Some will tell you a good working drum brake will hold better than a disc setup. Many upgrade to a larger drum brake. Just fyi.

 

1000?! I think I can hit my goals with about 500 and a decent 60 ft!

Funny on the snap ring. Definitely a mistake I won't make again.

I think I've read that before. The whole drum brakes "bind" up and hold better in a static load argument. I kind of get it but think with enough piston area the disc setup will work better.

If I'm wrong I'll pay the penalty and just get a transbrake.

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A quick update on the rest of the car. The rear brakes are nearly complete. I'm waiting on some shims to come in before a final assembly and bleed.

The intake is also nearly complete. I did the barbed IAT sensor, and welded on AN fittings to make the rail crossover. A couple vacuum lines to hook up and it should be complete.
It's getting warm and I'm itchy to drive this thing!

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Yeah, drum brakes self apply with rotation, there's a term for it, but I don't recall what it is. That said, disc is definitely an upgrade everywhere else.

Can I ask how you mounted your iat? Sloppy method of a drill and a hammer? I have one to do here soon.

 

My old truck intake I drilled and tapped 3/8 NPT.

The NNBS I drilled with a .505" drill bit and sanded the sensor down. The sensor body measured 0.495 with the ribs measuring about 0.530 unsanded. So yup, sand lightly then hammer home. I would've reused the old sensor but I didn't want to drill the new intake out that far.

 

Thanks. I've done the old intake using Matt's method, but haven't tried a nnbs yet.

 

I won't put an IAT in the intake manifold on forced induction applications anymore because of heat soaking and their reliance on knowing the precise IAT when tuned as such. Plastic intakes aren't so bad but in general I place the IAT around the intercooler outlet, way before the throttle body, in an aluminum pipe, with some kind of plastic washer to prevent the two from touching.

 

You brought up a very good point and sent me down a bit of a rabbit hole. I didn't realize how much was calculated off of IAT, but it is a direct input into the pulse width calculation. Heat soak is certainly an issue but it has me more realizing how much the water/meth may be directly altering fueling. Colder air requires more fuel right so hopefully it's at least correcting in the right direction when it sees the lower temps from the methanol evaporating off the sensor.

I'm not going to panic too much since the logs, specifically the 02 sensor, look OK but I'm going to put moving the sensor on my list. What kind of IAT sensor are you using? I'm only familar with the GM sensors with either plastic barbs or NPT threads.

 

I have typical brass IAT sensor from a high quality supplier, EFI source or somewhere similar. Its been 4 years I just bought a bunch of them one time. Just dont buy an ebay unit or chinese unit, get OEM product.

The IAT sensor is a slippery slope of a tuning sensor. It CAN perform many functions in fuel and timing, however it isn't necessary if you know what you are doing to rely heavily on it, or at all if you truly are a master tuner just dyno tuning and paying attention.
--> The primary function of IAT sensing in a daily driver application for OEM vehicles can be quite different than in a high performance car. Not everybody can recognize the difference but as you learn to tune with these sensors more and more you may begin to 'see' how the applications differ,
For OEM vehicles the IAT is more about adjusting fuel and timing to keep things aligned with closed loop, and it performs these adjustments often unnecessarily excessively due to the heat soaking and the way that some OEM ecu work
For example (GM LS ECU) I've noted will pull far more spark and fuel due to high IAT than seems rationale. Following the OEM ecu style of tuning in this fashion will lead a forced induction engine into a melt-down or at best a lack of power and severely skewed fueling in open loop.
By the way I always tune and leave MY personal cars in open loop for various reasons (A. 14.7:1 is neither ideal nor optimal, B. Larger injectors don't play well with the resolution of 'step size' in closed loop fueling algorithms (the a/f tends to swing too far in either direction due to the large adjustments in PulseWidth caused by OEM algorithm closed loop), C. Keeping open loop allows you the tuner to spot areas still in need of adjustment rather than hiding them behind closed loop % automated fueling, Over time your engine will benefit with superior fuel economy and response, and cleaner spark plugs, less carbon deposit, by using more optimal a/f ratios in open loop as 14.8 to 15.4:1)
Aftermarket modern ECU such as HOLLEY Terminator-X do not have these issues with their closed loop because it utilizes a wideband full-time and a target a/f ratio chart. So I highly recommend that system if you dont need the torque management and other bells and whistles the OEM GM ecu can offer, which I could not live without in my daily driver applications, otherwise I would jump to a stand-alone.

Sorry for the text wall but this is all tied to the IAT tuning.
IAT fuel adjustments walking around are compensated for in closed loop at part throttle (which again I do not recommend you rely on closed loop with NARROWBAND sensors) which make them somewhat obsolete. In other words IAT tuning at part throttle is practically negligible if you are using narrowbands because the O2 will simply compensate for any mistakes on behalf of the IAT sensor.
On the other hand, IAT changing your spark timing is NOT in any way compensated for anywhere. So this is really the CRITICAL aspect of IAT tuning that you should nail down long before the engine starts for the first time. In other words, using experience or the help of others with that experience, set your IAT timing compensation up in advance should be easy and fairly accurate assuming the sensor is working properly.
This is extremely easy in forced induction applications because forced induction timing is very low to begin with (often 8* to 18* ranges for mild setups using 93 and E85) and even pulling 1 or 2* from a properly tuned configuration (street cars) can result with a very high EGT and melt the engine quickly. Which is why IAT spark tuning for these setups is so easy: You already know that pulling a bunch of timing is NOT an option for real-time adjustments made by the ECU. Instead, we use small increments, for example:
80*F IAT +0.25*
100*F IAT -0.15*
120*F IAT -0.50*
140*F IAT -0.85*

Something like that, plus or minus around 1.5 degrees or less is typical even for gasoline setups. Thus, the REAL safety in a forced induction setup doesn't come from reliance on some sensor, it comes from YOU. When you setup and dyno tune the car (street cars) you already automatically use the minimum timing that provides a reasonably low EGT and minimum cylinder pressure peak, so when things get HOT they are already tuned to be SAFE and the IAT sensor at that point is just a very slight 'extra conservative' mechanism like a cherry on top of an already safe tune that would have worked fine without the IAT input.

 

So now lets get back to fueling and IAT and methanol.
There are three ways I know of to use the IAT in meth injection setups,
1. spray wayyyy before IAT so the meth and water has a chance to evaporate before it hits the IAT sensor
2. spray after the IAT sensor so there is no influence on IAT
3. Directly wet the IAT sensor on purpose

#1 is not how meth injection was intended to function and you should avoid this situation at all costs. To work best, the Meth and Water must make it into the chamber before it can evaporate. The intended target for water injection is the piston surface, your GOAL is to cool the piston, and the only way that can happen is if you inject the liquid directly near the piston and force it to come close to the piston just as it is evaporating. Due to the modern design of DRY FLOW intake manifolds this can be very hard to achieve, it can lead to distribution problems. Thus I do not recommend spraying large amounts of Meth/Water. Also This means there should be NO IAT DROP due to the meth and water injection. I Realize this goes against all the hype about meth and water but if you do some research on the subject (going back to WWII water injection) you will understand that these aux injection systems were never intended to drop the IAT and indeed can work against you in those situations. For example All gas molecules take up the same space at STP (standard temp and pressure). So water and meth as a gas takes up just as much space molecule/volume as does Air, which means for every molecule of meth or water that evaporates it will displace 1 molecule of air, thus reducing your AIR DENSITY even while the air is becoming cooler. In high power turbo applications this doesn't really cost any power because we can simply up the boost to compensate, but still it defeats the purpose of the injection. There is more but this is already becoming too long so lets move on.

#2 This is how I usually set the systems up. Avoid spraying on or near the IAT so the IAT can do it's job. Tune the Engine so that is the meth cuts off (street cars) There is no engine damage. In other words use NON-meth ignition timing, and NEVER tune the engine to rely on fuel incoming from the meth injection. If you search around you will find that many people have had their meth systems cut off and ruin the engine. This is because besides clogs and check valve failures there is also the issue of PUMP failure, since those pumps are wear items like spark plugs they must be changed as maintenance, and few people realize this until it stop working and ruins the engine. Thus, for street cars, ALWAYS tune off the meth and ONLY use the meth as a supplementary safety feature. If the injection volume and water partition is set correctly it can support additional boost that would ALSO be acceptable when the meth system cuts off, but ONLY for a short time period. In other words when done properly, tuned well, a failed meth system will give you a few seconds to realize the problem and let off the throttle before the engine fails. This is possible because you used a NON-meth timing profile and you DIDN'T rely on the meth to hold down the air fuel ratio.

#3 is more for race cars, with cheap owners who don't want to spend $$ on E85 flex fuel setups. This is for your $500 engine making 1000rwhp on a $2 budget basically. Avoid at all costs on street cars. However if you decide to go this route, the idea is spray on the IAT sensor and witness a large "fake" drop to IAT. Then Tune the engine so that if that "fake IAT drop" disappears, there is an alert and the engine goes into some kind of "limp mode" or is tuned super rich with no timing so it just coughs instead of blowing up. In other words this situation can function, in theory, as a sort of safety kill switch in the event Meth stops wetting the IAT sensor.

In theory, #3 could work well with #2, if you have two IAT sensors in play. One of them detects meth the other detects actual IAT. You'd place one IAT just before the meth near the intake manifold and another just after it. But this seems overly complicated and excessive to me (I like minimal equipment)

Finally briefly I want to touch on meth and water.
Water is more potent than methanol at lowering temperature. It has a much higher heat capacity. It will cool the piston and cylinder superiorly.
Water is also more available to the cylinder in liquid form, it is harder to evaporate than methanol.
Water is how these aux injection systems were originally intended to be used. People just started adding methanol later because it is miscible and functions well as an octane booster.
The ratio of water to methanol is just as important as anything you tune inside the ECU. I recommending using as much water as possible even 100% Distilled is ideal because it cools parts superior, it is safe to spill and touch.
--> Unlike methanol. Methanol turns to formaldehyde when it comes into contact with the enzyme alcohol dehydrogenase which is present in the human body. So if you touch or inhale methanol it will quickly start to kill and immobilize human cells and structures, leading to serious consequences. Meth also burns with an invisible flame and can form explosive gas pockets within the engine bay if it leaks. So it's kind of like playing with a liquid toxic fire.

That said, meth is an incredible octane booster when mixed into 93 octane. It's basically like adding unleaded racing fuel to the fuel tank. This is your 'safety net' and why I still recommend using some methanol even with all of it's potential issues.

As to tuning with meth. For street cars (traditional 18-25psi of boost max V8 setups up to approx 800-900rwhp is fine) trying to avoid flex fuel (the only reason you should reach for meth is to avoid flex fuel setup) always tune the engine to NOT rely on the meth as a fuel source. Typical injection nozzle size and rate is fine for this anyways.
For example, Most moderate/low compression engines will run just as well at 11.1 a/f as they will 10.9 a/f, or 11.2 compared with 10.8, there is some margin for error there where with and without the meth injection will have no influence on the torque or power of the engine. And since its a street car you will NOT be wanting to add timing or remove fuel to compensate, because
A. this will only squeeze the remaining 5 to 7% of torque and power from the engine (not worth the risk on street cars)
B. when the meth pump fails you will have too much timing and not enough fuel = boom

If you'd like more info for meth injection or anything I wrote about let me know I have tons of information available for reading

 

Also I forgot to mention how IAT fueling "should work" and the "reality" of how we should use it for high performance cars.

In OEM applications IAT is used to pull fuel for very high/HOT IAT because when the IAT goes up, air density drops, so less fuel is required in theory.

In high performance applications you will do NO SUCH THING. Instead, you will define a ZERO location (say 80*F is ZERO) and on BOTH sides of that zero you will be increasing fuel.
For example
25*F +8% fuel
50*F +6% fuel
80*F +0% fuel
100*F +2% fuel
120*F +4% fuel
140*F +7% fuel

Notice we add fuel BOTH ways. This is because higher IAT should be compensated for with a richer fuel mixture in forced induction applications to help cool things down, even if the tuneup becomes slightly richer this is how we use IAT as a safety feature.
Also notice there is MORE FUEL being added for COLD situations, always get slightly richer as the IAT drops to compensate for the extra oxygen that should be coming in along with cooler air.

 

Sir I feel mildly attacked with this statement haha. I didn't actively plan for #3, it happened more by accident but it is a nice feedback since I'm watching IAT on my dash that the injection is working. Your point about tuning to run safely with or without it kind of makes that a moot point.

The more fuel / more fuel part is interesting. I wouldn't have expected that. My takeaway from this is to spend some more time familiarizing myself with what my ECU is actually doing. Thanks

 

Hey I am sorry about my wording, I just write the stuff fast without thinking. Nothing I write is ever meant as any personal attack, I only try to word things to get the idea across with as few words as possible because of the sheer volume of information.

Everything I write is from the perspective of street cars, not race cars. So when I make a point about a race car, its to show the polar opposite of what a street car would want.

You really have to choose 1 or the other. Street or racing. They are very different.
I should define racing. Racing is a competition status where your winning or losing may depend on a lot of money or being fired from the racing job. In other words, in the majority of racing situations, you need to win or you will lose your car or alot of money. So that is why I phrased it like that, "race cars... cheap engines... save money " I made the assumption that somebody trying to win a race with their car on the line "pinks" Would want to both use the cheapest engine, avoid expensive fuel system stuff (93 + meth is like a $250 fuel system where E85 flex is like a $2500 fuel system, x10 cost and maintenance) and still keep the engine in 1 piece by the end of it.

I hope that kind of clears things up here. I've been making the assumption the entire time that you are not trying to win any money or win any cars, you are not willing to risk an engine over a win or loss. That is what takes you from racing into street car territory I believe it is the overriding factor anyhow. Race cars may be tailored and trailer'd to the track, lack overdrive, etc... but mainly it comes down to whether you are going to win some money or not, at the risk of your car and engine parts that decides how you tune and how far you are willing to go (2-step, nitrous, hard on the parts but can win you a race).

So from the top to the bottom I assumed you prefer safety over winning. Keeping the engine alive over getting ever last ounce of power out of it. Makes sense I hope....

So why is wetting the iat a "race car" feature. From the perspective of cheap engines and potentially losing your car over a race, this is simply the cheapest safety net you can install when using methanol and increasing boost to take advantage of the octane rating increase. Which in and of itself is NOT a street car feature or street car situation since it puts the entire engine/turbo at risk.
(you blow the motor it sends metal to the turbo... possibly) so I define it as a racing situation *only*.
But why else do I say that?
Because on the street, you will see normal IAT when the meth is off. And a normal IAT cannot be used easily due to the way the engine is tuned to expect an artificially low IAT.

For example, you tune the IAT so that when it reads 60*F (meth active) normal timing is used and normal fuel.
But when the IAT reads 85*F at WOT, which is a perfectly natural, normal IAT for properly intercooled turbo cars in fair weather, you MUST tune the engine so that it will ALERT THE DRIVER that the meth isn't working. So you can never drive the car on the street in regular IAT temperatures if you are depending on the IAT to warn the driver.
In other words, while driving around normally on the street, a street car will go 80% throttle, or 50% throttle, it may see a couple PSI of boost at part throttle, you know getting on the highway or whatever. And in those situations the meth will be OFF and the engine will fall on it's face because you've tuned it to do exactly that- when the meth is off it should warn the driver by making the engine run safely and poorly, to alert you the meth isn't wetting the sensor.

That is why it becomes a racing only feature, you would never expect to see 80*F or 100*F IAT unless the IAT stopped getting wet with meth, and these are TYPICAL IAT for street cars with proper intercooling, perfectly safe when tuned properly but no good for a race car where the meth has failed and the extra timing isn't warranted.

Sorry if that sounds convoluted. One more time.
Race car: You add torque and power by squeezing the engine's timing and fuel profiles for every last ounce of power, and boost the octane using meth, and the car only runs at wide open throttle. It does not have overdrive or hit the highway or anything a street car might do frequently. Overdrive is not wanted or needed in 1/4 mile racing anyways. And when the meth shuts down, the engine WOULD explode, but it does NOT because you have it tuned so that when the IAT hits "normal temps" of 80*F 100*F the driver becomes alerted and the engine falls on it's face immediately to protect itself from the racing tune profile.

Street car: You removing timing and run a richer than necessary a/f ratio to keep the engine safe in daily driver traffic situations, such as high IAT. The high IAT therefore does NOT alert the driver, and does NOT prevent the engine from running properly. This is why wetting the iat sensor becomes a huge problem in a street application.

 

A little progress over the weekend. I snuck out long enough to pretty much finish the intake swap and fire it up. I still need to make the fuel rail spacers but otherwise I think it's ready.

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The rear brakes are done and ready to be bled. I'm more than ready to drive it again.

And if you want to see a short clip with bad audio of it running:

<- it sounded better in person. The acoustics and microphone are shit.

 

Remember to perform the critical pressure test before any boost, please read
https://www.theturboforums.com/threads/1998-s10-on-twins.387315/page-2#post-2045047

It sounds good, also remember to use an air filter and protect your turbo and engine.
I recommend AFE paper air filter, reusable and high quality.

Air is filthy, even while clear. The small debris will pit metal materials and embed them, it will cause imperceptible damage to the compressor wheel and the piston/cylinder wall that rapidly degrade the quality of engine health and longevity.

 

A long update with some good and some bad...

So the rear brakes are done and the system bled. I bought a Motive pressure bleeder with the adapters for the Chrysler master cylinder. Best purchase I've made so far! The calipers took a long time to bleed and the wife was in no mood to help push a brake pedal...

So on Sunday everything looked good and I went for a 3 mile drive to the gas station. All good until it wouldn't start. It would fire and then immediately die. I wiggled some stuff and found a loose ground (coil pack to cylinder head)... I tightened that but no change. That's when I noticed the map sensor staying pegged at full vacuum.

So I had it towed home and a new sensor has been ordered. Maybe I should order a spare too. I'm assuming the loose ground caused a spike that fried the sensor. The ground and +5v signal are shared with the TPS and I see that moving correctly, so I'm fairly certain it's not wiring related.

At least the brakes worked great ugh, some serious love hate with this car sometimes.

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Shit happens man, early in a build its normal to occasionally come home under some other vehicles power... more than once, don't let it discourage you! Eventually you will get to where the car is straight and that doesn't happen -- 'til then enjoy the gamble!

 

I got the tow of shame the other day. Lucky I was still in the Subdivision so my wife drug me home with a strap. Mine was self inflicted wiring, but it got me thinking I should probably have some spares. I am thinking a MAP and TPS, what else do you keep around (glove box) for just incase?

 

Hopefully somebody else weighs in. I just had a crescent wrench and zip ties, look how far that got me!

I'm leaning towards a MAP and TPS as you say, and some more fuses. A crank sensor would be more than I would be able to do with the minimal tools on hand. Any other sensor failure and my setup would still run I think.

 

What quality of parts? I don't think it's that uncommon to have a China map, or tps go bad, but would expect an oem to go a few miles without failure.

 

Well mine was an EFI source MAP (so China? Not sure) and a OEM tps. Pretty sure my issue was self inflicted though too so I would tend to agree on them lasting. My complaint is waiting 3-4 days for a replacement.