Low boost 5.3 octane and meth
Low boost 5.3 octane and meth Basically stock 5.3, lightly decked 806 heads to clean up, stock pistons/gaps/ebay MLS stock replacement head gaskets. Summit 8719 cam 209/217 .550 cam and dorman LS6 intake. VS racing billet 70/70 turbo 2.5" right to the TB. I'm going to add a 50mm ebay tial BOV and I am going to run a snow performance 300psi pump with either a 250ml/500ml/750ml nozzle. Summit 60mm WG trying to limit boost between 4-6psi and trying to think of the tune or if I need intercooling (wiper fluid). Engine ran fine (clean plugs) on 87 NA before the turbo. I would love to obviously run 87 with a light water/meth spray but thinking maybe I need 91 or so to be safe? Are you guys even retarding timing at that low of boost? The price split between 87 and 93 is alittle more than $1/gal so its not a huge deal but if I'm spraying meth for intercooling do I need the 93? I guess what do you guys think for octane at the pump and how much meth should I spray? I was going to use an output on the holley to control a relay to activate the pump so it could come on at say 2-4psi.
- How much wiper fluid would you spray?
- What min octane for gas?
- Meth activation PSI?
- Timing pull at 4-6psi? I was thinking maybe 4* max to be safe and maybe 2* attached to the IAT in case it heat soaks which it likely will. NA with a filter in the engine bay I was seeing 140+ IATs in traffic. I did a ram air and temps dropped significantly but I can't do that with the turbo obiously.
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
Ideal gas law says that 80 degree air becomes 141 degrees when compressing 6 PSI, and 100 degree air becomes 162 degrees when compressing to 6 PSI.
I don't know what your climate is, but you should expect a ~60 degree increase at 6 PSI.
You could get away with 93 octane without either an intercooler or meth at that boost level.
With 87, I would recommend water/meth, just typical -20F blue washer fluid is great stuff and is cheap, and I'd have it come on immediately in boost.
One degree per PSI is the rule of thumb for boost, but that obviously varies based on what the timing is set to initially, and octane used.
A more aggressive tune or an inferior octane should consider pulling more.
I don't know what your climate is, but you should expect a ~60 degree increase at 6 PSI.
You could get away with 93 octane without either an intercooler or meth at that boost level.
With 87, I would recommend water/meth, just typical -20F blue washer fluid is great stuff and is cheap, and I'd have it come on immediately in boost.
One degree per PSI is the rule of thumb for boost, but that obviously varies based on what the timing is set to initially, and octane used.
A more aggressive tune or an inferior octane should consider pulling more.
Ideal gas law says that 80 degree air becomes 141 degrees when compressing 6 PSI, and 100 degree air becomes 162 degrees when compressing to 6 PSI.
I don't know what your climate is, but you should expect a ~60 degree increase at 6 PSI.
You could get away with 93 octane without either an intercooler or meth at that boost level.
With 87, I would recommend water/meth, just typical -20F blue washer fluid is great stuff and is cheap, and I'd have it come on immediately in boost.
One degree per PSI is the rule of thumb for boost, but that obviously varies based on what the timing is set to initially, and octane used.
A more aggressive tune or an inferior octane should consider pulling more.
I don't know what your climate is, but you should expect a ~60 degree increase at 6 PSI.
You could get away with 93 octane without either an intercooler or meth at that boost level.
With 87, I would recommend water/meth, just typical -20F blue washer fluid is great stuff and is cheap, and I'd have it come on immediately in boost.
One degree per PSI is the rule of thumb for boost, but that obviously varies based on what the timing is set to initially, and octane used.
A more aggressive tune or an inferior octane should consider pulling more.
Any experience with the motion raceworks Href Hi temp IAT sensors? I got a new fast EFI IAT but ran across these Href sensors... $80 for a sensor ouch... wonder if its worth it? Reason I like it is for the accuracy and speed but also that I can get it in small 1/8 NPT size.
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
High cruising temps are almost always heat soak. Its very common to see IATs drop down when going wide open throttle, even without increasing speed by a lot. The mass of the incoming air is able to cool the sensor down to read the temp more accurately, where at cruising speed the heat being applied can't be offset by the relatively low amount of air mass moving past it.
No experience with the Motion sensors. Stuff like this is always very situational to me. The difference between reading 194 degree intake temps and a "more accurate" 182 degree temp is marginal in most setups.
No experience with the Motion sensors. Stuff like this is always very situational to me. The difference between reading 194 degree intake temps and a "more accurate" 182 degree temp is marginal in most setups.
The temp range I will be using the car will be 50*F - 100*F ambient. Couple that with the turbo placement and possible filter right on the turbo it would be sucking in hot underhood air. when the engine was NA I would see 140's IAT temp while cruising. The filter on the turbo is basically in the same place as that setup so 140*F base plus turbo heat plus compression. I'm going to spray wiper fluid no matter what just for the safety. I currently was getting it setup with the 2 GPH Snow nozzle at 100psi but I'm running a 300psi snow pump. If we figure a 60* increase on say 140* that puts me close to 200* then figure the water/meth and probably 91-93 octane. This is a daily driver type car so if I'm not running 87 then going to 89/91 the savings isn't really there and I might as well just go to the 93 if it cost me $5 a week difference to drive the car.
Any experience with the motion raceworks Href Hi temp IAT sensors? I got a new fast EFI IAT but ran across these Href sensors... $80 for a sensor ouch... wonder if its worth it? Reason I like it is for the accuracy and speed but also that I can get it in small 1/8 NPT size.
Any experience with the motion raceworks Href Hi temp IAT sensors? I got a new fast EFI IAT but ran across these Href sensors... $80 for a sensor ouch... wonder if its worth it? Reason I like it is for the accuracy and speed but also that I can get it in small 1/8 NPT size.
I can make a hit and watch my IAT's climb and as soon as I lift, they start dropping and then it will just sit there bouncing around at idle.
My factory IAT would only go up very slowly and it would never come back down until I shut the car off.
Would highly recommend for what you're doing.
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The temp range I will be using the car will be 50*F - 100*F ambient. Couple that with the turbo placement and possible filter right on the turbo it would be sucking in hot underhood air. when the engine was NA I would see 140's IAT temp while cruising. The filter on the turbo is basically in the same place as that setup so 140*F base plus turbo heat plus compression. I'm going to spray wiper fluid no matter what just for the safety. I currently was getting it setup with the 2 GPH Snow nozzle at 100psi but I'm running a 300psi snow pump. If we figure a 60* increase on say 140* that puts me close to 200* then figure the water/meth and probably 91-93 octane. This is a daily driver type car so if I'm not running 87 then going to 89/91 the savings isn't really there and I might as well just go to the 93 if it cost me $5 a week difference to drive the car.
Any experience with the motion raceworks Href Hi temp IAT sensors? I got a new fast EFI IAT but ran across these Href sensors... $80 for a sensor ouch... wonder if its worth it? Reason I like it is for the accuracy and speed but also that I can get it in small 1/8 NPT size.
Any experience with the motion raceworks Href Hi temp IAT sensors? I got a new fast EFI IAT but ran across these Href sensors... $80 for a sensor ouch... wonder if its worth it? Reason I like it is for the accuracy and speed but also that I can get it in small 1/8 NPT size.
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I would run E15 88 octane if you have it in your area. It's a nickel cheaper than 87 but seems to have similar detonation resistance as 93 pump gas. On 87 octane I can only run about 22 degrees without KR. With that E15 I can run 26-27 degrees no problem. Granted this isn't on a FI setup but you get the idea. It's amazing what a little bit of ethanol can do, and it doesn't kill your fuel mileage like Full E85 does.
I run the Rife IAT in my car right now, they're incredibly fast acting compared to factory stuff.
I can make a hit and watch my IAT's climb and as soon as I lift, they start dropping and then it will just sit there bouncing around at idle.
My factory IAT would only go up very slowly and it would never come back down until I shut the car off.
Would highly recommend for what you're doing.
I can make a hit and watch my IAT's climb and as soon as I lift, they start dropping and then it will just sit there bouncing around at idle.
My factory IAT would only go up very slowly and it would never come back down until I shut the car off.
Would highly recommend for what you're doing.
I would run E15 88 octane if you have it in your area. It's a nickel cheaper than 87 but seems to have similar detonation resistance as 93 pump gas. On 87 octane I can only run about 22 degrees without KR. With that E15 I can run 26-27 degrees no problem. Granted this isn't on a FI setup but you get the idea. It's amazing what a little bit of ethanol can do, and it doesn't kill your fuel mileage like Full E85 does.
I had a fast-acting factory IAT sensor in the car previously which they shouldn't be allowed to call them fast acting because they're anything but.
The FA factory sensor wouldn't even reach the same peak temp as the RIFE so with a factory sensor you won't actually see how hot the IAT's actually are unless the IAT's are at the temp for an extended period of time.
Don’t think there is any way for someone to suggest what would work specifically for your setup. From a KISS standpoint, premium fuel seems like a no brainer and all that’s needed for 6lbs. Its better quality fuel all around and probably your best bet. You likely can’t even run peak TQ timing NA on the 87.
At the same time IMO a DIY pre turbo washer fluid setup would cost peanuts. So why no. Prob not something I’d lean on to keep the motor out of detonation if you plan on putting a lot of miles on your setup. Which it sounds like you are since you are wanting to run cheap fuel.
I wouldn’t pay what aftermarkets cost, esp for 6psi. Could literally run a washer fluid pump and 1-2gpm worth of nozzle. You don’t need a 300psi pump or even 250ml which is like 4gph. You will bog and hurt power at those levels. A low pressure pump with a hobbs switch T’d into your washer fluid reservoir pre turbo (I like them in the filter head) is all that’s needed. And all it will do is give you a little detonation cushion.
At the same time IMO a DIY pre turbo washer fluid setup would cost peanuts. So why no. Prob not something I’d lean on to keep the motor out of detonation if you plan on putting a lot of miles on your setup. Which it sounds like you are since you are wanting to run cheap fuel.
I wouldn’t pay what aftermarkets cost, esp for 6psi. Could literally run a washer fluid pump and 1-2gpm worth of nozzle. You don’t need a 300psi pump or even 250ml which is like 4gph. You will bog and hurt power at those levels. A low pressure pump with a hobbs switch T’d into your washer fluid reservoir pre turbo (I like them in the filter head) is all that’s needed. And all it will do is give you a little detonation cushion.
I don't disagree but the speed is of the sensor is very impressive.
I had a fast-acting factory IAT sensor in the car previously which they shouldn't be allowed to call them fast acting because they're anything but.
The FA factory sensor wouldn't even reach the same peak temp as the RIFE so with a factory sensor you won't actually see how hot the IAT's actually are unless the IAT's are at the temp for an extended period of time.
I had a fast-acting factory IAT sensor in the car previously which they shouldn't be allowed to call them fast acting because they're anything but.
The FA factory sensor wouldn't even reach the same peak temp as the RIFE so with a factory sensor you won't actually see how hot the IAT's actually are unless the IAT's are at the temp for an extended period of time.
Don’t think there is any way for someone to suggest what would work specifically for your setup. From a KISS standpoint, premium fuel seems like a no brainer and all that’s needed for 6lbs. Its better quality fuel all around and probably your best bet. You likely can’t even run peak TQ timing NA on the 87.
At the same time IMO a DIY pre turbo washer fluid setup would cost peanuts. So why no. Prob not something I’d lean on to keep the motor out of detonation if you plan on putting a lot of miles on your setup. Which it sounds like you are since you are wanting to run cheap fuel.
I wouldn’t pay what aftermarkets cost, esp for 6psi. Could literally run a washer fluid pump and 1-2gpm worth of nozzle. You don’t need a 300psi pump or even 250ml which is like 4gph. You will bog and hurt power at those levels. A low pressure pump with a hobbs switch T’d into your washer fluid reservoir pre turbo (I like them in the filter head) is all that’s needed. And all it will do is give you a little detonation cushion.
At the same time IMO a DIY pre turbo washer fluid setup would cost peanuts. So why no. Prob not something I’d lean on to keep the motor out of detonation if you plan on putting a lot of miles on your setup. Which it sounds like you are since you are wanting to run cheap fuel.
I wouldn’t pay what aftermarkets cost, esp for 6psi. Could literally run a washer fluid pump and 1-2gpm worth of nozzle. You don’t need a 300psi pump or even 250ml which is like 4gph. You will bog and hurt power at those levels. A low pressure pump with a hobbs switch T’d into your washer fluid reservoir pre turbo (I like them in the filter head) is all that’s needed. And all it will do is give you a little detonation cushion.
interesting... I got a brand new 300psi snow pump for $80 off FB market place. I'm reusing old snow nozzles I had from another kit that I'm not using on my firebird. basically the pump is the only cost and a $25 devils own tank bulkhead adapter which I converted the stock wiper tank with. I was actually planning to run a relay and have the pump controlled by the Holley Term X. I can setup and output pretty easily. Currently using only one as PWM for brushless cooling fan. Are you saying that a 2PGH pump from snow on the 300psi pump will really put out 4GPH? It looks like snow rates them at Boost Cooler Hyper-Sonic Injector, 125ml/min@100psi or 2GPH, this is for size 2. I think the nozzle has the built in check valve as well as I tested it with an air gun. https://www.snowperformance.eu/en/wa...zzle-sno-n0200
I was thinking of tapping the cast elbow right after the BOV for the nozzle, that way it has 18-24" till it reaches the IAT sensor in the intake. I also thought that I would get some wiper fluid spraying out the BOV when it opens and the same if it was in the turbo filter head. Putting it in the filter means the turbo blades could get eaten up but then I would have it definitely coming out the BOV when its open.
this is the setup for the cold side.
Last edited by customblackbird; Jan 14, 2025 at 01:17 PM.