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Hi everyone, so my 350z de is an automatic and is fbo with jwt c8 272 cams and is tuned, runs smooth and feels health other than lack of torque. On the dyno the car made 276whp and only 225tq, I’ve seen an automatic g35 de with same cams and similar bolt on’s make 290whp and 272tq. I really feel like something is off because my car made 10ft lbs more torque before the addition on cams, headers, and fuel system. The general lack of torque is very noticeable and the car ran a 13.78@100 before the cams and headers, and now the best time the car runs is a 14.2@102. Any insight or info on what may be causing my build to make such lackluster torque numbers, I feel the whp should be a little higher, but the biggest concern is the extremely low torque. I want to solve this because after all the money spent I don’t understand why I’m making 40-50 less torque than other similar 5at builds.
(yes I know it’s an auto, I a future cd009 swap lined out). (And yes I know I should’ve gone fi).
I can think of two things off the top of my head…and they may have no impact (and assuming you have a formal tune)
1. Did anyone tune your shift points AT for your engine mods?
2. Your intake is killing you…peak torque occurs when the engine is most efficient and by efficient I mean it can get the most air in and out of the cylinder, mixed with the right amount of fuel, combusting as much air:fuel possible
-what port & polish did you do to the manifold?
-what port & polish did you do to the plenum?
-were these done before or after your lost all your torque?
Martin (RS Enthalpy) tuned me. Uprev.
im not sure about shift points as when I drive it hard I use the silly “manual” mode. And the rev limiter is set to 7200rpm.
I have the VQ boys performance ported lower intake manifold. (I’ll link)
I have the VQ boys performance middle collector (lower plenum) (I’ll link)
my upper plenum is the black Kinetix V+ plenum.
BEFORE: I had admin 3.5” intake, nwp 75mm tb, motordyne 5/16 plenum spacer, test pipes, y-pipe and invidia n1 exhaust. And tune. Made 252whp 235wtq.
Now I have my engine rebuilt with the addition of the ported manifold and lower plenum, and V+ upper plenum, and headers, and bigger fuel system with e85, and the 272 cams. Made 276whp 225wtq… all that and the cams only gained me 20hp and lost me 10torque…
I agree with bealljk, your tuner needs to sharpen his pencil. Consider having a polite conversation about improving the performance. If he taps out talk to Jon at Z1 about an e-tune, you will not be disappointed.
I agree with bealljk, your tuner needs to sharpen his pencil. Consider having a polite conversation about improving the performance. If he taps out talk to Jon at Z1 about an e-tune, you will not be disappointed.
Well that’s the thing, we e-tuned the car and I wasn’t happy with it so I told him, so I rented a local dyno and we remote dyno tuned it to try to dial it in, we gained like another 4 or 5 hp but that’s it. And Martin at RS Enthalpy is considered by many as one of the top tuners for VQ’s and a veteran with these cars, and I’ve seen him tune some 300whp cammed n/a DE’s.
Perhaps you’re right, but at the same time I don’t want to spend all the money for a retune and have the same results if it turns out to be something other than the tune causing the low torque/power. Rs-Enthalpy is a very reputable tuner
I gutted a Rev-up intake manifold (against a few peoples recommendation) and it really pushed my torque further up the rev-range. I immediately went back to an OEM setup.
I would put an unmolested OEM manifold and OEM lower plenum back on the car and see how it does.
I dont know much about the VQ Boys (not saying they messed anything up) but I think this is the issue …
the problem with ‘full bolt ons’ is that you are essentially un-engieering the tens of thousands of hours Nissan put into research & design of the intake:
I am not an expert on air intake design but what you have violates a few principles of airflow intake design:
3.5” intake to a 3” throttle body (speeds up airflow at the 3” throttle body)
3” throttle body to a 2.75” OEM plenum neck (further speeds up airflow at 2.75” OEM neck, then slows down as it goes around the neck)
2.75” OEM plenum neck to a larger than stock airbox (slows down airflow in the larger than stock airbox)
larger than stock air box to a larger than stock lower plenum & manifold (slows down airflow through the ported & polished lower/manifold)
so now you have decreased the speed of the airflow as it travels though the intake and the decreased airflow speed means a less efficient filling of the cylinder, less filling means less air, which means less fuel, which means less power and less torque.
keep the 3.5” intake, 3” TB, and Kinetix upper plenum, put an OEM DE lower plenum and manifold back on the car. See how it feels and then go get a few dyno pulls in.
I’ve heard good things and bad things about Martin, I have had one direct experience with him on a customer’s car and I was not impressed.
I have had many interactions with Moncef, both on customer cars and my own cars too - I wouldnt ever go back to Martin and I would go talk to Moncef. Tell him your upgrades/mods, and have him re-tune you.
I gutted a Rev-up intake manifold (against a few peoples recommendation) and it really pushed my torque further up the rev-range. I immediately went back to an OEM setup.
I would put an unmolested OEM manifold and OEM lower plenum back on the car and see how it does.
Okay, I’m going to start looking/asking around to see if I can find an unmolested manifold and lower plenum.
Thank you for the insight. Now my question is, if I do swap my lower plenum and manifold for oem, will I need a retune to tell/feel if this solved the issue, because I’d hope to be able to feel/know for sure that this is the fix before I pay Admin for a new tune?
Ok, here's my input:
RS is known, yes this is true, Z1 is known but my E-tune experience with them was **** poor.
Admin tuned my car and I have ZERO complaints.
All that being said nobody has asked the very important question (unless I missed it) do you have widebands? If not that should be priority #1, yes you could use one on a dyno but if you did want to retune with Moncef he will require you to have them.
Next let's talk setup: I agree with Beall 100% at no point do you need a P&P manifold, it's big and polishing hurts more than it helps, porting to port match should be the most you want to do. You also have a very aggressive intake and a mild exhaust which isn't ideal, the DC headers are garbage and you don't even have cats so why didn't you go with PPEs? LTH are the best when it comes down to that but if you want short headers you have 3 options Nismo, Tomei and Z1, all others have terrible designs and will make you lose power in stock form, let alone tuned.
My car felt terrible when I had my E-tune from Z1 when I installed the widebands later I found out my AFRs were hitting 9s that's just terrible and at WOT I was between 10-11 that's not even remotely good for a NA car. I have a honed lower (basically an MREV2 copy) that I could sell but my entire manifold is a matched set and powdercoated so I'd rather sell it as a unit. If you can't find one shoot me an offer for the lower and we can talk.
Ok, here's my input:
RS is known, yes this is true, Z1 is known but my E-tune experience with them was **** poor.
Admin tuned my car and I have ZERO complaints.
All that being said nobody has asked the very important question (unless I missed it) do you have widebands? If not that should be priority #1, yes you could use one on a dyno but if you did want to retune with Moncef he will require you to have them.
Next let's talk setup: I agree with Beall 100% at no point do you need a P&P manifold, it's big and polishing hurts more than it helps, porting to port match should be the most you want to do. You also have a very aggressive intake and a mild exhaust which isn't ideal, the DC headers are garbage and you don't even have cats so why didn't you go with PPEs? LTH are the best when it comes down to that but if you want short headers you have 3 options Nismo, Tomei and Z1, all others have terrible designs and will make you lose power in stock form, let alone tuned.
So my biggest issue would likely be my P&P manifold and lower plenum? And likely changing these back to stock I could gain back some of my lost torque? Also, again if I swap these to stock would I be able to tell that this solved the problem by feeling an increase in low end torque Before paying for and getting a retune? Or would the only way to tell be after retuning?
Lastly, I thought my year had wideband 02’s from the factory?
My vote goes to stock plenum + Motordyne spacer as well.
That Y-pipe and exhaust choice might be a choke point... no? Looks like huge on the way in, tight on the way out.
I had similar mods minus the funky plenum business, and minus the cams, aaand minus the Transgo. My tuner (Radek, TO Canada) mentioned tuning the TCM with Uprev within the first 5 minutes, it's a can't-miss item when you're messing around with timing and AFR this much (IIRC).
He said he maxed out the injectors across a wider range than he thought, redline was set at 7,000 flat; dyno was a Dyno Dynamics. You didn't mention the dyno 'model' you rented, was it the exact same as your baseline dyno?
You mentioned it being slower at the track, was that before or after the big 295's went on those 370Z 'sport' wheels? (going by your other thread where you mention the manual C6 grand sport...)
I had a 2006 Grand Touring 5AT w/ Admin 3.5" intake, NWP 75 mm TB, Skunk2 5/8" spacer (bad; didn't run strut bar), Borla headers (bad), Stillen HFC and Borla CBE.
Stock cams, stock plenum, stock tires sizes. 281 WHP / 231 lbs-ft. The "baseline" in the grapĥ is actually "headers, intake and TB just installed, completely untuned" and not the original baseline.
In Shannonville ON the car ran 14.0 @ 99.5 tuned, compared with the (very) old baseline of 14.6 @ 97.8 unmodded/untuned. Both ETAs were achieved three times at the track on each day, slight changes in trap speeds.
You should be blowing the absolute **** out of the above numbers with the cash you've put in this car. How's the Corvette btw?
My vote goes to stock plenum + Motordyne spacer as well.
That Y-pipe and exhaust choice might be a choke point... no? Looks like huge on the way in, tight on the way out.
I had similar mods minus the funky plenum business, and minus the cams, aaand minus the Transgo. My tuner (Radek, TO Canada) mentioned tuning the TCM with Uprev within the first 5 minutes, it's a can't-miss item when you're messing around with timing and AFR this much (IIRC).
He said he maxed out the injectors across a wider range than he thought, redline was set at 7,000 flat; dyno was a Dyno Dynamics. You didn't mention the dyno 'model' you rented, was it the exact same as your baseline dyno?
You mentioned it being slower at the track, was that before or after the big 295's went on those 370Z 'sport' wheels? (going by your other thread where you mention the manual C6 grand sport...)
I had a 2006 Grand Touring 5AT w/ Admin 3.5" intake, NWP 75 mm TB, Skunk2 5/8" spacer (bad; didn't run strut bar), Borla headers (bad), Stillen HFC and Borla CBE.
Stock cams, stock plenum, stock tires sizes. 281 WHP / 231 lbs-ft. The "baseline" in the grapĥ is actually "headers, intake and TB just installed, completely untuned" and not the original baseline.
In Shannonville ON the car ran 14.0 @ 99.5 tuned, compared with the (very) old baseline of 14.6 @ 97.8 unmodded/untuned. Both ETAs were achieved three times at the track on each day, slight changes in trap speeds.
You should be blowing the absolute **** out of the above numbers with the cash you've put in this car. How's the Corvette btw?
Yes, all of my dyno runs have always been on a dyno jet. My old 13.78@99 was on 18” with 255 tires. And my newer time after cam, headers and intake plenum/manifold setup was on 19” with 295 and was a 14.2@102. Even with the heavy tires I really hoped for an improvement on 1/4 time, but again what killed me was the sever lack of torque, I think my 60ft was something like 2.5 because of the ridiculously weak low end power.
Love the corvette, it changed my life, I never thought I’d even consider getting rid of my Z I put so much work into, but after getting used to the vette, I think about selling my Z all the time, especially now after these disappointing numbers.
So you think if I change back to a completely stock intake manifold/upper and lower plenum, with the addition of my old 5/16 spacer, I should make more power and have better #’s/times?
Also, lastly, if I switch back to the stock manifold/plenums would I be able to tell if it solved my problem before I get my retune? I plan on a retune but I’d hope to at least know if the problem is resolved before I pay for the tune.
Ok, here's my input:
RS is known, yes this is true, Z1 is known but my E-tune experience with them was **** poor.
Admin tuned my car and I have ZERO complaints.
All that being said nobody has asked the very important question (unless I missed it) do you have widebands? If not that should be priority #1, yes you could use one on a dyno but if you did want to retune with Moncef he will require you to have them.
Next let's talk setup: I agree with Beall 100% at no point do you need a P&P manifold, it's big and polishing hurts more than it helps, porting to port match should be the most you want to do. You also have a very aggressive intake and a mild exhaust which isn't ideal, the DC headers are garbage and you don't even have cats so why didn't you go with PPEs? LTH are the best when it comes down to that but if you want short headers you have 3 options Nismo, Tomei and Z1, all others have terrible designs and will make you lose power in stock form, let alone tuned.
Dark - I can see the exhaust mods done would mess with top end / redline horsepower … but mid range torque shouldnt be negatively effected by an upgraded exhaust??
100% get widebands, plural, one on each bank.
Originally Posted by Freudenthaler
So my biggest issue would likely be my P&P manifold and lower plenum? And likely changing these back to stock I could gain back some of my lost torque? Also, again if I swap these to stock would I be able to tell that this solved the problem by feeling an increase in low end torque Before paying for and getting a retune? Or would the only way to tell be after retuning?
Lastly, I thought my year had wideband 02’s from the factory?
Were all just speculating … you could have issues with your VVT or something else mechanical. All we know is all we know. Do you have any check engine lights on? Any other issues with the car?
You would probably feel the difference between 225ft-lbs and 260ft-lbs.
You will have to pay for a re-tune but it wont be as much as your initial tune as you already have the software.
Yes, do what Conway says… were all telling you to put a OEM manifold and lower plenum back on and report back.
Were all just speculating … you could have issues with your VVT or something else mechanical. All we know is all we know. Do you have any check engine lights on? Any other issues with the car?
Yes, do what Conway says… were all telling you to put a OEM manifold and lower plenum back on and report back.
The car actually runs great and is smooth and feels perfectly normal, except for the obvious lack of low end power. No check engine lights, Ive used uprev software to monitor my AFR’s and ignition timing ect, and all looks good as well.
Okay, I’ll source out a oem manifold and lower plenum, hook up some widebands, and talk to Moncef at AdminTuning and see if he can tune me this time. It’ll probably be several weeks/months but once this is all done, I’ll report back and let y’all know the results.
Ps. Bealljk and other, thank you for responding and the possible insight, just hearing other options/ideas has really helped me to stress less about all this. Thanks All!!!
11-22-2021, 05:30 PM
Please HELP!!! Lack of Torque on cammed VQ35DE!
