Simple bolt on questions. - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Accarroll23 · 01-09-2021, 07:14 AM

Hello guys I making this thread to get a little more advice on my car. I got some headers coming in the mail this week. I purchased my buddies 65lb injectors from a friend of mine. I was thinking of doing a lower pulley instead of an upper. I called a near by speed shop named National Speed. After talking the one of the salesman he recommended doing a 2.4 upper pulley and doing a solid isolator. After doing the math it makes perfect sense to go this route in my opinion. Its only a hundred bucks or so difference than doing a lower pulley, plus my isolator will be addressed.
After talking awhile and he did his research with all of the other similar builds that they've done he said I will not need the 65lb injectors. He said it will not help or hurt if i install them. My question is how many others out here has stayed with stock injectors with this similar setup. My mods will be, rotofab CAI, speed engineering longtubes with offroad pipes and 2.4 upper pulley and greenbelt. Im not doubting the guy but most of the threads I've read people say upgrade the injectors. Here's what he sent me in a message.

"Just double checked with product team and the previous data, we won't reach 85-90% duty cycle on stock LT4 injectors until about 740whp. So it won't hurt or help to install those DW's, do you think you could re sell them?"
Let me know what you guys think. He also said ill be in the 600whp range. Maybe more from there data from previous builds that are like mine. Thanks guys.

JB'sZL1 · 01-09-2021, 07:51 AM

Find a new speed shop. If he thinks you have an LT4 in your '13 Z, he needs to redo 2nd grade...on up.

Dave Karl · 01-09-2021, 09:49 AM

Quote:

Originally Posted by JB'sZL1

Find a new speed shop. If he thinks you have an LT4 in your '13 Z, he needs to redo 2nd grade...on up.

Agreed. The first thing I thought after reading the post.

Accarroll23 · 01-09-2021, 10:49 AM

The guy called me back and apologized. He thought I had an 18 not a 13. Injectors will be going in

RobZL1 · 01-09-2021, 01:15 PM

Regardless of the year model confusion, if they think you can run Direct Injection injectors in an LT4 up to anywhere near 85-90% duty cycle...run away.

Vegas Bound · 01-09-2021, 01:24 PM

Do yourself a favor and get your brick reenforced. You will be adding boost and it may collapse. I'm running 2.38/9.1 pulleys at 17 psi on e85 with 130 lb injectors at 65%. Don't waste your time on 65 lb injectors. You will be doing more mods in the future, plan for it now. Get at least 1050 or 1300 injectors and an aux pump.

RobZL1 · 01-09-2021, 09:23 PM

Quote:

Originally Posted by Smitty CC

True at that... 85-90% is probably considered the static point on any injectors for these cars.

In our cars, I'd stop at 85%, personally. I was just saying that in a LT4, it's a different ballgame entirely. Much less window. 4-5ms pulsewidths are the norm (can't really go above 5ms or so), and conventionally calculated duty cycles can't really go above about 40%. My point was just that I hope the shop knows what they are doing. Anyway, its a gen 4 motor we're talking about here, so most shops know what's up, I guess. The guy he was talking to probably wasn't the tuner anyway.

Accarroll23 · 01-09-2021, 10:41 PM

Quote:

Originally Posted by Vegas Bound

Do yourself a favor and get your brick reenforced. You will be adding boost and it may collapse. I'm running 2.38/9.1 pulleys at 17 psi on e85 with 130 lb injectors at 65%. Don't waste your time on 65 lb injectors. You will be doing more mods in the future, plan for it now. Get at least 1050 or 1300 injectors and an aux pump.

If I had the spare cash I would better different injectors. I got these from my buddy for a couple hundred bucks. Later down the road I'll upgrade. I wish my money wasn't tight but I left my fiance and pay support on 3 kids so im just doing what I can to wake this thing up a little. The shop I go to is very high end and have done some serious builds. The salesman that im working with felt stupid when he realized that he was thinking about a completely different year model. Im going to get the 2.4 upper, New belt and throw these injectors in it. Im installing my longtubes and injectors myself to save on labor costs.

Shodown · 01-10-2021, 09:10 AM

Quote:

Originally Posted by Accarroll23

If I had the spare cash I would better different injectors. I got these from my buddy for a couple hundred bucks. Later down the road I'll upgrade. I wish my money wasn't tight but I left my fiance and pay support on 3 kids so im just doing what I can to wake this thing up a little. The shop I go to is very high end and have done some serious builds. The salesman that im working with felt stupid when he realized that he was thinking about a completely different year model. Im going to get the 2.4 upper, New belt and throw these injectors in it. Im installing my longtubes and injectors myself to save on labor costs.

65 lb injectors are not even close to enough for a 2.4 upper pulley I wouldn’t think. That’s only 682.5 cc/min. You’re gonna need at least 100 lb (1050cc) on 93 or even more depending on how your car reacts with that small of an upper pulley on an LSA. As mentioned above by Vegas Bound don’t forget that your fuel pump will need help with a BAP or aux pump too and reinforce the brick.

Adding that much boost and “just throwing in” those injectors sounds disastrous. With 65 lb injectors you might get away with a 2.55 upper but even that would be pushing it if you’re trying stay around 85-90% injector duty cycle.

tartagliazl1 · 01-10-2021, 11:19 AM

I’m running 850cc injectors, bap, and meth with my 2.5 and 9.55” lower with a duty cycle around 70. So yeah you will need bigger injectors.

DRKS1D3 · 01-11-2021, 06:59 AM

Quote:

Originally Posted by Accarroll23

If I had the spare cash I would better different injectors. I got these from my buddy for a couple hundred bucks. Later down the road I'll upgrade. I wish my money wasn't tight but I left my fiance and pay support on 3 kids so im just doing what I can to wake this thing up a little. The shop I go to is very high end and have done some serious builds. The salesman that im working with felt stupid when he realized that he was thinking about a completely different year model. Im going to get the 2.4 upper, New belt and throw these injectors in it. Im installing my longtubes and injectors myself to save on labor costs.

You openly admit that you're not in the best financial situation, but you choose to modify your car anyways AND purchase USED parts? Priorities...

Hey man, best of luck with the build.

Accarroll23 · 01-18-2021, 08:23 PM

Quote:

Originally Posted by DRKS1D3

You openly admit that you're not in the best financial situation, but you choose to modify your car anyways AND purchase USED parts? Priorities...

Hey man, best of luck with the build.

I didn't say I was poor or broke. Im just going off of my budget at hand. As for used parts...I bought some injectors from my buddy that no longer needed them. The rest of my stuff is new. I wouldnt dare put money in this car is it set me backwards. I'm not stupid or that irresponsible. My priorities are well taken care of I'm just not rich like most of the guys on this forum. Ill post my numbers once the car is tuned next month. Thanks for the advice though.

JB'sZL1 · 01-19-2021, 06:11 AM

Maybe this could have been stated better. I took it as he was questioning used parts on mods, where hp gains are the objective. Although he wrote more.

I don't know most guys on this board, but I suspect most of them are not rich...rather some part of the middle class. No one called you stupid or irresponsible.

I would just like to see pre and post dyno, with some pics if you please.

silversleeper · 01-19-2021, 09:59 AM

I'm confused, what is the question?
Did you already buy those things? Are you set in stone on them?

No you don't need different injectors and no, that advice isn't the whole story on won't help or hurt to change them. Yes won't give you more hp to change injectors to any bigger ones. But it does require tuning and some tuners are better than others, so it costs and hurts performance unless needed and done right.

Long tube header's I'd skip in the LSA unless you are going after the higher hp and more expensive route.

If I did mods all over again I'd try just a 10% pulley with no tune or other mods and see if that was enough.
I went with more mods and e85, I enjoy the hellcat power right now, because hp is my biggest enjoyment, besides looks and comfort and handling.

01-09-2021, 07:14 AM	#1
Accarroll23 Drives: 2013 zl1 Join Date: Jan 2019 Location: Va Posts: 44 View My Garage	Simple bolt on questions. Hello guys I making this thread to get a little more advice on my car. I got some headers coming in the mail this week. I purchased my buddies 65lb injectors from a friend of mine. I was thinking of doing a lower pulley instead of an upper. I called a near by speed shop named National Speed. After talking the one of the salesman he recommended doing a 2.4 upper pulley and doing a solid isolator. After doing the math it makes perfect sense to go this route in my opinion. Its only a hundred bucks or so difference than doing a lower pulley, plus my isolator will be addressed. After talking awhile and he did his research with all of the other similar builds that they've done he said I will not need the 65lb injectors. He said it will not help or hurt if i install them. My question is how many others out here has stayed with stock injectors with this similar setup. My mods will be, rotofab CAI, speed engineering longtubes with offroad pipes and 2.4 upper pulley and greenbelt. Im not doubting the guy but most of the threads I've read people say upgrade the injectors. Here's what he sent me in a message. "Just double checked with product team and the previous data, we won't reach 85-90% duty cycle on stock LT4 injectors until about 740whp. So it won't hurt or help to install those DW's, do you think you could re sell them?" Let me know what you guys think. He also said ill be in the 600whp range. Maybe more from there data from previous builds that are like mine. Thanks guys.

01-09-2021, 01:15 PM	#5
RobZL1 fo'shizZL1 Drives: 2017 ZL1 Join Date: Aug 2017 Location: ATL Posts: 1,281	Regardless of the year model confusion, if they think you can run Direct Injection injectors in an LT4 up to anywhere near 85-90% duty cycle...run away. __________________ 2017 ZL1 M6 Black \| Maggie 2650 // 103TB // Big Gulp Past Rides- 2014 ZL1 M6 Red Hot \| Tons of mods 2004 CTS-V M6 Silver \| Many mods 1995 Corvette M6 Torch Red \| A few more mods 1992 Camaro M5 White \| A few mods

01-10-2021, 11:19 AM	#10
tartagliazl1 Drives: 2013 zl1 vert Join Date: Dec 2018 Location: Rochester, New york Posts: 949	I’m running 850cc injectors, bap, and meth with my 2.5 and 9.55” lower with a duty cycle around 70. So yeah you will need bigger injectors. __________________ 22% lower/ 2.5 upper/ 2” headers/ cat delete/ x-pipe/ 2 gallon x tank/ 100-3 pump/ fic 850/ dsx aux kit/ 103mm throttle body/ RPM 5” intake/ meth kit/ prometh lid injection/FI interchiller/ 160* stat/ ngk-7/ msd wires/ elite catch can/ tsp cam/ Che trunnions/ ported supercharger/ 1/2” lid spacer/ brick mod/BMR toe and trailing arms/ 751hp 757 tq SAE @17.3lb on a loaded dyno. Last edited by tartagliazl1; 01-11-2021 at 08:43 PM.

01-09-2021, 07:51 AM	#2
JB'sZL1 Drives: 2013 ZL1 and 2019 Ram Laramie Join Date: May 2017 Location: Milwaukee Posts: 1,259	Find a new speed shop. If he thinks you have an LT4 in your '13 Z, he needs to redo 2nd grade...on up.

01-09-2021, 10:49 AM	#4
Accarroll23 Drives: 2013 zl1 Join Date: Jan 2019 Location: Va Posts: 44 View My Garage	The guy called me back and apologized. He thought I had an 18 not a 13. Injectors will be going in

01-09-2021, 01:24 PM	#6
Vegas Bound Account Suspended Drives: 2013 Sparkly Red One Join Date: Dec 2018 Location: Hospitality State Posts: 2,558	Do yourself a favor and get your brick reenforced. You will be adding boost and it may collapse. I'm running 2.38/9.1 pulleys at 17 psi on e85 with 130 lb injectors at 65%. Don't waste your time on 65 lb injectors. You will be doing more mods in the future, plan for it now. Get at least 1050 or 1300 injectors and an aux pump.

01-19-2021, 06:11 AM	#13
JB'sZL1 Drives: 2013 ZL1 and 2019 Ram Laramie Join Date: May 2017 Location: Milwaukee Posts: 1,259	Maybe this could have been stated better. I took it as he was questioning used parts on mods, where hp gains are the objective. Although he wrote more. I don't know most guys on this board, but I suspect most of them are not rich...rather some part of the middle class. No one called you stupid or irresponsible. I would just like to see pre and post dyno, with some pics if you please.

01-19-2021, 09:59 AM	#14
silversleeper Big Crow Drives: '13 ZL1 Join Date: Mar 2017 Location: California Posts: 1,486	I'm confused, what is the question? Did you already buy those things? Are you set in stone on them? No you don't need different injectors and no, that advice isn't the whole story on won't help or hurt to change them. Yes won't give you more hp to change injectors to any bigger ones. But it does require tuning and some tuners are better than others, so it costs and hurts performance unless needed and done right. Long tube header's I'd skip in the LSA unless you are going after the higher hp and more expensive route. If I did mods all over again I'd try just a 10% pulley with no tune or other mods and see if that was enough. I went with more mods and e85, I enjoy the hellcat power right now, because hp is my biggest enjoyment, besides looks and comfort and handling.