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Discussion Starter #1
Hello,
I have a new KB 2.2 w/Flowzilla/Blowzilla that will be going on a stock, low mile 88 Mustang 5.0.
I plan on adding a set of AFR165 heads to take advantage of lower weight, better air flow and combustion cooling so I can add more boost.

I also plan on building an a2a so I can add more boost while using only pump gas.

How many pounds of boost have you been able to run on 92 octane pump gas and what compression ratio are you running?

Thanks for your input.
Ken
 

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Discussion Starter #2
A little more info:
This engine will be going into a 68 Fastback with T56, Global West Suspension and 9" rear.

The car will spend most, if not all of its time on the street and will see some long road trips.

My goals are
1) 20+ mpg when driven sanely (reason for stock cam and 6 speed)
2) Running 92 octane. (Reason for a2a)
3) Mid-low 12s in the qtr. (use blower for the power, not big heads and cam)
4) Very streetable in traffic and in town. (No overheating or lurching while idling in gear)
5) Able to cruise at Freeway speeds below 1500 rpm (reason for small port and valve AFR heads)

Want high enough compression to get good mpg, but not so high that I'm unable to go over 8 psi on pump gas.

If I could run the motor above on pump gas and safely see 12 psi, I would be very happy.

My big question is, is it possible if I build an a2a setup for this engine?

Thanks again
Ken
 

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Sure it is possible. The ignition timing will determine how much power the car will make for any given amount of boost on pump gas. The engine may make the same power at 9 psi as it does at 12 psi if you have to pull a lot more timing to keep it out of detonation at 12 psi. Or it may take 12 psi with no issues. A lot depends on the efficiency of the A/A intercooler. I think that 165 heads are too small, a 185 head will make more power without any of the issues you stated. As far as compression, I would shoot for 9.0:1
 

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Discussion Starter #4
Sure it is possible. The ignition timing will determine how much power the car will make for any given amount of boost on pump gas. The engine may make the same power at 9 psi as it does at 12 psi if you have to pull a lot more timing to keep it out of detonation at 12 psi. Or it may take 12 psi with no issues. A lot depends on the efficiency of the A/A intercooler. I think that 165 heads are too small, a 185 head will make more power without any of the issues you stated. As far as compression, I would shoot for 9.0:1
Thank you for your help and you make a good point on timing vs boost.
I have a good stock, low mile engine that I will be using, so the only control I will have for compression is the combustion chamber size and it appears that the AFR185 would be the only one that would give me a choice.

The reason I was thinking about the AFR165 was that the smaller valves and ports would give me good velocity when I'm cruising and not under boost, which I'm thinking would give me better mpg on long trips.

I'm also thinking that a smaller combustion chamber (which I can get on both heads) would give me better mpg, but I could be wrong on that line of reasoning.

How is the port velocity on a 302ci engine with AFR185 heads when not under boost? Maybe a better question would be, how would the 185s be on a stock 302 with a stock or mild cam? Would it bog at low rpm's?

Thank you again for your help?
Ken
 

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Port velocity is a non issue with a KB supercharger, any load on the engine produces boost. Port velocity is negligible at idle or cruise/off idle. Low rpm load on a N/A engine would make port velocity important for throttle response, but with instant boost on tap it becomes a non issue. Consider the 1969/70 Boss 302, it had cylinder heads with 2.25" intake valves and huge intake ports. It did not bog at low rpm's, it did not have a ton of torque, but the driveability was fine.
 

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Discussion Starter #6
Port velocity is a non issue with a KB supercharger, any load on the engine produces boost. Port velocity is negligible at idle or cruise/off idle. Low rpm load on a N/A engine would make port velocity important for throttle response, but with instant boost on tap it becomes a non issue. Consider the 1969/70 Boss 302, it had cylinder heads with 2.25" intake valves and huge intake ports. It did not bog at low rpm's, it did not have a ton of torque, but the driveability was fine.
Thanks again for your help.

With 3:50 gears I should be able to cruise on the freeway in the area of 1300 rpm in 6th gear.

Using AFR 185 with a stock or very mild cam and ported 94 Cobra lower, what do you think my chances of getting over 20 mpg if I'm not getting into the boost?
Guessing car weight will be in the area of 3200-3300 pounds.

First and foremost, the car is a street car that will be driven on some long trips and will be lucky to see 5 minutes of full throttle time a year. Since the car suspension is more suited to cornering and considering that a 10" tire is about the limit inside the rear fender, I'm guessing that part throttle boost will boil the tires.

Since 92 octane (or lower) pump gas is a requirement, I'm giving serious consideration to building an a2a system.

I expect low mpg when I'm driving under boost, but want decent mpg when I'm not driving under boost.
I love the 70's big block power, but also want decent small block mpg.

Looking at today's cars is amazing to me. In the 60's & 70's you got 6-10 mpg out of an 11 second car. Today an 11 second car gets better mpg than an old 40HP Volkswagen.

Thanks again for your help.
Ken
 

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Discussion Starter #7
Just noticed that you are in Maple Valley.
I live in Eatonville, about 30 minutes South of Puyallup.

How often do you race at PIR? (still SIR to me) I'd love to check out your car.
 

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20's mpg is possible depending on a number of conditions. Sometimes having the S/C helps mpg as the engine sees less throttle opening during lighter load application compared to an N/A set up. The KB is a very free spinning S/C when not under load, so outside of the added weight of the S/C and supporting components it should not have a net negative effect on MPG.
I only get out to Pacific Raceways a few times a year as their weekend schedule is dominated by road race events. They are open on Fri nights for drags but I rarely have the time to get out there after work and such. I will be going out to Bremerton this coming weekend and then the last weekend of the month is a Heads Up event down in Woodburn Oregon that I will be going to, that is a Fri/Sat/Sun event. Will be there all 3 days.
 

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Discussion Starter #9
20's mpg is possible depending on a number of conditions. Sometimes having the S/C helps mpg as the engine sees less throttle opening during lighter load application compared to an N/A set up. The KB is a very free spinning S/C when not under load, so outside of the added weight of the S/C and supporting components it should not have a net negative effect on MPG.
I only get out to Pacific Raceways a few times a year as their weekend schedule is dominated by road race events. They are open on Fri nights for drags but I rarely have the time to get out there after work and such. I will be going out to Bremerton this coming weekend and then the last weekend of the month is a Heads Up event down in Woodburn Oregon that I will be going to, that is a Fri/Sat/Sun event. Will be there all 3 days.
I have a friend that usually does Woodburn with a 9 second pickup. I'll need to see if he's going this year. I'd love to see you run.

So how do you feel about the 185 combustion chamber size?

They offer 58cc and 72cc and obviously the 72cc would lower the compression allowing more boost or timing, but wouldn't the lower compression cost me some mpg when I'm just cruising down the freeway?

Also, I don't know that I would put much faith in this, but somewhere I read that the AFR 58cc head is more efficient than the 72cc. Hey I read it on the intranet so it has to be true, right?:grin2:

My guessOmeter says that 72cc would put me in the range of 8.5:1 and 58cc just shy of 10.0:1 compression.

VALVES:
My engine is a stock low mile 88 GT.
I haven't pulled the heads and when I do, if the pistons look good and there is good cross hatch, I plan on running the short block the way it is. I will need to change to a front sump pan so I may pop a couple rod and main caps to see what the bearings look like.

So, considering that the 185 has larger valves, it looks like I will be limited to stock or close to stock cams and throwing away a lot of flow.
Will that be a problem?

I have never used or seen one used, but I know that they sell a cutter that looks like a valve for cutting valve reliefs in the piston and while the heads are off, maybe it would be wise to cut reliefs in case at some future date wanting to go with a cam with more lift and faster ramp rates.
It seems to me that in order to use a tool like this, I would need to disassemble one of my brand new heads and use it for a guide. That doesn't sound good to me. Also, wouldn't this effect the engine balance, not to mention the chance of metal dust getting into the engine?

Thanks again for your help.
Ken
 

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If you stay with a camshaft in the 114 to 115 LSA area then the amount of lift with larger valves is moot. It is the duration (amount of time the valve is open) that causes PTV issues, not lift. Plus a 114-155 LSA is very boost friendly. The engine in the racecar has a camshaft with over .700 lift on a 115 LSA and it makes pretty good power, just over 3.3 HP per cubic inch.
I would run the 72cc head simply because the 2.2 KB is capable of around 18 psi on a 302, so you could always run more than 12 psi>:)>:)
 

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Discussion Starter #11
If you stay with a camshaft in the 114 to 115 LSA area then the amount of lift with larger valves is moot. It is the duration (amount of time the valve is open) that causes PTV issues, not lift. Plus a 114-155 LSA is very boost friendly. The engine in the racecar has a camshaft with over .700 lift on a 115 LSA and it makes pretty good power, just over 3.3 HP per cubic inch.
I would run the 72cc head simply because the 2.2 KB is capable of around 18 psi on a 302, so you could always run more than 12 psi>:)>:)
The largest off the shelf, Comp Cam Blower cam, is the Blower 284HR 114 LSA, 224 & 230 @ .050, .533 & .544
Do you believe that the AFR 185 valves would clear stock unnotched pistons with this Cam?

If this would clear, then I believe that the smaller cams should have no problem.
 

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Even with a 1.7 ratio rocker arm that cam does not have enough duration to be an issue. Assuming the cam is installed straight up.
 

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Discussion Starter #13
Even with a 1.7 ratio rocker arm that cam does not have enough duration to be an issue. Assuming the cam is installed straight up.
Thank you for your help.
I imagine that I will probably go with a smaller cam, because my goal (at this time) isn't for the most power I can get. My goal is a combination of decent power, economy and dependability similar to what someone that buys a factory supercharged Mustang would expect.
 

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Discussion Starter #15
Other than TB and exhaust, my son bought a stock 94 Cobra yesterday.

The guy he bought it from had a lot of high performance parts and as part of the deal, he gave my son a set of AFR 165 heads and a set of new ARP head and main studs.

I had loaned my son some money and in appreciation he gave me the heads and studs that he has no plans of using.

Looks like I now have a free set of AFR heads.
Not as big as I would have liked, but I'm not going to look a gift horse in the mouth.

After this thread, I'm convinced on the merits of the 185's, but for little more than the cost of some good head gaskets, I could at least try the 165's and see how well I like them.

I do wonder if I should get the exhaust ported or just leave everything alone and see if I like or hate the results.
 

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Leave the exhaust alone, as cast for that head, and for what you are doing it is fine.
 

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Other than TB and exhaust, my son bought a stock 94 Cobra yesterday.

The guy he bought it from had a lot of high performance parts and as part of the deal, he gave my son a set of AFR 165 heads and a set of new ARP head and main studs.

I had loaned my son some money and in appreciation he gave me the heads and studs that he has no plans of using.

Looks like I now have a free set of AFR heads.
Not as big as I would have liked, but I'm not going to look a gift horse in the mouth.

After this thread, I'm convinced on the merits of the 185's, but for little more than the cost of some good head gaskets, I could at least try the 165's and see how well I like them.

I do wonder if I should get the exhaust ported or just leave everything alone and see if I like or hate the results.
IMO, a KB 2.2 along with a decent cam and AFR 165 heads could put you well up near stock block splitting power. I don't think you need to do any porting anywhere except maybe the lower intake manifold if you really want to. I'm running 11psi on 92 octane. The real trick for you will be in how you tune the car. Where in WA are you? I'm in Spokane.
 

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Discussion Starter #18
IMO, a KB 2.2 along with a decent cam and AFR 165 heads could put you well up near stock block splitting power. I don't think you need to do any porting anywhere except maybe the lower intake manifold if you really want to. I'm running 11psi on 92 octane. The real trick for you will be in how you tune the car. Where in WA are you? I'm in Spokane.
Thank you for your help.

What size KB are you running?

Are you using AFR 165 heads?

What compression ratio are you running and are you using water injection to cool the charge?

Since this is going into a 68 Fastback that I am only willing to mini tub, it appears that the widest tire I can fit inside the rear fenders is 10" and that won't give me much side clearance. Since my suspension it more for handling and less for straight lines, I may go with 9" wide for a little more clearance.

Not sure how much a 9"-10" handling radial tire will take before going up in smoke, but I'm guessing even with the 165 heads, 3rd gear will probably be challenged to hook up if I were to go full throttle.

I live 30 minutes south of Puyallup and 40 minutes S.E. of Tacoma.

I have no ECU or harness and really don't want to mess with trailering the car for exhaust and a tune, so I am really giving a lot of consideration to a new self tuning Engine Management system.

I've tuned a lot of carbed engines, but never used a laptop to tune a car. I'm sure that the learning curve has improved from the 80's&90s, but I have no idea if it has improved to the point where I would want to buy an A9L and piggyback something to it. I sure don't want to melt a piston.

Thanks again for your help.
 

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Discussion Starter #19
I just had a chance to check the heads out a little better.
They need to be cleaned, but the treads appear to be intact.

My only concern is at 7 o'clock on the left cylinder.
There is a minor scratch near the combustion chamber that can barely be felt and then a much more noticeable circular scratch/gouge that appears to be .002"-.003" deep.

I sure hate to think about surfacing the head and losing more cc's off the combustion chamber.

I may try hitting the surface with an Arkansas flat stone and see how it feels then.

How good are the new super charger safe head gaskets at sealing scratches
Like these?
 

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I can not see in the picture what you are talking about. That being said, on average for every .010 the head is surfaced you will lose approximately 1cc of combustion chamber volume. One can easily make this up with a thicker head gasket. Chances are, a resurface of .005 or so will clean up any imperfections in the surface.
 
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