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Discussion Starter · #1 ·
Please lend me so advise...............

Heres the scoop.....My winter project was MTI stage2 heads, elec. water pump, Spec. 3, Accels 32's and 4:10's.

Prior to, I was running a MTI X-1, LG's w/o cats, Pulleys, Ported T.B. and Borlas. With this set up I dynoed 425 rwhp/ 399 rwt. Good numbers for a cam only car. David at MTI made a point to tell me it was a above average cam only car. As all you know by adding the heads and elec. pump I was hoping to get 30-35 rwhp. Take away 10 +/- for the 4:10's and I'm around 450 or so.

So I get the thing togather last week, wait for the rain to clear, put some miles down to break in the clutch and cruise to 21CMC.

Somewhere between 2 weeks ago and now I lost 10 rwhp!!! That was AFTER ALL the new mods! :cen: Thats right, I put on the heads, water pump and all expecting to be looking at 450 +/- and I end up loosing 10 from the cam only dyno.

What the hell do you think is up?? Do you think I might have some funky heads?? Maybe some made for lower compression?? This is about all I could think would be making me have such losses. Maybe the chambers were cut big and my compression dropped :screwy: :-? :-?

Any help would be appriciated.

Thanks in advance guys, J
 

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could you be out of fuel? 450 at the wheels with electric waterpump should work out to about 500 at the crank, I'd think. I know my 502 ramjet has 38 lb injectors on it from GM. and its 510/560, might need some programming as well due to the heads.
 

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first question:

Did you use the same dyno for the cam only numbers? if not then go back and try it out. some dyno's are more conservative than others. think about it if each dyno varies +-10RWHP(possible) from the avearage and you dyno'd ur cam only set up at one of the higher reading dynos and dynod ur h/c setup at one of the lower reading dynos you could be looking at 20RWHP difference. Just a thought!
 

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Discussion Starter · #4 ·
undertaker said:
could you be out of fuel? 450 at the wheels with electric waterpump should work out to about 500 at the crank, I'd think. I know my 502 ramjet has 38 lb injectors on it from GM. and its 510/560, might need some programming as well due to the heads.
I had it tuned today as well and 415 is what we got AFTER the tune. I put 32 lb injectors and Andy has the AFR's perfect. I am puzzled.
 

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Discussion Starter · #5 ·
2002Z06Yellow said:
first question:

Did you use the same dyno for the cam only numbers? if not then go back and try it out. some dyno's are more conservative than others. think about it if each dyno varies +-10RWHP(possible) from the avearage and you dyno'd ur cam only set up at one of the higher reading dynos and dynod ur h/c setup at one of the lower reading dynos you could be looking at 20RWHP difference. Just a thought!
No..different dynos. However, when I originally had an edit done years back and after cam only the two dynos were 2 rwhp apart. I didn't dyno prior to my winter mods so I don't know if the 2 were close cam only.

BTW I'm sending you another pm on the tnt.
 

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Different dyno's could produce different numbers. Were both dyno runs done on a dynojet? I agree that you shouldn't have lost HP. Have you used any oil?
 

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Discussion Starter · #7 ·
case2307 said:
Different dyno's could produce different numbers. Were both dyno runs done on a dynojet? I agree that you shouldn't have lost HP. Have you used any oil?
You know thats a good question. Wait.....yes they both are dynojets.

No, I havent used any oil at all. Would you guys think that the numbers from cam only would have been this far off?
 

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Hmmm...I have no idea then...you should have picked up at least 30 HP at the wheels with heads. :-? Did you have the car retuned after you installed the heads?


xxxeditxxx I see that you did...that's really odd.
 

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Discussion Starter · #9 ·
case2307 said:
Hmmm...I have no idea then...you should have picked up at least 30 HP at the wheels with heads. :-? Did you have the car retuned after you installed the heads?


xxxeditxxx I see that you did...that's really odd.
I am stumped too. Would you think that somehow my CR got messed up. Maybe I got a bad set of heads or a set made for some SC car.
 

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Did you get a flow sheet when you bought your heads?
 

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Discussion Starter · #11 ·
case2307 said:
Did you get a flow sheet when you bought your heads?
Yep........301 intake 212 exhaust @ .600
 

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J.N.F. said:
No..different dynos. However, when I originally had an edit done years back and after cam only the two dynos were 2 rwhp apart. I didn't dyno prior to my winter mods so I don't know if the 2 were close cam only.

BTW I'm sending you another pm on the tnt.

If its not the same exact dyno then its not a valid comparison.

BTW i didnt get the pm.
 

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Have you done the numbers to make sure that you have enough intake and fuel to produce 500hp? What about exhaust? Where is the rev limiter set at? It sounds like you have enough motor, but something ain't right.
 

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Discussion Starter · #14 · (Edited)
02ElectronZ said:
Have you done the numbers to make sure that you have enough intake and fuel to produce 500hp? What about exhaust? Where is the rev limiter set at? It sounds like you have enough motor, but something ain't right.
Yea........I am getting enough fuel. I put 32's on with the head swap. The rev limiter is at 6800.

Something is for sure is off. The guys at 21CMC are thinking the heads are not cut right. Possibly cut to give me 9 to 9.5/1 CR. Everything else checks out. We got up to 29 degrees with no detonation.
 

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Discussion Starter · #15 ·
Talked to MTI today and they asked for the car. They didnt say however what could be happening. I asked if it was possible to have over cut the heads during polishing and they thought it was unlikely. Did say that that its possible that some pf the ports got thin during porting and cracked under pressure. I havent seen any smoke or anything though. This whole deal has made me ill.

Thanks to MTI for volunteering to help so quickly. No more ideas out there???

Thanks, J
 

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I know it's frustrating and it actually does give you a sick feeling. But look at it this way. All logic tells you that you gained HP, even though you arent seeing it in numbers. So with that in mind, have patience, and know that it's not the mod. Somthing is wrong and will be fixed. Give the MTI guys or 21C guys a chance to tell you what it is. Good Luck!
 

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Discussion Starter · #17 ·
Thanks for the support..........Kinda funny how we all become so attached to our cars that we ache when they are down.

WOW.........that sounded kinda sentimental. I need to show this to my girlfriend!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
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