Help with disappointing dyno results
07-02-2018, 02:40 PM
#1
Instructor
Thread Starter
Help with disappointing dyno results
I recently had the car tuned on a dyno prior to a blower but the dyno results were seriously disappointing. I can feel an improvement over stock but not ads much as I thought.
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
07-02-2018, 03:03 PM
#2
I recently had the car tuned on a dyno prior to a blower but the dyno results were seriously disappointing. I can feel an improvement over stock but not ads much as I thought.
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
You have a blower on top of all the other mods? The mods alone I would figure 300 whp. What does fuel pressure do when you are doing a dyno run? What size injectors do you have?
This could be a tuning issue. Hard to tell.
07-02-2018, 03:11 PM
#3
Instructor
Thread Starter
No blower yet I wanted a before and after comparison. After fixing a vacuum leak on the intake the car needed to be retuned. Not sure what the fuel pressure was on the dyno but when the key is on (engine off) it’s at 40psi. At idle fuel pressure goes to 50psi
07-02-2018, 03:18 PM
#4
Gotcha. I am hesitant to say so, but I think this may be a tuning issue. Unless there is something drastically wrong (misfiring, valves not lashed/hanging open), I would expect a little more out of your setup.
07-02-2018, 03:19 PM
#5
Safety Car
What fuel injectors do you have? I have similar mods, minus the heads, and am running Bosch 3 24lb hr injectors. I also began tuning and it makes a big difference. Just changing the injector size and full throttle power enrichment was noticeable.
07-02-2018, 04:40 PM
#8
Safety Car
I recently had the car tuned on a dyno prior to a blower but the dyno results were seriously disappointing. I can feel an improvement over stock but not ads much as I thought.
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
It only made 250 rear wheel hp!!!
The car starts hard (I expected this since we removed the 9th injector) and surges on cold start up but the surge goes away as it warms up.
My mods are:
Engine:
80000 km’s (aprox 50k miles)
Stock bottom end
AFR 180 eliminator heads
Comp 268 xfi hr13 ( duration @50 218/224)
High flow L98 base, ported SLP runners, ported plenum
Adjustable fuel pressure regulator
Exhaust:
Long tube headers
True dual exhaust
Magnaflow mufflers
Transmission:
700r4
2400 stall torque converter
Shift kit
Considering everything I’ve heard on the forums I think something is wrong. If anyone has any words of advice please chime in
07-02-2018, 05:52 PM
#11
It’s easy....you are running a choking intake system....that base and runner do nothing over the stock long runner set up...makes torque, not horsepower....mini ram will provide about 40 rwhp over that....with the same time tune....after a tune ....even better....ask me how I know!!
surprised it’s not making more rwtrq though.
surprised it’s not making more rwtrq though.
Last edited by 856SPEED; 07-02-2018 at 05:55 PM.
07-02-2018, 06:21 PM
#12
Team Owner
Member Since: Oct 2004
Location: altered state
Posts: 81,242
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St. Jude Donor '05
elaborate on high flow base?
You need the right sized injectros and a good tune thats holding you back big time.
Look up Wongs Performance in Vancouver
You need the right sized injectros and a good tune thats holding you back big time.
Look up Wongs Performance in Vancouver
07-02-2018, 06:22 PM
#13
Le Mans Master
..... 250 rear wheel hp is actually a nice improvement over stock rated 240 flywheel hp … small-ish heads , small cam , TPI and Long tubes got you 50-60hp over stock ! … nothing wrong with that ! …..
07-02-2018, 06:24 PM
#14
Team Owner
Member Since: Sep 2001
Location: Athens AL
Posts: 59,642
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C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Is the chip custom tuned for this camshaft
07-02-2018, 06:28 PM
#15
Instructor
Thread Starter
It’s easy....you are running a choking intake system....that base and runner do nothing over the stock long runner set up...makes torque, not horsepower....mini ram will provide about 40 rwhp over that....with the same time tune....after a tune ....even better....ask me how I know!!
surprised it’s not making more rwtrq though.
surprised it’s not making more rwtrq though.
yup. That was the cam that was in it during the dyno tune
07-02-2018, 06:38 PM
#17
Instructor
Thread Starter
07-02-2018, 06:48 PM
#18
Instructor
Thread Starter
What do you reccomend as far as injectors? I have to swap them out anyway when I move to a blower
07-02-2018, 07:15 PM
#19
Race Director
What timing are you running?
07-02-2018, 09:52 PM
#20
Instructor
Thread Starter