When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
goona need you help, numbers are low (update Aug 1)
so i messaged tony already to figure out what i did wrong or what is wrong, but also posting here the car was on the dyno and here is the following
new 427, 4.125 bore, 4" stroke, 11.8 compression (this was assembled by erl, and was bought from the previous owner who only ran it once)
mamo 265 with pac springs, YT rockers and johnson 2126 LSR lifters
cam is 247/261
stock ls7 intake
nick williams 90, truck maf, FTRA lid and SSRA
the exhaust is temporarily 1 7/8" pacesetters with 18 inch extensions, didn't wanna break her in with the new kooks 2" coated headers
my numbers are posted below, keep in mind this same car, same dyno, same everything from the flywheel to the rear tires made 459/410 with a 346 H/C/I. the car is an M6 with ford 9 inch.
ALSO ALL THESE PULLS ARE ON THE SAME EXACT TUNE
Last edited by Floorman279; 08-01-2019 at 07:54 PM.
Reason: .....
so heres my problem, the car makes more power when warm then when hot, as well as ups the power band. with this weak exhaust and intake id imagine peak should be somewhere 6200-6300, no way in hell should it be in the 5000s.
the yellow line was the last pull before it sat for about 5-7 minutes. the blue pull was first one after sitting, and the green one was the pull after the blue. so as you can see, the numbers got better when it was warm. we can rule out anything airflow related due to this, as well as my vacuum was around 94, except the blue pull which was about 92.5, and the tuner said the intake side doesn't "NEED" to be addressed until you are under 90.
so what can shift rpm band and make less power when hot? he said literally all my numbers are right where he likes them. i figured at a minimum this thing should be making 560/525. adding 80 more cubes only got me 60 hp when hot????
Is the IAT reading correctly? They tend to fail hotter at least for me..
what do i need to do to confirm this....i do havve a scanner that tells me this......it has been tossing random TPS circuit codes. even after the tuner released it....he did check that the throttle when pushed at pedal maxes out at the same as when pushing on the tb which was like 96
and also how would IAT reading too hot or too cold affect this (not being a smartass trying to learn)
Last edited by Floorman279; 05-08-2019 at 04:58 PM.
Reason: ....
Most are a resister/thermister that changes with temp, so you heat the motor up, check the temp and compare to the spec for your sender...
You can also just pull the sender and bench test it for the correct resistance with a ohm meter, If its a single wire IAT double check the ground quality..
If the sensor is off by 20% its basically telling the ECU to pull timing ..
If the TPS is reading wrong really odd things can happen, its another bench test item.. there are some good videos out there on it.. Common problem for both..
Never use a IAT or TPS if its been dropped on the floor without checking it.. They have a delicate ceramic/carbon internal that doesn't like it..
Tell us what tony said. Combination is everything. What sucks here is Tony’s MSD, injectors, the correct TB, X-pipe exhaust, and another tune will cost big money...and you’ve already spent big money. That stock intake/TB/MAF is prolly choking the thing. Maybe consider going SD to open up intake tract?
you lost me on how to test the IAT, there is now way of checking it or having anything to compare it to since i just have the scanner, and how does heating the motor up affect this temp? FYI im running a 5 pin maf so its in there
if for any reason the TPS or IAT were causing the motor to pull timing, wouldnt the tuner see this?
what is your opinion on the bumps at the high end? my valvetrain is pretty darn quiet and from i googled if its valve float it wont ever level out, if you look it all but levels out for a few seconds.......
how off would my pushrod length have to be in order to keep a valve open? with rocker bolt turn i set up, 14 ranged from .038 to .045 cold preload, so right around where i wanna be when hot for the recommended .025 to .035 hot for the johnsons. one i did measure came out to being right around.048 so a little high but should be fine, while another came in light right around .035.
Tell us what tony said. Combination is everything. What sucks here is Tony’s MSD, injectors, the correct TB, X-pipe exhaust, and another tune will cost big money...and you’ve already spent big money. That stock intake/TB/MAF is prolly choking the thing. Maybe consider going SD to open up intake tract?
how would lack of breathing change where i peak and how much i make depending on engine temp?
and also how would IAT reading too hot or too cold affect this (not being a smartass trying to learn)
Me personally, with my experience (or lack there of compared to others on here):
I don't see how IAT would play a role here. As far as I'm concerned, as long as that throttle is open completely and the AFR checks out at 12.x - you're making as much power as you're going to. It looks like your AFR is hitting 12.75ish. you're definitely leaving some power on the table. You can easily/safely eek out a leaner AFR like 12.9/13 to gain some ponies. Unless, for some reason that would be deemed unsafe with your combo?
regardless.... I'll say that you're a little down on power, on a dynojet. My 427 with cathedral prc 247's @ 9.9:1 SCR and a 235/244 put down around 490 at the tire.
id expect that your 265 heads, significantly higher compression, and larger cam, should have netted you at the very least, around 550 to the tire?
Then again, I'm not running a 9" rear. I'm currently on borrowed time on a stocker.
Edit:
You're running a 90mm? You've got some power to gain there. Like Chev70 said... Ditch the maf. Go SD. go 102
i still dont understand how an airflow restriction would be causeing it to make significantly more power at different operating temps......i believe that is the issue we need to solve first correct?
like i said, my 9 inch isn't that bad if it made 460 from a non max effort HCI ls1
This is a brand new build, is it not? This is the first time the engine has been dyno'd and broken in...
Eventually, it will settle in to the power that it'll make. Looks like the power went up on the second pull.
Did they make any more pulls aside from these 3, afterwards?
I think the fact it's a new engine that's not yet completely broken in, and perhaps a condition where the rings are still seating... You get where I'm going with this. There's.going to be some inconsistency.
Edit:
Yes the tuner will see if timing is being *significantly* pulled.
I wanted to add also, that it would be worth pulling the plugs just to see their health/condition after the initial tuning/Dyno runs.
o there were a lot of pulls. these were the last 3 thats all..........these are siginificamty because it shows the heat issue and it dynoing differently......so i assume that the 8-10 dyno pulls just broke it in 90%? so the rest can happen with regular driving?
i flirted around with the idea that maybe the coils are getting hot and not supplying the spark it needs? its a stupid thought but definitely a cheap start, but these coils are gm stockers from my last motor
You made peak torque right where you should -- 5200 rpm. So that pretty much indicates the cam is installed correctly. You made decent torque, so the combustion efficiency is decent. Your AFR is holding mid 12's, so you're not out of pump or injector. There is likely some minor gains to be made in timing and fueling, but not to make it suddenly rev better and peak at a higher RPM. This thing should be peaking near 6800 rpm. If it had, I would guess at 570 or so HP just from RPM.
I agree with Chevelle, I think you have an intake issue. And by intake I mean everything from air filter to manifold. If you were logging, look at your map readings vs ambient. I bet you were pulling a 7 KPA vacuum at WOT. The card style maf is not helpful when it is installed in a F car. May as well open the throttle 75% for the amount of area it blocks. But even so, You would still need more intake regardless of the MAF. Another thing to check would be to take a IR gun and read all eight primaries. make sure all eight are hot. But if you can check your MAP readings during WOT vs key on engine off, that will confirm or rule out the intake is the issue.
by map readings are you talking about those 94 and 92 numbers my tuner said? when i asked him if i have any intake and forward air inlet issues, he said not until you get below 90 do you need to worry about it.
but plenty of cars out there making over 550 hp with a stock intake, why is mine any different? how does an intake explain making more when warm vs hot? i can pickup an infrared thats no problem......yea my torque number is a little shy but not totally worried, so heres my stupid theory, again no expert, but if torque seems fine, but hp doesnt, where does hp come in and tq does not? the high end of the band, so my issue is up high somewhere, also evidenced by the roughness up top
Ok it is a good question and not an easy answer, but here goes: torque best correlates with g/cyl. HP best correlates with total airflow. Your peak airflow and peak rpm will be very close to the same rpm. The two are related by algebra. So the deal is this -- at 5200 rpm, you are getting good cylinder full but are very near the maximum amount of air you can flow. As rpm increases, airflow does not increase, so power peaks early and falls off. Indicating the intake tract is the issue.
If your map readings are low 90's you need to open your intake up. 7kpa is 1 psi. You are down at least 1-psi. Another way to look at it. Ambient is 101 kpa. If you are down to 92, you are 9% down on power. 9% of 520 is 45-50 hp. That puts you ideally near 570. That is the math.
Some will argue the blockage is before the throttle if map drops, in which case, ditch the inlet and maf, run open throttle, and see what it does. If it still pulls map down, its the manifold.
Running better warm or hot or whatever likely has more to do with fueling and timing, but without a log or anything I can only guess. You do get less fluid resistance as engine warms up as well, so that plays in.
If this helps my 428 made 464 lbs torque on the stock ls7 manifold vs your 520, so your heads are kicking my heads ***.
the tuner said nothing about knock detonation or pulling timing. id imagine if any of those were occurring he would have seen it right? im ok with the theory of engines make less when hot, however i would say 5-8hp, but not 15, unless im wrong here. also would heat be enough to change where it peaks?
clutch shouldn't be slipping and i feel we would see that more if it was. monster stage 1 race clutch rated at 900
05-08-2019, 04:37 PM
goona need you help, numbers are low (update Aug 1) 
