believe someone actually beat on a car like this with 91 octane fuel but it's documented here)
92 octane: 3 instances
93 octane: 32 instances
94 octane: 3 instances
100 octane: 1 instance (BadCobra logged this using 200 shot N20 as well)

Dgussin1 listed 17-18 psi street tune w/ 91 octane and 18* advance; 19-20 psi race tune w/ 100 octane and 20+* advance; he does not mention what tuneup he was running when it let go.

Although I did not count psi or timing advance at time of failure, just glacing at it, it's clear 15-16 psi with 19* timing advance is probaby a fair average. IMO, well above the reasonable limitations of what unleaded pump gas is capable of sustaining.

On page 23, ITSTOCK says "The way to avoid catastrophe is by using the right octane and not doing 170 mph top end runs".

What else really needs to be said? Upwards of 20 lbs of boost with a PD blower that creates a trememdous amount of heat with timing nearing 20* is asking ALOT for unleaded, pump gas...of any octane rating. Of course there are some failures where fuel probably didn't play a part. But at some point, you either build a race car and put race gas in it OR you build a street car and put pump gas in it. IMO and in my experience, you are flirting with disaster when you build a race car and put pump gas in it. Can all these failures be a coincidence? Subjecting these cars to numerous 40-140 highway pulls, 1/4 mile passes and the daily beatings we put them through given the data presented here begs the question: how much can you really expect from pump fuel? I'm not so naieve as to think high dollar, high octane fuel like VP Red, C12, or even C16 will prevent every motor from grenading or holing a piston, but how many would it have saved and how many will it save knowing this....?

Allan,

If I remember correctly from some track visits you posted about last year, you still haven't gotten the current combo to really perform the way it should. If it was me I might work to get all the bugs ironed out before thowing a few more pounds of boost at it. Also, I seem to remember those 2.4 KB's being real "heat pumps" when your really start spinning them hard. SVTDubs blower used to heat soak badly when he really started turning up the boost on it.

Aren't you already running like 20 psi on it?
 

Bob_Kurgan

Flyin_Hawaiin
Joined
Feb 16, 2005
Messages
3,013
Reaction score
0
I would never suggest to anybody to run pump gas and 20+ psi. Most people don't watch or understand enough about what's going on with their combo/tune to keep their motors alive at those boost levels on pump gas. Too many variables that could result in a fried motor. And I would hardly call 10k miles "longevity" since many people could put that many miles their cars in a year (myself included).

In the limited experience I've seen locally, every car that spun 20+ psi on their twin-screws and lived a long life, enhanced their octane in one way or another (meth, torco, race fuel, etc.). Several people who didn't all wound up doing engine builds. Coincidence....perhaps. :dunno:

Allan,

If I remember correctly from some track visits you posted about last year, you still haven't gotten the current combo to really perform the way it should. If it was me I might work to get all the bugs ironed out before thowing a few more pounds of boost at it. Also, I seem to remember those 2.4 KB's being real "heat pumps" when your really start spinning them hard. SVTDubs blower used to heat soak badly when he really started turning up the boost on it.

Aren't you already running like 20 psi on it?
larry is correct..

while running 20-22psi on pump gas is possible, it requires that i retard the timing so much that its actually not much of an advantage... add to that the INCREASE in IATs and you will have a car that makes more torque down low, but looses a ton up top because of the IAT retarder.. The typical setup 17-18psi is normally good for 580-600rwhp on pump gas and 20-22psi can hit of 630-650 on race gas
 

N20GT

Plz place 3,000 kudos here. kthx
Joined
Sep 6, 2006
Messages
48,400
Reaction score
1,812
Location
Crown point, IN
What's the best track time so far? IRS or solid? More boost may not be the answer.
 
OP
S

sonic02gt

Kona Blue shelby
Joined
Sep 18, 2005
Messages
1,533
Reaction score
0
I would never suggest to anybody to run pump gas and 20+ psi. Most people don't watch or understand enough about what's going on with their combo/tune to keep their motors alive at those boost levels on pump gas. Too many variables that could result in a fried motor. And I would hardly call 10k miles "longevity" since many people could put that many miles their cars in a year (myself included).

In the limited experience I've seen locally, every car that spun 20+ psi on their twin-screws and lived a long life, enhanced their octane in one way or another (meth, torco, race fuel, etc.). Several people who didn't all wound up doing engine builds. Coincidence....perhaps. :dunno:

Go to ModFords and look through the thread entitled Summary of Blown Engines http://www.modularfords.com/forums/showthread.php?t=12489&highlight=summary+blown&page=31 and draw your own conclusions. A post by Edmisten1 on the last page (page 31) sums up my own feelings on the subject pretty well:

Not to keep kicking a dead horse, but I just went over all 31 pages of this thread and looked at the what octane fuel was being ran at the time of failure.

91 octane: 7 instances (I know...hard to believe someone actually beat on a car like this with 91 octane fuel but it's documented here)
92 octane: 3 instances
93 octane: 32 instances
94 octane: 3 instances
100 octane: 1 instance (BadCobra logged this using 200 shot N20 as well)

Dgussin1 listed 17-18 psi street tune w/ 91 octane and 18* advance; 19-20 psi race tune w/ 100 octane and 20+* advance; he does not mention what tuneup he was running when it let go.

Although I did not count psi or timing advance at time of failure, just glacing at it, it's clear 15-16 psi with 19* timing advance is probaby a fair average. IMO, well above the reasonable limitations of what unleaded pump gas is capable of sustaining.

On page 23, ITSTOCK says "The way to avoid catastrophe is by using the right octane and not doing 170 mph top end runs".

What else really needs to be said? Upwards of 20 lbs of boost with a PD blower that creates a trememdous amount of heat with timing nearing 20* is asking ALOT for unleaded, pump gas...of any octane rating. Of course there are some failures where fuel probably didn't play a part. But at some point, you either build a race car and put race gas in it OR you build a street car and put pump gas in it. IMO and in my experience, you are flirting with disaster when you build a race car and put pump gas in it. Can all these failures be a coincidence? Subjecting these cars to numerous 40-140 highway pulls, 1/4 mile passes and the daily beatings we put them through given the data presented here begs the question: how much can you really expect from pump fuel? I'm not so naieve as to think high dollar, high octane fuel like VP Red, C12, or even C16 will prevent every motor from grenading or holing a piston, but how many would it have saved and how many will it save knowing this....?

Allan,

If I remember correctly from some track visits you posted about last year, you still haven't gotten the current combo to really perform the way it should. If it was me I might work to get all the bugs ironed out before thowing a few more pounds of boost at it. Also, I seem to remember those 2.4 KB's being real "heat pumps" when your really start spinning them hard. SVTDubs blower used to heat soak badly when he really started turning up the boost on it.

Aren't you already running like 20 psi on it?
I have 17 psi now . There were alot of bugs in the car with either alot of belt slip issues or blower problems. I got all belt slip issues resolved and had blower sent off to kennie bell for complete rebuild. Had new 02s sensors installed new aux idler custom bracket from deans performance fixed belt problem. Kennie bell found blower needed new seals and front drive rebuilt thats what i get from buying a used blower. And when car was tuned had 1 good o2 sensor and belt slip issues and a leaking kennie bell. So now car after 4lb lower should get a nice retune. I Shouldnt have any other issues besides the IRS hopping around at the track :D
 

blck10th

Well-known member
Joined
Jan 11, 2007
Messages
17,963
Reaction score
9
I have 17 psi now . There were alot of bugs in the car with either alot of belt slip issues or blower problems. I got all belt slip issues resolved and had blower sent off to kennie bell for complete rebuild. Had new 02s sensors installed new aux idler custom bracket from deans performance fixed belt problem. Kennie bell found blower needed new seals and front drive rebuilt thats what i get from buying a used blower. And when car was tuned had 1 good o2 sensor and belt slip issues and a leaking kennie bell. So now car after 4lb lower should get a nice retune. I Shouldnt have any other issues besides the IRS hopping around at the track :D

Just get 28" slicks. it won't hop around. I want to get some 26's this year and try it and mph better
 

ITLLOWNU

oh hai!
Joined
Jan 1, 2008
Messages
2,164
Reaction score
0
Most tuners won't... because you will get the blame when some yahoo bumps the timing up with the boost but leaves the 93 octane tune. How long would those tuners be in business, think about it? With the interwebz word travels fast that xyz tuning keeps blowing motors up...

that being said, maybe you're right, maybe low timing on high boost is the secret for 93 octane tune, but no one around here has had the cajones to do it :lmao: I'd be curious to run my car against yours at the track and see how they perform on the same day with your 93 low timing and my 100 octane higher timing. 3rd gear will not lie in the 1/4 ;) Do you know how many degrees of timing are in your 93 tune? What's your upper/lower combo? In my experience, warmer days bring lower boost/ heat soak, maybe you've been lucky and in reality the car is not making the boost you think it is and the car is actually pulling timing and you don't realize it. I just don't know if would gamble like that on a cool fall/ winter day around here. Only way to truley know would be to datalog it... I for one, would love too and see what really is going on in there. :biggthump
yeah i totally understand the tuners liabitlity and my man Chris doesnt tune that way either. but for a select few guys who understand the risks and wouldnt pass blame , he tuned them to the edge, but just this side of it:DAll of our cars are still going strong.


I have gone 10.50 @ 136 and hot lapped a 10.57 @ 138 on pump gas 93 with about 5 mins. between the two passes. It was 89 deg that day and were the last two passes the car ever made.

My timing is at 17.5* and peak boost when the car was tuned was 23.75 psi. It held a consistant upper 22 through 23+ psi throughout the pull. It was 88 deg outside with about 45% humidity during the tuning. On the street i see 22 on the guage when its hot and almost 24 when its cold.

I had a 6lb lower and a 3.5 upper making 19 psi and it dynoed 611 whp /585 wtq ,then i switched to a 3.2 upper and saw 22-23 psi and made 634 /636 on pump. I also had 28" tires on at that time too..i dont think they hurt tq numbers but i have heard it will rob 10 or so hp. I cant honestly say if a taller tire hurts a dyno run but thats what it made on the big tire.


We datalogged the car at the track to make sure we werent getting too high of IATs and pulling timing and all was good. If it wasnt chris would have made me back the boost down.

Two guys i always raced wth had the exact to the t same setups as my current one and made pretty much identical numbers on pump, and on race gas they both dynoed in the 650s for rwhp and in the 660s for tq. So id imagine if i dynoed the race tune it would be right there as well.They both drove their cars alot more than me all summer long and beat the hell out of them with no issues ever:dunno:

maybe were just lucky:lmao: or chris really does know what hes doing

ive played with it on the street with race gas and i can definately feel the difference so it wouldnt supprise me if it put down in the 650 range

Again i wouldnt recomend running what i do but 19-20 on 93 i dont see an issue with and if the tune is right it can be fine and lots of people run it.

but making in the 580s -590s and going to almost 640 is a big gain but has risks that i fully understand:biggthump

But it runs great , the plugs always look good and ive never heard any pinging so far.LOL event this past summer at the picnic..it was hot as fuck and me and Jon went out and beat on her for a while..

i cant wait to get back to the track..its been over 2 yrs now:-o
 

gnxs

Corn-Fed Goodness
Joined
Apr 26, 2004
Messages
8,866
Reaction score
0
I have 17 psi now . There were alot of bugs in the car with either alot of belt slip issues or blower problems. I got all belt slip issues resolved and had blower sent off to kennie bell for complete rebuild. Had new 02s sensors installed new aux idler custom bracket from deans performance fixed belt problem. Kennie bell found blower needed new seals and front drive rebuilt thats what i get from buying a used blower. And when car was tuned had 1 good o2 sensor and belt slip issues and a leaking kennie bell. So now car after 4lb lower should get a nice retune. I Shouldnt have any other issues besides the IRS hopping around at the track :D
Good to hear....sounds like you certainly had a bunch of issues holding you back before that you've rectified.

You add another 4 psi and I would certainly get it tuned for 100 octane fuel at that boost level (21psi) if it was me. Yea the price difference is pretty substantial if you drive alot at high boost, but 5+ years with a twin-screw, 300+ passes and 110,000+ miles on the factory longblock tells me I went the proper route. Maybe it'll live on 93 octane, but you'd be leaving yourself ZERO margin for error.

My $0.02.
 

ITSQUIK

Big Trouble in Little China
Joined
Apr 6, 2005
Messages
2,606
Reaction score
3
Listen little brother.....Forget about more boost. You dont need it.

Now that you have all the bugs figured out JUST learn to master what you have. Your car needs nothing now other than for you to take it to the track and PRACTICE, PRACTICE, PRACTICE!!

After you master what you have THEN worry about adding more boost.

:biggthump
 

FuelSlut

FK RED STAR
Joined
Nov 9, 2005
Messages
1,969
Reaction score
0
Listen little brother.....Forget about more boost. You dont need it.

Now that you have all the bugs figured out JUST learn to master what you have. Your car needs nothing now other than for you to take it to the track and PRACTICE, PRACTICE, PRACTICE!!

After you master what you have THEN worry about adding more boost.

:biggthump
that car is going noplace with that stock IRS. You need urithane bushings real slicks and maybe toe link bars along with a good IRS brace and then you can try the 1/4!

With 572 rwhp @17 psi I was layin down consistant 11.40's then I upped the boost to 21psi made 614 to the tire, on one bad ass 100 tune from mr Kurgan and 2 broken halfshafts and one melted clutch later I never came close to matching my previous time granted my mph skyrocketed to 128 but what's the point???? All this I tried on stock IRS!

Do it right learn from our mistakes. Just ask. Good luck.
 

BlaqSnake

PC Pimp
Joined
May 13, 2006
Messages
5,328
Reaction score
2
Location
Aurora, IL
Listen little brother.....Forget about more boost. You dont need it.

Now that you have all the bugs figured out JUST learn to master what you have. Your car needs nothing now other than for you to take it to the track and PRACTICE, PRACTICE, PRACTICE!!

After you master what you have THEN worry about adding more boost.

:biggthump

Good Call! :headbang:
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Top Bottom