Ford V8 Discussion Discussion relating to getting the most out of your Ford-based V8 Miata's engine

Stuck at 290 rwhp

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Old 11-14-2012, 10:55 AM
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Unhappy Stuck at 290 rwhp

As the title says, I'm 'stuck' at 290 and want to eclipse the 300 hp mark and would like to know where my hangup is because with my current setup I thought that I'd easily be over 3. I currently have:

302 bored to 306
24 lb injectors
BBK 70mm TB
Trick Flow track heat upper and lower intake
Trick Flow 170 aluminum heads
Trick Flow 1.6 RR
Comp cam with 555 and 565 lift with duration at 224 and 232
Hedman shorty headers

I am just wondering if I am limited with the headers. I do have a chip in it and had it tuned on a dyno but just can't seem to break that 300 HP mark.
Any thoughts, tips and or suggestions would be helpful. Thanks!
Old 11-14-2012, 12:53 PM
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What do you have from the headers back? Exhaust pipe size? Mufflers? Plugged cats? Heavily dimpled pipes due to chassis interference?

Also, since you're dealing with wheel hp, what trans and other drive train? Just curious here. For instance, I know that Ford 9" diffs consume more hp than most others because of their hypoid angle. Still they're popular for racing apps because of their great inherent strength. The thinking is, "I need a bullet proof diff. I can always find more hp to make up the difference." The diffs commonly used in V8Ms are not familiar to me, so I'm just asking if any one uses a higher than usual hypoid angle, and thus eats more power. Anyone?

HTH,

Lynn B.
Old 11-14-2012, 02:03 PM
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2.5 pipes, Dynomax exhaust, no cats and pipes in good shape. I've got a non-wc T5, 7.5 diff with a posi.
Old 11-14-2012, 09:42 PM
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At the flywheel you are well over the 300 hp mark. The drive trane eats about 35-40 hp.
At least you can feel good about that. Cars hp rating from all manufacturers is flywheel hp.
That being said your power to weight ratio (manufacturers & car mags.calculate from the flywheel) is in the 8# per hp range. A new 5.0 Mustang is 9:1. Enjoy, have fun, dyno numbers are just bragging rites. Get what you got to the ground and you can beat most cars on the road, both straight line and around corners!
Jack
Old 11-15-2012, 06:56 AM
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Is your air filter drawing cold air, or is it sucking hot air from under the hood?
Old 11-15-2012, 07:21 AM
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Unfortunately it is sucking in the hot air.....the dyno number is with the hood open and a fan blowing on it. I am trying to fab some type of duct work to funnel some cool air to the intake. The intake filter sits right above the headers.
Old 01-08-2021, 04:43 PM
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Hi, to get over 300hp at the wheels you need more airflow..

So you have some options...

1) Larger Cam around 232@ 50 or larger and 0.6 in lift will get you there if you only need an additional 10-20 rwhp
2) upgrade to TFS 190 11R heads (airflow jumps from about 260 cfm to 304 cfm) and TFS R intake manifold (airflow jump from 260 cfm to 290 cfm) to get a bigger kick of about 30 rwhp
3) Upgrade to 75mm TB if doing option 1and 2.
4) Do all of the above for the best result around 30-45 rwhp more...

note:...shorty exhaust may be an unavoidable limitation...but you will crack 320rwhp at 6500rpm with all the above

cheers,


Last edited by engineer; 01-08-2021 at 05:04 PM.
Old 01-09-2021, 09:29 AM
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Originally Posted by engineer
Hi, to get over 300hp at the wheels you need more airflow..

So you have some options...

1) Larger Cam around 232@ 50 or larger and 0.6 in lift will get you there if you only need an additional 10-20 rwhp
2) upgrade to TFS 190 11R heads (airflow jumps from about 260 cfm to 304 cfm) and TFS R intake manifold (airflow jump from 260 cfm to 290 cfm) to get a bigger kick of about 30 rwhp
3) Upgrade to 75mm TB if doing option 1and 2.
4) Do all of the above for the best result around 30-45 rwhp more...

note:...shorty exhaust may be an unavoidable limitation...but you will crack 320rwhp at 6500rpm with all the above

cheers,
Not sure if you noticed, but the last post on this thread was dated 11-15-2012
Old 01-10-2021, 02:26 AM
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Originally Posted by mrmustang
Not sure if you noticed, but the last post on this thread was dated 11-15-2012
Yeah I did..but I was just bored..hahah

I just thought it may be useful; for someone trawling the history...its a common sort of question
Old 01-11-2021, 10:51 AM
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Within the historical context of the thread being 9 years old........
The question itself exemplifies the reasoning for going with an LS based engine over a Ford engine.

It is much easier and cheaper to go LS as the desired horsepower level goes up.
300 HP at the rear wheel is close to the lowest level you get with an LS swap with the cheap and easy camshaft upgrade path to 400 HP, presuming that your LS engine does not already put out 400+ HP right from the start.

I will admit that the Ford engine sound better with a decent exhaust.
Old 01-12-2021, 06:57 PM
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Originally Posted by BGordon
Within the historical context of the thread being 9 years old........
The question itself exemplifies the reasoning for going with an LS based engine over a Ford engine.

It is much easier and cheaper to go LS as the desired horsepower level goes up.
300 HP at the rear wheel is close to the lowest level you get with an LS swap with the cheap and easy camshaft upgrade path to 400 HP, presuming that your LS engine does not already put out 400+ HP right from the start.

I will admit that the Ford engine sound better with a decent exhaust.
100% agree....LS motors are much better as they are a much newer design, aluminum block, more torque, more power, more scope to go harder...but I agree that the old ford engine sounds amazing...even if its not going anywhere in a hurry
Old 09-11-2021, 02:15 PM
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Looks like your problem is your injectors. Way too small. If you want more horses you need to go with either 32lb or why waste time, just go with 40lb injectors. 70mm will work, I have 165 heads, 32lb injectors, 65mm throttle body, and dyno tuned at 300 rwhp and 300ft/lbs torque. That was on a hot day with 87 octane fuel. On a cool day with 91 or 92 octane, who knows? I think maybe 325 or more rwhp. You will need a tune to make everything play together right.
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