Lower RWHP/TQ than expected
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On The Tree
Joined: Sep 2008
Posts: 114
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From: Upstate South Carolina
Lower RWHP/TQ than expected I have a TMS 370CI with stage 3 PP 243 heads, and a cam 236/248 615/615 110 LSA, LS6 intake and SLP Lid. I put it on the dyno and it didnt seem to be running out of fuel. More fuel would probably help but I only got 404 RWHP. To me that seems low. Any advice or opinions?? Im also rolling through a Strange S60. No dyno tune just a street tune. But it still seems low.
Just for reference I have a TMS 370CI with a LS6 intake, cam similar to yours, but with PRC stage 2.5/5.3 heads and made 420 rwhp on a Mustang dyno. I was told this dyno runs about 30-40 hp lower than most Dynojet dynos. I have a upgraded fuel system as well though
Having a street tune doesn't automatically mean it's a junk tune.
A tune optimized for the street does not necessarily translate to good dyno numbers and vice versa. That's why you should compare apples to apples, like a dyno tune on the dyno or a street/strip tune on the street or track.
Plus, without some sort of #s to back up the tune, there's no way to know that you're not leaving power with just street tuning. He either maxed out his timing without knock or just threw a random number on there. Who knows what sort of timing and fueling an engine likes best without a dyno or at least a track result.
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My car was street tuned only. Tuned to run 12.6-12.8 afr on my wideband and 27.5* timing. On the dyno the wideband showed a beautiful 12.7afr line and I had no knock retard where I am but trying to add more timing started to pick some up. What else could be done in a dyno tune to get more power?
OP, you are giving us NOTHING to work with.
What transmission in the car? What clutch/converter?
What headers and exhaust? If stock manifolds...mystery ******* solved.
What injectors? What was your air/fuel? (otherwise how do you know it wasn't running out of fuel?)
What does the curve look like? Is it rough up top? (potential valve float or other problems)
What wheels/tires on the car?
What gear was it dynoed in?
Can't solve a puzzle if we only have the 4 corner pieces.
OP, you are giving us NOTHING to work with.
What transmission in the car? What clutch/converter?
What headers and exhaust? If stock manifolds...mystery ******* solved.
What injectors? What was your air/fuel? (otherwise how do you know it wasn't running out of fuel?)
What does the curve look like? Is it rough up top? (potential valve float or other problems)
What wheels/tires on the car?
What gear was it dynoed in?
Can't solve a puzzle if we only have the 4 corner pieces.
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I have a TMS 370CI with stage 3 PP 243 heads, and a cam 236/248 615/615 110 LSA, LS6 intake and SLP Lid. I put it on the dyno and it didnt seem to be running out of fuel. More fuel would probably help but I only got 404 RWHP. To me that seems low. Any advice or opinions?? Im also rolling through a Strange S60. No dyno tune just a street tune. But it still seems low.
A street tune does not optimize a combination for power. Usually, the street tune only gets drivability and street manners squared away, while making it safe for runs in WOT. Since different combinations like different timing curves and different fuel curves, maximum power cannot be realized accurately without the dyno.
Any good street tune is going to be 99% optimized. You might pick up 10 rwhp on a dyno finding optimal timing and fueling. But as long as you're ~12.5 AFR on the street and you have a reasonable amount of timing, you are pretty much there. The dyno can allow you to unlock that last 1%.
Really, in an N/A car, adjusting AFR really doesn't do that much. Just set it to 12.5-12.8 and forget about it. It's going to vary gear to gear anyway (leaner in the lower gears, richer in the higher gears) which is why I just set it to 12.5 and forget it.
Timing is where you will gain power, but even if he had just the stock timing tables, he won't see more than 20 rwhp by adding timing, which would still leave him with very low numbers assuming this is a dynojet.
Geoff over at eps tuned my car on the street. Then straped it down to the dyno. I tell ya the man had my car within 3 HP of being done on the first pull. By the last pull That's all that was increased so id say a street tune can be pretty damn close!
If 10 of the same cars new off the showroom floor were taken to 10 different dynos you'd get 10 different numbers guaranteed.
Dyno numbers are pretty pointless without a before and after comparison. It's a tool for tuning your car. Not to give accurate HP estimations IMHO. Weigh your car in "race trim" and take it to the 1/4 mile track for a more accurate representation of wheel HP. Also ambient temps, elevation, air density etc all have huge effects.
Dyno numbers are pretty pointless without a before and after comparison. It's a tool for tuning your car. Not to give accurate HP estimations IMHO. Weigh your car in "race trim" and take it to the 1/4 mile track for a more accurate representation of wheel HP. Also ambient temps, elevation, air density etc all have huge effects.
If 10 of the same cars new off the showroom floor were taken to 10 different dynos you'd get 10 different numbers guaranteed.
Dyno numbers are pretty pointless without a before and after comparison. It's a tool for tuning your car. Not to give accurate HP estimations IMHO. Weigh your car in "race trim" and take it to the 1/4 mile track for a more accurate representation of wheel HP. Also ambient temps, elevation, air density etc all have huge effects.
Dyno numbers are pretty pointless without a before and after comparison. It's a tool for tuning your car. Not to give accurate HP estimations IMHO. Weigh your car in "race trim" and take it to the 1/4 mile track for a more accurate representation of wheel HP. Also ambient temps, elevation, air density etc all have huge effects.
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Right, we can't do anything here but speculate. We simply need more info if we are to pinpoint the issue, if there is one.
TECH Regular
Joined: Sep 2007
Posts: 443
Likes: 3
From: Kansas City, MO
If someone isn't doing the ve tables, timing, wideband, etc then they aren't doing a very good tune. I tune on the street and the last vehicle that we took to the dyno afterward didn't gain any power. Had it nailed on the street. There are also dyno tuners who don't do a thorough job either. Anyone can do a wot tune to get the best numbers at the dyno, but the airflow through a vehicle is different when the vehicle is actually moving. So the afr may differ from the dyno to the real world. I guess my point is that as long as the street tune is thorough, the power on the dyno shouldn't really change much.
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Let's strive to do better then this. 
Just a dyno number don't worry about it. Ny my car dynoed 384rwhp and 373rwtq with a 243 headed 370ci and ls6 intake with a 231/238 cam but it ran 11.73 at 116 the first outing
