No low end power

Discussion in 'Mustang Chit Chat' started by ShelbySteve, Jan 23, 2021.

  1. ShelbySteve

    ShelbySteve Member

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    I’ve owned my car about 6 months now and the more I drive it, the more I realize the power down low sucks. Full bolt on car and hot Rod cams. Don’t know if maybe I just need a new tune (mid and high rpm it pulls pretty hard) or if I could use a set of gears. I was thinking of going to 4.10’s, but with eventually going boost I figured 3.73’s would be better. Any ideas besides going with a power adder for now?
     
  2. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    What bolt ons do you have? Who did the tune? Does the engine buck at low rpm?
    A 4.6 with bolt ons and Hot Rod cams will feel soft below 3200rpm even with an optimized tune. Your best solution is higher ratio axle gears but the choice will depend on the type of power adder. I'd suggest you go for a TVS or twin screw supercharger where you can get that instant low rpm boost you're looking for.
     
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  3. GlassTop09

    GlassTop09 Member

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    My 2 cents.......
    Tune wise this is where IMHO remote tuning (think Lito here) can help you the most w\ CL closed throttle (<30% TA opening) low RPM TQ output (most DD range) w\ those Hot Rod cams since their GI cam timing specs shift the powerband upwards (lesser low RPM TQ\HP to gain more mid & high RPM TQ\HP vs OEM cams to achieve the idle chopping sound) due to using datalogs of you actually doing "normal" driving to properly set up the CL VCT cam timing tables to maintain cylinder pressure during compression stroke as high as can be kept (along w\ spark timing advance) w\o detonation (IOW's the VCT cam timing kept at 0* for full cam advance timing during CL low RPM operation to not allow the PCM to do any emissions optimization by retarding cam timing to perform EGR functions which will lower max cylinder pressure during compression stroke as well as lower % of fresh air\fuel cylinder fill volume during intake stroke thus lower overall engine low RPM TQ\HP output in exchange for lower NOx emissions & increased MPG thru the IMRC closed (low RPM) tune mapping based on AAP load% desired as set by the driver & read by the PCM).
    But even this will only get you just so far w\ these Hot Rod cams during low RPM operation.....after tune mapping is optimized the only other thing outside of boost that can help w\ low RPM power\acceleration optimization w\ these cams will be gearing (like you've already mentioned).

    This is much easier to show & explain by looking at the IVO, IVC, EVO, EVC mapped cam timing points of these Hot Rod cams put up against the same mapped cam timing points of the OEM cams (which I have done & have copies of) relative to crankshaft rotation (which all are based off common VCT cam timing of 0* for apples to apples comparison) so the CL closed throttle VCT cam timing table mapping in the tune is critical to maintaining\optimizing max low RPM TQ\HP output during normal driving....even w\ the OEM cams in these 3V's, especially if NA & can be better optimized IMHO thru remote tuning vs thru a dyno.

    Again this is my 2 cents.......

    Hope this helps.
     
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  4. ShelbySteve

    ShelbySteve Member

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    LT’s, full exhaust,cai intake, ud pulleys, and I’m sure I’m forgetting some other stuff.

    The tune was done by a local shop in VA prior to me shipping the car to Texas. I have an SCT handheld but it’s an old version. The car does buck at low speed. Catch myself pushing the clutch back in fairly often to keep from stalking without slipping the clutch a little. I will also be going tvs or twin screw when I supercharge it, but I’m in the process of doing supporting mods like bigger brakes and upgrading the trans first.
     
  5. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    I suggest you talk to @fdjizm (Frank) since he has almost identical mods that put down ~340rwhp. I believe he has 4.30 axle gears, and he's in an exclusive club of stock displacement N/A 3V owners who's picked up an 11-sec timeslip.
     
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  6. ShelbySteve

    ShelbySteve Member

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    I have the dyno sheet and mine put down 329. I was looking into going with 4.10’s, but after some research on here I figured 3.73’s would probably be better with boost being the goal. Didn’t know if these cams usually lagged in the low end or if there was some great supporting mod such as a throttle body or something that could help.
     
    Last edited: Jan 24, 2021
  7. Pentalab

    Pentalab forum member

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    I woulda thought with LT's, you would have bucket loads of low end TQ ? That was the one mod on my 2010 that was blatantly obvious. JBA LT's are a lot longer than kooks, etc. Other mods are the small roush M90, Twin 62mm TB, catted H, 94 tune. 386 rwhp / 370 rwtq.... on an automatic.
     
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  8. tjm73

    tjm73 of Omicron Persei 8 S197 Team Member

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    I have always wondered why the 4.6 (all versions) feel soft on the bottom end. They have a respectable stroke. And it seems the bore shouldn't cause it to be soft. At least not directly. Which leaves the port airflow and cam specs as the likely culprits. I've long wondered if a custom set of cams would correct this feeling. But in the end it only has 281 cubic inches to work with.
     
  9. eighty6gt

    eighty6gt forum member

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    Get some 3.73's now, they work great on my blower car. Maybe put a truetrac in there at the same time.

    put money in the bank to buy a DOB setup with an M122 GT500 blower, should only take about a year unless you put 1000 in gamestop shares tomorrow morning, in which case you'll have it by market close.
     
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  10. ShelbySteve

    ShelbySteve Member

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    Should’ve posted the dyno sheet. Didn’t even think to look through the receipts and stuff I got with the car. Car has Mac long tubes, Ford racing cai, catted mid pipe with Mac pro chamber, borla axle back, bbk ud pulleys, and hot Rod cams. Assuming it still has the stock TB and it still has the 3.55 gears. The tq down low is terrible down low and I know it could be the cam profile among other things.

    Don’t have much experience here so does anyone think I should get ahold of Lito for a new tune or go ahead and do a tb and gears...or all of the above?
    FF312C4C-B60A-4840-BA93-B28CFDFDBF27.jpeg
     
  11. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    The best 3V cams for torque from off idle to 4400rpm are the OEM ones. Mine pulls briskly from 1250rpm (40mph) in 5th gear no problem. The perception of a "soft" bottom end is due to the sharp rise in the torque curve from 3300-4400rpm (stock cams) where the WOT cam timing retard begins to kick in to add more sparkle at higher rpm.
    A stock 3V actually produces more low rev torque than a stock pushrod 5.0 which was fabled for its strong low rev torque, and the VCT also helps the 3V produce more low rev torque than its 4.6 2V and 4V brethren.
    Just about all performance cams cause a torque loss below 4500rpm to varying degrees. Long tube headers, a 62mm TB, and higher ratio axle gears can mitigate it but there's no getting away from the effects of a longer duration cam on a relatively small displacement V8.
     
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  12. Pentalab

    Pentalab forum member

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    That's why I left the oem cams in there. Then toss in the twin 62mm, blower, 94 octane, LT's, DSS-DS, watts link, and tru-trac = plenty of low end tq. 2nd gear on the automatic is 14% lower than 2nd gear in the manual. 3rd gear in the auto is 16.5% lower than 3rd gear in the manual. That's why I left the oem 3.31 rear gear alone. You would require a 3.73 in the manual to achieve the same overall ratio in 2nd gear. You would require a 3.90 rear gear to get the same overall ratio in the manual..in 3rd gear.

    Manually shifted into 3rd gear at a red light, idling at 600 rpm, ( and oem 1.5 krpm stall converter).... mash the gas, shriek of rubber, and u go up to aprx 145 kph..all in 3rd. It's effortless really. That was just a test to see how it would pull from a red light, in 3rd gear, at idle. In 2nd gear, it will throw u into the back seat...up to 100 kph.

    I looked long and hard at cams, for both a NA streetcar...and also a blower street car, and came to the conclusion for a street car, there was no, or limited benefit.
     
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  13. ShelbySteve

    ShelbySteve Member

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    The car sounds amazing at idle. I’m pretty sure the factory cams are still in the pile of stock parts so besides labor, shouldn’t be an issue swapping back to stock when I decide to go FI. Until then I’ll go ahead and get the tb, gears, trutrac, and other supporting mods and boost it is. Maybe I can run across a cheap DOB setup before then:D
     
  14. eighty6gt

    eighty6gt forum member

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    Just get the gt500 throttle body when you do the blower. It won't do anything now.

    The blower will eliminate any issues with low end torque. Completely.

    I have comp 127300 cams which make power all over, but would have also done hot rods. Heck, get some 4.10's in there. When you do the blower can go to 305/45's out back.
     
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  15. Rich

    Rich Member

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    I have a very midly modified N/A 3V (Steeda CAI, FR500S, 4.10's, Eaton Tru-Trac, Lito 93 Tune) and I'll say this. The stock auto w/3.31's and stock LSD felt like a snail. My goal was to make mine a fun daily driver for under $1000 and I succeded (came in arounf $960). It's not a rocket ship, but with the tune, Tru-Trac and gears it accelerates VERY quickly and I am happy with it. Lito does wonders with the 3V and magic with the 5R55S. My car only had 21k on the clock when I got it so I didn't want to crack open a fresh factory engine, I wanted to see what kind of fun could be had with the stock engine and a few drivetrain mods. I did consider LT's and Detroit Rockers, but LT's with those cams would have moved the TQ higher in the rpm band and I do most of my driving between 2200 and 3000, lots of acceleration, but I usually hover around 2700.

    Long story short, 4.10s do wonders for these cars N/A. You said FI was in your future so I would go down a notch to 3.73 because with FI your just gonna be running useless rpms and shredding tires. If the tires are a spinnin...you aint a winnin :)
     
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  16. Rich

    Rich Member

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    That's very interesting. I didn't know that. The old 5.0 is praised all over, but the 3V rarely gets tossed into the same category. I for one, love the 3V engine. I've always felt like it was a great step between the 2V and 4V. People loooove the 4V, but N/A they are a snail down low and don't make decent power until your rev'em out. The VCT really shines in the 3V for that low end torque and high end hp with no compromises.
     
  17. Juice

    Juice forum member

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    A stock coyote is not a snail down low.
    Now ppl who eliminate the VCT for " big cams/big power" give up a lot of low end.
     
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  18. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    I think Rich was referring to the 4.6 4V motor that came in the New Edge Cobra and Mach 1.
    In the 4.6 3V you certainly give up a fair chunk of lower rpm torque when you opt for a bigger cam (Shelby Steve's torque curves graphically illustrate just how much). That effect would become even greater if you opted for a cam that requires cam phaser limiters or lockouts (SPR cams), thus reducing or eliminating VCT functionality. Those cams work best with ported heads that'll allow you to take advantage of the increased airflow at higher valve lift. Since the heads would also come with upgraded valve springs, you could rev the engine as high as ~7250rpm if you add the Ford Performance intake manifold with its shorter, wider runners.
     
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  19. Rich

    Rich Member

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    I was referring to the DOHC 4.6 4V that came in the 96-01 Cobra and 03-04 Mach 1.
     
  20. RED09GT

    RED09GT Equal Opportunity Offender S197 Team Member

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    These cars are 400-700lbs heavier than a fox body so the extra torque over the pushrod 5.0 isn't as apparent, no big revelation there.

    I couldn't stand the 3.55's with the stock motor, putting in Hot rod cams and keeping the stock gearing is just asking for frustration.
    As for what to do gearing wise-are you planning on sticking with the TR3650, or will you upgrade?
    Do you drag race it or do you just want a cruiser?

    I use 4.10 gears and a 2.97 geared TR6060 in a built motor turbo car, the 3.55's couldn't get the car out of the hole and were awkward AF for 1/8th mile as I was shifting <100ft from the traps. The car was 4/10th's faster with 4.10's even though turbos aren't supposed to like lower gears according to the internet.
    On the street, the 3.55's spun just as much as the 4.10's-the 4.10's just made it easier to pedal it and regain control.
     
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