Carb Tuning Issues 383 w/ 670 Holley Street Avenger
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post #1 of 10 (permalink) Old 06-24-2009, 03:38 AM Thread Starter
kpswalin
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Location: Albuquerque, NM
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Compcams XE284H-10 + Matching intake
I don't mean to beat a dead horse, and I know this question has been asked a thousand times in different ways, so I will try to be very specific. I have a 351W .030 over so it will be a 357. I am planning 9.72:1 compression with AFR185cc street heads w/o EGR. The cam I purchased is the XE284H-10 which has the following specs:
RPM Range 2300-6500
Valve Timing .006
Lobe Center 110
Intake Center line 106
Duration 284I / 296E
Duration @ .050 240I / 246E
Valve Lift .541I / .544E
IVO/IVC 34/69
EVO/EVC 80/35
So the part I have been struggling with, is that I have heard some folks experience low RPM problems with the Vic Jr or Super Vic manifolds, and I am afraid of choking my cam with the RPM Air Gap. It has 70 degrees of overlap which seems like a lot to me. Now I know I may not see a lot of time @ 6500 RPM, and if you can't tell, I do not yet own my kit, nor have I driven one. I am trying to make rational decisions about part selection, based on what specifications I have like, vehicle weight, current parts, and desired HP range, etc. I would imagine, as light as these cars are that 428 FWTQ (w/18% loss that puts me @ 350 RWTQ) is plenty and that higher HP numbers are better, but again, I am not a total gear head. That is where the dual plane puts me, and the single plane raises HP a lot (+30) with out lowering torque too much (-10). (Based on compcam's camquest 6 program).
I am not building a race car, but I do not want to be disappointed! I will probably autocross and street drive the car to start with. Based on all the gear ratios I have planned, I am expecting highway cruise @ 65 to be about 2277 RPM.
Can someone with experience give me some rational advice
to help me decide which manifold might be good.
Can a difference between a 1500-6500 manifold to a 3000-7000 manifold really be that noticeable?
What other good options are there for the 351W intake manifold, besides the two mentioned above?
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post #2 of 10 (permalink) Old 06-24-2009, 03:45 AM
2FAST4U
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You really don't want a Victor Jr. or Super Victor with that cam. You will have low rpm driveability issues. The long runners are designed for high velocity at high rpm's such as NASCAR engines. I believe the Torker II low rise single plane manifold (2500-6500 rpm) is more suitable with that cam
Bill D
FFR 3378 - 503 BB, $old and missed
RCR GT40 - 1051P clone, $old
FFR 7991 - becoming a 289 FIA with a Mr. Bruce body, 331, Webers, T-5, IRS, Vintage Wheels pin drive wheels, and Goodyear billboards
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post #3 of 10 (permalink) Old 06-24-2009, 05:36 PM
canuck1
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I won't make a suggestion based on what I don't know, but I have a larger displacement engine and less cam.
My cam has only 230/236 duration, slightly more lift (110 LSA) and I do not make 11 inches of engine vacuum. This can effect your ability to use vacuum assisted power brakes among other issues.
Shoot your question to Gordon Levy in the "Ask the Expert" section. He'll give you sound advice and he's a Comp Cams dealer as well.
Sean
MK 3.5 (MK IV body retrofit to MK III chassis)(, 351W stroked & poked to 396 c.i., custom EFI, 4 into 4's, 3link, 3.73, 15" Halibrand replicas, full bumpers, 2 X roll bars, I² electronics, hydroboost, 5-lug, GT front, MK VIII/Cobra rear discs, painted by SRP (again!)
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post #4 of 10 (permalink) Old 06-24-2009, 08:05 PM Thread Starter
kpswalin
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Thanks 2FAST4U, the Torker II seems like it might a really good compromise for my engine.
Thanks canuck1, I put a question to Gordon on the following thread:
HTML Code:
http://www.ffcars.com/forums/showthread.php?t=221625
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post #5 of 10 (permalink) Old 06-25-2009, 02:42 AM Thread Starter
kpswalin
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Gordon states he would run the Vic Jr. Is anyone running this combination or similar, and NOT happy?
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post #6 of 10 (permalink) Old 06-26-2009, 02:10 PM
richard nyberg
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Only my opinion. The torker 2 is a huge compromise. Those intakes were around in the 70s. Compared to what is out there it could rob you of huge HP. I wouldnt use one unless there were hood clearance issues that couldnt be fixed otherwise. They are popular only in that they are short in height. I raised the nose bubble on my coupe to avoid using one. If you already have the 185 AFR heads then plan your build to match them from aircleaner to headers. The 185s arent too aggressive and very streetable and an RPM air gap or similar would work well. Think of it as a hose that is flowing H2O big hose to small and back isnt compatible. Big airflow equals HP but sacrifices drivability at lower RPM. If you have the heads and the cam doesnt work with it toss the cam. AFR might have recommendations on cam for the heads???? Your system should be matched across the board. Ask me because I have gone too big of cam...too big carb...all of the above. In the early days I put a 750 DP on my more or less stock 327 in a 69 Camaro... and spent a ton of effort trying to get it to work. Good luck, the possibilities are endless.
" Resistance is futile"
Coupe, 392 Ford racing Z head 392, FAST EZ EFI, Tremec, Levy 5 link and 8.8 with 3.73, P/B, P/S, A/C.
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post #7 of 10 (permalink) Old 06-26-2009, 04:22 PM Thread Starter
kpswalin
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I will probably give the AFR guys a call to see what there thoughts are. I have not yet purchased the heads, and only have the cam and block at this point. I understand that there aren't any heads better than an AFR or TF though for SBF. If I do go with the Air Gap, what role does a spacer play in that manifold?
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post #8 of 10 (permalink) Old 06-26-2009, 05:35 PM
edhunter
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My engine - 351 (+30), AFR 185's, RPM airgap, Mighty demon 650, cam is older compcams 280H w/ flat tappet lifter... works very well for a street car, has been on the road course a time or two... Wouldn't mind a bit more aggressive sounding cam, but the combo works well...
ed
MkIII, 351W with all the fixin\'s...
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post #9 of 10 (permalink) Old 06-27-2009, 02:45 PM
Pman1961
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I agree with Richard Nyberg comments. I've used a Torker II in the past and it was a poor performing manifold. I have a 351w 385hp Ford Crate Motor in my Cobra that came with a Victor Jr style intake and I've purchased an Air-Gap to replace it. The GT40 heads flow a lot less than the AFR's but I feel up to the 185's I would use the Air Gap. If you had a stroker motor with bigger heads then I would consider using single plane Victor Jr. For street driving your Cobra with an occasional Autocross stick with the dual plane intake. I would also tone your cam down. I love a hard hitting motor but typically when shifting gears in traffic your shifting at low rpm's say 2500. If the cam you select does not begin to perform until 2500 rpm the motor will feel like a dog. Build for torque my recommendation. Good luck!
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post #10 of 10 (permalink) Old 07-16-2009, 11:16 PM
Jesse@Fortes
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I would use the victor jr and it will probably want a decent spacer, locking out the timing will help alot of the lower speed issues you will have, but in a light cobra with some gear it probably wont be too big of a deal. maybe a pita for a daily driver. Torker II=junk btw
id use the performer rpm before that...
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FFCars.com : Factory Five Racing Discussion Forum > General Topics > Ford Small Block Engine > Compcams XE284H-10 + Matching intake
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post #1 of 10 (permalink) Old 06-24-2009, 03:38 AM Thread Starter
kpswalin
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Join Date: Feb 2008
Location: Albuquerque, NM
Posts: 71
Compcams XE284H-10 + Matching intake
I don't mean to beat a dead horse, and I know this question has been asked a thousand times in different ways, so I will try to be very specific. I have a 351W .030 over so it will be a 357. I am planning 9.72:1 compression with AFR185cc street heads w/o EGR. The cam I purchased is the XE284H-10 which has the following specs:
RPM Range 2300-6500
Valve Timing .006
Lobe Center 110
Intake Center line 106
Duration 284I / 296E
Duration @ .050 240I / 246E
Valve Lift .541I / .544E
IVO/IVC 34/69
EVO/EVC 80/35
So the part I have been struggling with, is that I have heard some folks experience low RPM problems with the Vic Jr or Super Vic manifolds, and I am afraid of choking my cam with the RPM Air Gap. It has 70 degrees of overlap which seems like a lot to me. Now I know I may not see a lot of time @ 6500 RPM, and if you can't tell, I do not yet own my kit, nor have I driven one. I am trying to make rational decisions about part selection, based on what specifications I have like, vehicle weight, current parts, and desired HP range, etc. I would imagine, as light as these cars are that 428 FWTQ (w/18% loss that puts me @ 350 RWTQ) is plenty and that higher HP numbers are better, but again, I am not a total gear head. That is where the dual plane puts me, and the single plane raises HP a lot (+30) with out lowering torque too much (-10). (Based on compcam's camquest 6 program).
I am not building a race car, but I do not want to be disappointed! I will probably autocross and street drive the car to start with. Based on all the gear ratios I have planned, I am expecting highway cruise @ 65 to be about 2277 RPM.
Can someone with experience give me some rational advice
to help me decide which manifold might be good.Can a difference between a 1500-6500 manifold to a 3000-7000 manifold really be that noticeable?
What other good options are there for the 351W intake manifold, besides the two mentioned above?
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post #2 of 10 (permalink) Old 06-24-2009, 03:45 AM
2FAST4U
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You really don't want a Victor Jr. or Super Victor with that cam. You will have low rpm driveability issues. The long runners are designed for high velocity at high rpm's such as NASCAR engines. I believe the Torker II low rise single plane manifold (2500-6500 rpm) is more suitable with that cam
Bill D
FFR 3378 - 503 BB, $old and missed
RCR GT40 - 1051P clone, $old
FFR 7991 - becoming a 289 FIA with a Mr. Bruce body, 331, Webers, T-5, IRS, Vintage Wheels pin drive wheels, and Goodyear billboards
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post #3 of 10 (permalink) Old 06-24-2009, 05:36 PM
canuck1
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I won't make a suggestion based on what I don't know, but I have a larger displacement engine and less cam.
My cam has only 230/236 duration, slightly more lift (110 LSA) and I do not make 11 inches of engine vacuum. This can effect your ability to use vacuum assisted power brakes among other issues.
Shoot your question to Gordon Levy in the "Ask the Expert" section. He'll give you sound advice and he's a Comp Cams dealer as well.
Sean
MK 3.5 (MK IV body retrofit to MK III chassis)(, 351W stroked & poked to 396 c.i., custom EFI, 4 into 4's, 3link, 3.73, 15" Halibrand replicas, full bumpers, 2 X roll bars, I² electronics, hydroboost, 5-lug, GT front, MK VIII/Cobra rear discs, painted by SRP (again!)
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post #4 of 10 (permalink) Old 06-24-2009, 08:05 PM Thread Starter
kpswalin
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Location: Albuquerque, NM
Posts: 71
Thanks 2FAST4U, the Torker II seems like it might a really good compromise for my engine.
Thanks canuck1, I put a question to Gordon on the following thread:
HTML Code:
http://www.ffcars.com/forums/showthread.php?t=221625
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post #5 of 10 (permalink) Old 06-25-2009, 02:42 AM Thread Starter
kpswalin
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Gordon states he would run the Vic Jr. Is anyone running this combination or similar, and NOT happy?
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post #6 of 10 (permalink) Old 06-26-2009, 02:10 PM
richard nyberg
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Only my opinion. The torker 2 is a huge compromise. Those intakes were around in the 70s. Compared to what is out there it could rob you of huge HP. I wouldnt use one unless there were hood clearance issues that couldnt be fixed otherwise. They are popular only in that they are short in height. I raised the nose bubble on my coupe to avoid using one. If you already have the 185 AFR heads then plan your build to match them from aircleaner to headers. The 185s arent too aggressive and very streetable and an RPM air gap or similar would work
well. Think of it as a hose that is flowing H2O big hose to small and back isnt compatible. Big airflow equals HP but sacrifices drivability at lower RPM. If you have the heads and the cam doesnt work with it toss the cam. AFR might have recommendations on cam for the heads???? Your system should be matched across the board. Ask me because I have gone too big of cam...too big carb...all of the above. In the early days I put a 750 DP on my more or less stock 327 in a 69 Camaro... and spent a ton of effort trying to get it to work. Good luck, the possibilities are endless." Resistance is futile"
Coupe, 392 Ford racing Z head 392, FAST EZ EFI, Tremec, Levy 5 link and 8.8 with 3.73, P/B, P/S, A/C.
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post #7 of 10 (permalink) Old 06-26-2009, 04:22 PM Thread Starter
kpswalin
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I will probably give the AFR guys a call to see what there thoughts are. I have not yet purchased the heads, and only have the cam and block at this point. I understand that there aren't any heads better than an AFR or TF though for SBF. If I do go with the Air Gap, what role does a spacer play in that manifold?
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post #8 of 10 (permalink) Old 06-26-2009, 05:35 PM
edhunter
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My engine - 351 (+30), AFR 185's, RPM airgap, Mighty demon 650, cam is older compcams 280H w/ flat tappet lifter... works very well for a street car, has been on the road course a time or two... Wouldn't mind a bit more aggressive sounding cam, but the combo works well...
ed
MkIII, 351W with all the fixin\'s...
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post #9 of 10 (permalink) Old 06-27-2009, 02:45 PM
Pman1961
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I agree with Richard Nyberg comments. I've used a Torker II in the past and it was a poor performing manifold. I have a 351w 385hp Ford Crate Motor in my Cobra that came with a Victor Jr style intake and I've purchased an Air-Gap to replace it. The GT40 heads flow a lot less than the AFR's but I feel up to the 185's I would use the Air Gap. If you had a stroker motor with bigger heads then I would consider using single plane Victor Jr. For street driving your Cobra with an occasional Autocross stick with the dual plane intake. I would also tone your cam down. I love a hard hitting motor but typically when shifting gears in traffic your shifting at low rpm's say 2500. If the cam you select does not begin to perform until 2500 rpm the motor will feel like a dog. Build for torque my recommendation. Good luck!
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post #10 of 10 (permalink) Old 07-16-2009, 11:16 PM
Jesse@Fortes
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I would use the victor jr and it will probably want a decent spacer, locking out the timing will help
alot of the lower speed issues you will have, but in a light cobra with some gear it probably wont be too big of a deal. maybe a pita for a daily driver. Torker II=junk btw
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FFCars.com : Factory Five Racing Discussion Forum > General Topics > Ford Small Block Engine > Compcams XE284H-10 + Matching intake
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87vette81big
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If you have your Cam Card the IVO, IVC, EVO, EVC numbers will be on it.
I searched the Net, Only the Ford guys posted thier version of comp cams XE284 H.
Should be real close to SBC.
Numbers exact I did not find on Comp Cams Website.
Its a dated Street strip design cam you have.
Works but not stellar.
Around 70 degrees camshaft overlap.
Its loosely ruled....50 -57degrees overlap gives super smooth idle.
64 degrees is pretty aggressive.
70-75 degrees is HOT.
87-120 degrees cam overlap is Super High RPM Road Race Drag Race Cam.
I searched the Net, Only the Ford guys posted thier version of comp cams XE284 H.
Should be real close to SBC.
Numbers exact I did not find on Comp Cams Website.
Its a dated Street strip design cam you have.
Works but not stellar.
Around 70 degrees camshaft overlap.
Its loosely ruled....50 -57degrees overlap gives super smooth idle.
64 degrees is pretty aggressive.
70-75 degrees is HOT.
87-120 degrees cam overlap is Super High RPM Road Race Drag Race Cam.
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87vette81big
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You need to remove the distributor cap.
Check and see if the mechanical advance weights. Should snap forward in one direction & then return instant by hand.
Then check actual mechanical advance with a timing light.
Time to put what you read in Grumpys Links into practice.
I don't care what the chassis dyno guy did.
He didn't do squat shit.
Check and see if the mechanical advance weights. Should snap forward in one direction & then return instant by hand.
Then check actual mechanical advance with a timing light.
Time to put what you read in Grumpys Links into practice.
I don't care what the chassis dyno guy did.
He didn't do squat shit.
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87vette81big
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The Carburator baseplate mounting gasket. Check it.
Actually remove the gasket.
Should have even clampling witness marks.
Retorque the intake manifold to 30-35 ft/lbs with a decent torque wrench.
Start in the center and work outward torquing down.
Metering blocks on carb to be checked next.
Actually remove the gasket.
Should have even clampling witness marks.
Retorque the intake manifold to 30-35 ft/lbs with a decent torque wrench.
Start in the center and work outward torquing down.
Metering blocks on carb to be checked next.
Theron
Member
I've had that gasket off so many times today that it hurts. The witness marks are nice and even. I've replaced it twice becuase it was getting worn from testing.
Intake is checked. Nothing otu of the ordinary. Followed pattern supplied with intake.
Metering blocks are brand new with the carb, but what would I check on them.
Reminder: This problem exists with two different carbs. One holley 770 and one holley 670. Both were tuned and jetted. The 770 was tuned on the dyno. The 670 I used for testing. The 670 exhibits the same symptoms as the 770.
Intake is checked. Nothing otu of the ordinary. Followed pattern supplied with intake.
Metering blocks are brand new with the carb, but what would I check on them.
Reminder: This problem exists with two different carbs. One holley 770 and one holley 670. Both were tuned and jetted. The 770 was tuned on the dyno. The 670 I used for testing. The 670 exhibits the same symptoms as the 770.
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87vette81big
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Ok. Abnormal PIA Can not solve issues Grumpy & Myself specialize at.
Post the Holley LIST NUMBERS.
ITS ON THE CHOKE AIRHORN.
VERY SMALL STAMPINGS.
My Holley Street Avenger 770 carb is List Number :80770-1
Post the Holley LIST NUMBERS.
ITS ON THE CHOKE AIRHORN.
VERY SMALL STAMPINGS.
My Holley Street Avenger 770 carb is List Number :80770-1
http://www.compcams.com/Technical/DynoSheets/XE284H-10_001.asp
your cam has significant duration for a street/strip application, but in my opinion, that should not be a problem here in that application.
the Torker II intakes only claim to fame, or even use is its fairly low over all height, allowing more hood clearance, it certainly would not be my choice, as every time I see it tested its costing the owner at least 10-15 hp over an air gap design.
Id select the edelbrock rpm air gap, or a decent high rise single plane IF the hood clearance allows its use. as I find those work rather well
http://garage.grumpysperformance.com/index.php?threads/holley-air-bleed-jets-related.11859/
http://garage.grumpysperformance.co...n-670-holley-street-avenger.12305/#post-60572
if you swapped two different carbs on the same intake, manifold and on the same engine and the problem remained constant its a good indicator the the carbs may not be the source of your problem, while a single plane may have given a bit higher peak hp the average power and torque will usually tend to be better with the dual plane , resulting in a bit faster car
http://www.jegs.com/i/Speedmaster/7...187813799591&gclid=CNLht5rAucwCFQetaQoddKoKbg
IN THIS APPLICATION SECOND CHOICE
http://www.jegs.com/i/Edelbrock/350...189802932311&gclid=CJnSro7CucwCFQyHaQod1ioC7g
IN THIS APPLICATION FIRST CHOICE
your cam has significant duration for a street/strip application, but in my opinion, that should not be a problem here in that application.
the Torker II intakes only claim to fame, or even use is its fairly low over all height, allowing more hood clearance, it certainly would not be my choice, as every time I see it tested its costing the owner at least 10-15 hp over an air gap design.
Id select the edelbrock rpm air gap, or a decent high rise single plane IF the hood clearance allows its use. as I find those work rather well
http://garage.grumpysperformance.com/index.php?threads/holley-air-bleed-jets-related.11859/
http://garage.grumpysperformance.co...n-670-holley-street-avenger.12305/#post-60572
if you swapped two different carbs on the same intake, manifold and on the same engine and the problem remained constant its a good indicator the the carbs may not be the source of your problem, while a single plane may have given a bit higher peak hp the average power and torque will usually tend to be better with the dual plane , resulting in a bit faster car
http://www.jegs.com/i/Speedmaster/7...187813799591&gclid=CNLht5rAucwCFQetaQoddKoKbg
IN THIS APPLICATION SECOND CHOICE
http://www.jegs.com/i/Edelbrock/350...189802932311&gclid=CJnSro7CucwCFQyHaQod1ioC7g
IN THIS APPLICATION FIRST CHOICE
Last edited:
Don't know if this link has been posted and it's certainly not the cheapest method, but there is still good info to be had. There are cheaper data acquisition systems (data loggers) that could be purchased, one to comes to mind is the LM-2.
Good Luck!!!
http://www.innovatemotorsports.com/products/lm2.php
http://garage.grumpysperformance.com/index.php?threads/tuning-a-tbucket-dart-400-cuin-engine.11433/
Good Luck!!!
http://www.innovatemotorsports.com/products/lm2.php
http://garage.grumpysperformance.com/index.php?threads/tuning-a-tbucket-dart-400-cuin-engine.11433/
8
87vette81big
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I gave your Chevy Pickup more thought today.
The Valves may need to be adjusted.
Miss adjusted.
That would cause low idle vacuum issues and driveability issues.
Would not hurt to perform a compression check on all 8 cylinders also.
The Valves may need to be adjusted.
Miss adjusted.
That would cause low idle vacuum issues and driveability issues.
Would not hurt to perform a compression check on all 8 cylinders also.
Theron
Member
The machinist and I checked the valves. All looks good. They are a bit on the 'loose' side (1/4 vs 1/2 turn), but that's how he wants to set them.
Running the RPM Air Gap Intake.
Comp says that my vacuum numbers are in the correct range.
I am going to agree with Holley that I just happen to be running in a 'flaw in carburation' zone where moving between the idle/transition/throttle zone just isn't perfect.
I need to tune the secondaries to open a little sooner, but other than that, the truck is fine above 2000 rpm at this point. Great at cruising speed in 4th gear (50mph plus).
The machinist and one of the local hotrod experts stopped by yesterday and we spent some serious time checking things out. Doesn't seem like there is anything wrong, just seems like a compromise between the performance of a hot cam and the driveability of this particular chassis combo. It lives at part throttle on the road and it lugs below 2k rpm. The whole combo doesn't even start breathing until about 2k rpm... this shouldn't be a surprise that it doesn't flow well at lower engine speeds.
The dieseling at idle shutoff is a still an occasional demon, but I have a few things to try.
Thank you for the help. A lot of things were solved in this process.
Running the RPM Air Gap Intake.
Comp says that my vacuum numbers are in the correct range.
I am going to agree with Holley that I just happen to be running in a 'flaw in carburation' zone where moving between the idle/transition/throttle zone just isn't perfect.
I need to tune the secondaries to open a little sooner, but other than that, the truck is fine above 2000 rpm at this point. Great at cruising speed in 4th gear (50mph plus).
The machinist and one of the local hotrod experts stopped by yesterday and we spent some serious time checking things out. Doesn't seem like there is anything wrong, just seems like a compromise between the performance of a hot cam and the driveability of this particular chassis combo. It lives at part throttle on the road and it lugs below 2k rpm. The whole combo doesn't even start breathing until about 2k rpm... this shouldn't be a surprise that it doesn't flow well at lower engine speeds.
The dieseling at idle shutoff is a still an occasional demon, but I have a few things to try.
Thank you for the help. A lot of things were solved in this process.