Best way to proceed with improving up 427 Windsor street setup

[Ace23]

I wasn't sure exactly where to post this so I will start in the small block section. Having recently purchased my first cobra I am really enjoying it and I can't see myself going to any other toy. I came from an 03 supercharged mustang cobra and the only thing I miss is the throttle response and the feel of the mod motor power. I put a new QF750 carb on my car and had it dyno tuned a few months back. My car runs night and day difference but it is not where I want it to be. I have a KC 427 dart block that I think is in need of a refreshen.....cylinder pressure is down a bit and it didn't do so hot on the dyno. This is not something that is pressing as the car runs great but I just want to start making my plans for the next step. If what I am after is not possible then I will re-evaluate. Hopefully we can have some good info out of this discussion.

1. I hate getting 9-10mpg. It is really not about money so don't bring up the "your not a cobra guy" it is just a pain in the butt. I've got 3:23 rears and a TKO-600. It was 7mpg before I had it retuned. Return on any type of investment is not something I'm chasing....but I do know that fuel injection will improve this.

2. If I was to go the fuel injection route how good can the throttle response and overall driveability be? Can it be similar to a N/A modified LS7 in a Z06? If so what is the fuel injection route that would be needed? I do not want to use one of those wet manifold self tuning carb looking setups that cost $2500 but I also don't want to use anything that is unnecessary. I could care less about how vintage it looks under the hood....I bought the car to drive and I'm looking for the best possible setup for reliability and performance.

3. I really would like to be able to keep a windsor setup as I enjoy the sound and characteristics of having a camshaft and all the lope that accompanies. This is a street car and I have no future plans on tracking it. This is Keith's 585hp option and I dont' think it deviates from their street/strip setup. Based on the current characteristics of the car it doesn't like to be driven below 2000rpms and it doesn't really have a serious seat of the pants feel until about 4000rpm and up. Being a street car I dont' have any pipe dreams of turning 7000rpm but I don't want to lose any top end power.......I actually want some more. I've never had a N/A setup before so I guess I'm just used to the power of a supercharged mod motor. Sounds like if a Windsor can offer what I'm looking for then Brent Lykins is the man to put together a plan.

[DWRAT]

What did your 575hp KC 427ci dyno in at?
As for FI call Bob Reems at Imagine Injection. Imagine Injection Inc. |

[trularin]

If I may, do you want to play with the engine or have someone take it to the level you want?

Tru

[MOTORHEAD]

You're going to have to give more detailed info before anyone can suggest any changes.
whats the mileage on the engine ? What cranking compression numbers are you seeing? What was the dyno HP ? What is your 5th gear ratio?.

[SPF1061]

I know you say you are not interested in racing, but is there a local drag strip you could make a few passes at? 1/4 mile time slips will tell a lot more about where you are in real world performance that dyno slips.

[Ace23]

Originally Posted by DWRAT

What did your 575hp KC 427ci dyno in at?
As for FI call Bob Reems at Imagine Injection. Imagine Injection Inc. |

It was tuned by Wayne Presley of Very Cool Parts. It made 360rwhp and 350rwtq and this was on a Mustang Dyno. Temperatures were in the 80's and this was at an AFR of 12.2. Wayne didn't believe it had the motor I told him it did after a few passes......he said it just didn't feel like it should nor did it have the seat of the pants pull. It has 2" headers and Firefly 2.5 inch side pipes and we took the air filter off to rule that out as well.

Originally Posted by trularin

If I may, do you want to play with the engine or have someone take it to the level you want?

Tru

The only part I would participate in is the pulling and reinstalling the motor. If I went the EFI route down the road I would have a professional involved in the setup and tune. I would be working with a tuner and engine builder to make sure the components were selected correctly so that they would compliment each other.

Originally Posted by MOTORHEAD

You're going to have to give more detailed info before anyone can suggest any changes.
whats the mileage on the engine ? What cranking compression numbers are you seeing? What was the dyno HP ? What is your 5th gear ratio?.

Engine has 12K miles. My cylinder pressures were all between 150-160lb with the majority being around 150lb. It made 360rwhp and 350rwtq on a Mustang Dyno with an AFR of 12.2. I do not know my 5th gear ratio but I believe I was told it does not have the overdrive ratio for 5th gear.

Originally Posted by SPF1061

I know you say you are not interested in racing, but is there a local drag strip you could make a few passes at? 1/4 mile time slips will tell a lot more about where you are in real world performance that dyno slips.

Yes there is a local strip but I wont put the car on it......you do make a very valid point. I have a friend that took his car to Wayne a few weeks after I did but they had a sensor on the dyno go bad and they had to go to another local shop to use their dyno. His car has a Keith Craft 441 or something like that and it was rated at 616hp ect.....he made about 80rwhp more than I did but as I mentioned it was not on the same dyno. He and I need to do some pulls out on the hwy as that would be a pretty good comparison.

[jhv48]

Before you even think about changing to fuel injection, make damn sure your engines internals (cam) will be suitable for FI.

Contact the engine builder and see if it's compatible. If not, then you're in for some expensive changes for the retrofit. Might be better to pull it, sell it and buy a custom engine that better suits your needs.

[Ace23]

Originally Posted by jhv48

Before you even think about changing to fuel injection, make damn sure your engines internals (cam) will be suitable for FI.

Contact the engine builder and see if it's compatible. If not, then you're in for some expensive changes for the retrofit. Might be better to pull it, sell it and buy a custom engine that better suits your needs.

That would be my plan as I mentioned above. I'm aware that the right combination and satisfaction isn't going to be achieved by throwing components around hoping they end up working well together. My goal would be to have my existing motor gone through and make the necessary changes to put me in the direction I want to move in. I will not spend money trying to make something perform in a manner its not capable of. My fear is that I'm going to hear "man get a 385 series big block"

[ffr 1137]

R U absolutely sure it's a 427 stroker? A 351 looks the same from the outside
U know. May have to dig into it some. If Wayne says there's something goofy
goin' on...believe it.

Mike F

[Ace23]

Originally Posted by ffr 1137

R U absolutely sure it's a 427 stroker? A 351 looks the same from the outside
U know. May have to dig into it some. If Wayne says there's something goofy
goin' on...believe it.

Mike F

Mike,
You make a great point but I put my trust in the person that sold me the car and I have all the documentation that supports what I was told. I am confident that the motor combination is what it was advertised to be. Wayne did not inspect the motor and then say hey " this sure doesn't look like what you told me it was".....his opinion was based on the power output and how the car performed on his dyno compared against other 427's and Keith setups. Your point is well taken as I know there are some shady things that take place in the industry but I have no doubts about what I bought. I can say that if you pop the hood or get under the car everything from the outside can be verified against what the build documentation is....dart block, intake, distributor, Brodix heads, custom headers. Aside from some improvements I want to make I absolutely love the car! I can't see how people ever sell these things or don't drive them!

[SPF1061]

The power output does sound way off to me. I had my Roush 427R rebuilt in the past 5000 miles and had it dynoed after the rebuild. I will look when I get home and let you know what those numbers were. Pretty sure it was a Mustang dyno. Keith Kraft and Roush numbers should be in the same general ballpark for a 427 stroker provided Keith's is not a solid lifter race engine.

[Bernica]

I would think that if it's one of KC's engines he can maybe tell you all you need to know about the internals and the build? That would be a good starting point in making a plan. Not sure if KC stamps numbers or has other reference points on his builds to keep track, but it seems worth a phone call.

[SPF1061]

Ace23, I am back home and looked at my files. FWIW, my Roush 427R with a dual plane intake dynoed at @420rwhp on a Mustang and @460rwhp on a Dynojet. This is a motor that Roush rates @540 flywheel hp. This is a stout motor with an AED 750cfm carb, well tuned and runs 11:30s in the quarter mile on a good day. Your 360rwhp number looks very low to me for the motor you have.

[Ace23]

Originally Posted by SPF1061

The power output does sound way off to me. I had my Roush 427R rebuilt in the past 5000 miles and had it dynoed after the rebuild. I will look when I get home and let you know what those numbers were. Pretty sure it was a Mustang dyno. Keith Kraft and Roush numbers should be in the same general ballpark for a 427 stroker provided Keith's is not a solid lifter race engine.

I don't have it in front of me but based on the information I have the camshaft is a Comp Cam hydraulic roller.

Originally Posted by Bernica

I would think that if it's one of KC's engines he can maybe tell you all you need to know about the internals and the build? That would be a good starting point in making a plan. Not sure if KC stamps numbers or has other reference points on his builds to keep track, but it seems worth a phone call.

I've given Keith's shop a call and they were very helpful. I explained the situation and I believe they told me that my cylinder pressure should be between 170-180lb on my engine. I have the original build on the motor and all the information that Keith provided on tolerances, camshaft selection, dyno numbers ect.

Originally Posted by SPF1061

Ace23, I am back home and looked at my files. FWIW, my Roush 427R with a dual plane intake dynoed at @420rwhp on a Mustang and @460rwhp on a Dynojet. This is a motor that Roush rates @540 flywheel hp. This is a stout motor with an AED 750cfm carb, well tuned and runs 11:30s in the quarter mile on a good day. Your 360rwhp number looks very low to me for the motor you have.

Thanks for the information and that is almost identical to what Wayne Presley told me it should make before we strapped it on the dyno..... he said it would make between 405-420HP and probably closer to the 420hp with my single plane intake, camshaft and 2" headers, firefly exhaust. Back in 2009 the car was previously tuned at Dennis Olthoff''s shop in North Carolina and Olthoff's records have it making 450rwhp on their dyno. I will probably run it out to the local shop that has a dyno jet and get a single pull on it just to have a comparions of the dyno jet and another piece of evidence that yes it is down on power lol. Since Wayne has retuned it with the QF750 it runs much better.....no telling where that missing hp is at. I did notice the other night when I fired it up under the gas station canopy I could see what appeared to be faint white smoke.....kinda just makes you wonder where that 50-60rwhp hp went.

[itstock]

So you want a lopey cam, and fuel injection? You need to make sure you are pairing the two items. Most of the aftermarket fuel injection systems are complete crap, and while you might get better mpg's, the reliability is hit or miss, more so with mismatched parts. I was interested in it. Now I'm not.

The C6 Z06 feels (should feel) like a dog compared to any windsor Cobra with a 500+hp engine. They are higher revving engines with not so much low end torque.

My 530+hp engine did 482rwhp on a dynocom (loaded) and 478rwhp on a mustang dyno (again, loaded). You have something seriously wrong with your engine, and more specifics need to be known, especially for RPM. Most of these engines max out in the mid-upper 5000's, NOWHERE near 7000.

I was getting bored with my car so I just put a 175rwhp nitrous shot on it. Interest in the car is back! Quite simply put, it's AWESOME. Before YOu do that, you really need to find out what is wrong with your engine.

[Ace23]

Originally Posted by itstock

So you want a lopey cam, and fuel injection? You need to make sure you are pairing the two items. Most of the aftermarket fuel injection systems are complete crap, and while you might get better mpg's, the reliability is hit or miss, more so with mismatched parts. I was interested in it. Now I'm not.

The C6 Z06 feels (should feel) like a dog compared to any windsor Cobra with a 500+hp engine. They are higher revving engines with not so much low end torque.

My 530+hp engine did 482rwhp on a dynocom (loaded) and 478rwhp on a mustang dyno (again, loaded). You have something seriously wrong with your engine, and more specifics need to be known, especially for RPM. Most of these engines max out in the mid-upper 5000's, NOWHERE near 7000.

I was getting bored with my car so I just put a 175rwhp nitrous shot on it. Interested in the car is back! Quite simply put, it's AWESOME. Before YOu do that, you really need to find out what is wrong with your engine.

My comments about a LS7 where aimed at how docile they are being a FI 427. I'm not making a single move until I have more information but I'm saying I would want to know the options for going to fuel injection while keeping a Windsor setup. From the research I have gathered I would not want to go to one of the self tuning.....weekend warrior install wet manifold FI setups that seems to basically be a fuel injected carb. It seems like the stack injection or port injection setups are more expensive but potentially deliver the best results. My current rpm limit is 6500rpm but I've never shifted it about 6000rpm. My dyno results where showing max power output around 5800rpm. My comment about 7000rpm was that this is a street car and I'm not looking to turn those types of RPM nor want a motor that makes all its power up top. I'm not disputing something is up with the power output but Its yet to be found. I bet that nitrous is insane....its not my thing but it makes some nasty torque. Are you using a progressive system or are you hand cuffing yourself to the steering wheel and just praying?
*Timing-advanced it in between the dyno pulls until it was shown to lose power.
*Air filter removed on dyno- gained a whopping 4hp
*Exhaust setup is 2" headers through 2.5" Firefly stainless side pipes
*Brand new QF 750......when you go full throttle it was visually inspected and it opens all the way up
*Cranks, idles and runs fine and I would get in it and drive 500 miles tomorrow. As mentioned previously I need to get it on the local dyno jet and see what it makes. If it was right I would expect it to make about 450-460rwhp. If it made 360rwhp on a mustang and that dyno was accurate then I expect it to make about 390hp on the dynojet......so lies the magical 60hp that's missing. This isn't rocket science but the first places you look and the initial bases seem to have been covered.

[DAVID GAGNARD]

I'll take a shot at it......

First off I don't think your cold cranking compression numbers are all that bad, cams with a lot of overlap and duration will not show high cranking numbers..and being they are all close together is another good sign.....

A 427 stroker built to making the advertised HP as yours was built to do will have an aggressive cam and will not like to run at low rpms like yours,it will come on in the higher rpm range as yours does......it's the nature of the beast......

Your fuel mileage will depend a lot on how your drive the car,if your easy on the gas pedal you should get better than 9-10 mpg,but if your like most of use and like to get on it and run it up to 4000 to 5000+ rpms shifting,well, 9-10 mpg is all you can expect......

Your low rwhp #'s could also be tied in with your exhaust...I'm not familiar with the type you have,but it has been proven time and time again on here that exhaust/mufflers plays a big role in rwhp, some have reported a proven 100hp loss with certain types of headers/mufflers....
taking off the side pipes/mufflers and running a pull or two without them might tell you a story you will not believe.....

one or two rear wheel dyno pulls is not enough to tune a car,don't know how many pulls you made or what was done,but at least a half day on a rear wheel dyno will get you the most out of your engine....
each engine I have had on a dyno (engine dyno) was the better part of a day..the tuner tried different jettings and different timing settings and overall at least 20 to 30 hp was gained by trying different configurations.....on my last engine,a change of 2 degrees in the timing was good for 12 hp....we went up/down the timing range from 26 total degrees to 34 total at 2 degree increments and there was a 24 hp difference from 30 to 34 degrees....something you would not know unless it was on a dyno...

There are other things besides jetting and timing to take in consideration,air/fuel ratio,volumetric efficiency and a number of other readings to get the most out of what you have......

Unless you go with a "modern" type engine,you will not have a smooth idling,banshee off idle engine, push rod,carbed, stroker motors just don't do that and make 585hp....

You do have a loss of hp somewhere and I think if you can get it figured out and up to where it should be, you'll be more than satisfied with your engine......

good luck with it and keep us posted......

david

[Ace23]

Originally Posted by DAVID GAGNARD

I'll take a shot at it......

First off I don't think your cold cranking compression numbers are all that bad, cams with a lot of overlap and duration will not show high cranking numbers..and being they are all close together is another good sign.....

A 427 stroker built to making the advertised HP as yours was built to do will have an aggressive cam and will not like to run at low rpms like yours,it will come on in the higher rpm range as yours does......it's the nature of the beast......

Your fuel mileage will depend a lot on how your drive the car,if your easy on the gas pedal you should get better than 9-10 mpg,but if your like most of use and like to get on it and run it up to 4000 to 5000+ rpms shifting,well, 9-10 mpg is all you can expect......

Your low rwhp #'s could also be tied in with your exhaust...I'm not familiar with the type you have,but it has been proven time and time again on here that exhaust/mufflers plays a big role in rwhp, some have reported a proven 100hp loss with certain types of headers/mufflers....
taking off the side pipes/mufflers and running a pull or two without them might tell you a story you will not believe.....

one or two rear wheel dyno pulls is not enough to tune a car,don't know how many pulls you made or what was done,but at least a half day on a rear wheel dyno will get you the most out of your engine....
each engine I have had on a dyno (engine dyno) was the better part of a day..the tuner tried different jettings and different timing settings and overall at least 20 to 30 hp was gained by trying different configurations.....on my last engine,a change of 2 degrees in the timing was good for 12 hp....we went up/down the timing range from 26 total degrees to 34 total at 2 degree increments and there was a 24 hp difference from 30 to 34 degrees....something you would not know unless it was on a dyno...

There are other things besides jetting and timing to take in consideration,air/fuel ratio,volumetric efficiency and a number of other readings to get the most out of what you have......

Unless you go with a "modern" type engine,you will not have a smooth idling,banshee off idle engine, push rod,carbed, stroker motors just don't do that and make 585hp....

You do have a loss of hp somewhere and I think if you can get it figured out and up to where it should be, you'll be more than satisfied with your engine......

good luck with it and keep us posted......

david

David
Thanks for your input. When the car was tuned the tuner did exaclty as you described......I would say a good 3-4 hours was spent tweaking the carb and making timing adjustments while on the dyno. I guess I have overlooked the exhaust. I called Firefly and they told me the pipes that were purchased for my car should be 2.5". I guess the only way to tell would be to remove and measure to verify. As you have mentioned there are quite a few stories about the HP gained from removing or swapping exhaust. While I have no reason to doubt the Firefly exhaust is better than the stock exhaust I should still investigate this as a possible issue. Its pretty weird how well the car runs to be down on power. Will keep everyone informed if anything is found that relates to the exhaust. Might need to check the headers and how they mount up to the heads as well. The headers were custom made 2" to fit the Brodix heads back in 2004

[DAVID GAGNARD]

Even with your compression psi being down to what it is,I don't think that would equal to the loss of hp your seeing,just my opinion......

Sounds like your dyno guy tried jetting and timing and got that part optimized to the engine,so taking that out of the picture,it has to be elsewhere......

Not knowing anything about the headers/sidepipes/mufflers other than the diameter,I'm betting there is a big loss there......I'm running 2.5 inch exhaust and 2.5 inch in/out big mufflers on my little 331 stroker and it is in the 400 to 425 hp range.....

Inside those 2.5 inch side pipes are mufflers of some sort ( a lot smaller than 2.5 inches) and I think that is a big "choking" point for a 427 stroker engine......I'm betting taking off the side pipes/mufflers will surprise you....For a 585 hp,427 stroker,I would run nothing smaller than 3.5 side pipes and a free flowing muffler to see optimum power...

Can you post of photo of the side pipes???

David

[Ace23]

Originally Posted by DAVID GAGNARD

Even with your compression psi being down to what it is,I don't think that would equal to the loss of hp your seeing,just my opinion......

Sounds like your dyno guy tried jetting and timing and got that part optimized to the engine,so taking that out of the picture,it has to be elsewhere......

Not knowing anything about the headers/sidepipes/mufflers other than the diameter,I'm betting there is a big loss there......I'm running 2.5 inch exhaust and 2.5 inch in/out big mufflers on my little 331 stroker and it is in the 400 to 425 hp range.....

Inside those 2.5 inch side pipes are mufflers of some sort ( a lot smaller than 2.5 inches) and I think that is a big "choking" point for a 427 stroker engine......I'm betting taking off the side pipes/mufflers will surprise you....For a 585 hp,427 stroker,I would run nothing smaller than 3.5 side pipes and a free flowing muffler to see optimum power...

Can you post of photo of the side pipes???

David

I don't have any pictures but I can take some. As soon as I get it over to my friends house we will pull a side pipe and take measurements just to know 100% what we are dealing with. At this point all I know is that the side pipes are suppose to be 2.5" and they don't use packing but instead a internal louver or baffle. The brand is Firefly....they sound pretty good but not too loud and they arent's as deep as normal SPF pipes. Will follow up with results.....work has been insane so it may be a week or so on this item.