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FD OEM FPR limitations and track build reliability
Does anyone know what the limitations are of the stock FD FPR? What happens if those limits are exceeded?
I'm going to run a direct relay to a 340L p/h fuel pump (other fueling is stock; rails, injectors) but wasn't sure if the additional flow is going to be an issue.
Also curious what additional modifications/tuning people have added in order to have a "reliable" tracked FD and other upgrades that people have found significantly improved the car from a driving perspective. A specific question is:
-Meth/Water AI: From my limited knowledge, throwing meth/water without a tune into a car will result in significantly decreased power. So to take advantage of AI, you would need to advance timing etc. However, since I am on a PowerFC, I am unable to take advantage of the AEM BoostSafe function, that can pull timing and "limp" mode the engine if some part of the AI fails.
Is it possible to have a tune that's safe in case of failure of the AI system? I'm imagining a worst case scenario of an undetected and unalarmed failure that cuts off the AI completely during a WOT run down a main straight somewhere, where I might not catch it via the diagnostic LED or even at all.
Just for reference, my power goals are anywhere from 270 - 300 to the wheels, leaning toward the lower end if 300 is significantly less safe.
Other car setup:
-Battery relocated to bins
-Ohlin
-Superpros all around, Jauto pillowballs
-Banzai poly engine mounts
-Stock wheels on 225 RTK615K+s (planning on moving to 255s on 17x9.5 wheels after tuning)
-race seat and wheel for leg clearance
-Banzai trans brace
-Carbotech xp10 fronts, xp8 rears
-howard coleman suspension settings
Open to suggestions and improvements on the build, thanks!
Man, it's like looking at a past version of me!
If you can afford it (and the person tuning your car can do it), upgrade to a late style CANBUS ECU and display i.e.: Haltech, etc. Using methanol, or a mix, depends on 2 things: 1. Your tuner, and their knowledge of adding the system. 2. Your interest in adding that system and the "ritual" that comes with it. I have a 50/50 water/meth injection system, and I'd prefer not to. I need to store a 5-gal container of that crap, and mix it when I need more in the car. More modern ECUs can include failsafes and shut-offs to get around the need for methanol. Again, this is primarily based on your tuner's abilities, unless you are in a position to choose any tuner you want in all the land - then it's personal preference.
Good suggestion. I think the ECU overhaul would be the next big thing with a legit harness refresh.
Hopefully the older version of you didn't blow any motors XD
The meth system is already in place and i dont mind lugging bottles of it around. I was initially attracted to it purely for the decreased charge air temps and combustion chamber cleaning. I figured that running it would be MORE safety on top of a conservative tune, but didn't recognize the decreased octane of the fuel would result in significantly less power. I'm not sure who is super familiar with meth tuning in NorCal but I did reach out to sakebomb for their input since they'll likely be tuning the motor
First off, you are looking at very modest amounts of power. The Walbro 255 is all you would need.
The stock FPR is good for pretty much anything you can do with the twins. That won't be an issue. Worst case your fuel pressure will spike high, making the car run super rich, if you run out of capacity.
You are over-thinking the AEM system big time. Use a medium nozzle in the TB elbow with windshield washer fluid. Done. Don't tune for it, just let it cool the charge down. I've been running like this for 10 years with zero problems. Don't try and mix exotic stuff for the AI system, just use plain blue windshield washer fluid. I draw from the stock washer fluid reservoir and I can go a whole trip to Deal's Gap and back without having to touch it.
A good moderate water injection setup just makes your car run like it's a cool day. Also keeps the engine much cleaner inside.
This thread is the gold standard on making good power on the twins -
I definitely am over thinking the AI having fallen down the google/youtube rabbit hole looking into methanol injection in general and then tuning and then how it even works.
My last tune minus the oil cooler, v mount, ignition and fuel pump was very limited even with distilled water AI due to the stock IC. IATs were the limiting factor there (60c on the dyno, and I swear I've seen it hit 80c on track). That Banzai thread is finally relevant for me now that I've got the proper cooling! Once I get tuned I'll throw the numbers back into here just as a reference for posterity.
You can do a lot with AI, that is definitely a deep rabbit hole.
My statement is from my car and friend's cars with real world street driving experience. Power difference (as far as losing power) isn't measurable on the butt dyno as far as a reduction in power, if anything the car seems quicker and more responsive - again, it makes the car run like it's a cold day out.
One of my friends (Kurt) went back through his engine after running water injection for quite some time. The rotors needed a spray of brake cleaner and a rag to get the carbon off, not soaking or grinding to get a thick coat of carbon off.
Don't go nuts, run blue windshield washer fluid and a basic medium nozzle on an AEM kit. IMHO this should be standard on any RX-7 - inexpensive to add, keeps intake temps happy, keeps rotors clean.
Curious what you guys ran for the controller settings (amount of flow) with the AEM medium nozzle kit for windshield washer fluid.
I have the medium nozzle as well.
For those uninitiated, the left **** chooses the boost PSI that starts the AI.
The right **** indicates the boost PSI that would result in maximum flow. So the flow magnitude is supposedly linearized between the two boost numbers.
For water only, I think Sakebomb initially had it at 4 PSI starting and then 20 PSI ending. Meaning that we only get a bit under half maximum flow at full boost on the twins (10 PSI).
As has been said, you’re power goal isn’t hard to get to. It'll still be fast but can be done at stock boost with bolt-on’s and will be key to the other goal…reliability.
Re: AI, this might help: https://www.rx7club.com/auxiliary-in...ion-fd-959565/
Its mentioned late in the thread but using Howard Coleman’s formula from the stickys 300 whp takes an M3 nozzle on (IIRC) a 150 psi pump , NOT the M5 I mistakenly listed initially.
I just run distilled water for the street. I did a track section not long ago and preferred to use Boost juice over washer fluid for that. A gallon went a long way so the cost wasn’t an issue.
I am at the beginning of exactly what Keith laid out there on moving up from the Power FC to a more modern Elite, and adding in fail safes with a few things including WI. I will admit I am at the beginning phases of my own set up gantlet and am working through it all theoretically. This thread here might help add some more insight
Also FWIW, I am upgrading my WI nozzle to a V3 for a broader spray (more info here
Sounds like you have a really solid build going so far zli agree with Dale, your power goals with what you have are easily attainable. You could probably even dial back the aggression on your tune for longevity if you'd be happy with a potent 300whp
I also agree that a Walbro 255lph on factory injectors should suffice (FWIW I ran the 255 for track duty with 550/1200's without issue). One thing I would recommend is a solve for fuel starvation in hard cornering. Something along the lines of the Hyperion-based Garage Alpha fuel baffle or a Radium surge tank if you have other modifications in mind while you're at it
Let's see this FD - I love your style and commend you on your moxie
Last edited by ZumSpeedRX-7; 02-26-22 at 12:20 PM.
Thanks for the suggestions! Those are some very useful threads.
For what I'm trying to maintain, it seems advancing timing and being aggressive with the AI won't be necessary. When I get retuned I'll be sure to implement everyone's suggestions.
I went with Raceonly's fuel pump (340 lph) because it seemed to have the best drop in solution (for dummies like me).
I really would love to invest in a Haltech or other more modern ECU but I feel like that's a huge step and would result in dreaded project creep. Ive always wanted to get my harness completely redone as well, there are too many broke connector clips and rock hard electrical tape. The current goal is to make events in mid/late April and really put the v mount and water/meth to the test at Buttonwillow during the summer.
the v3 nozzle looks great but unfortunately my current v2 is JB welded to my OE intake elbow 😢
I do have a Greddy elbow but ill wait to see if the KS V mount is sufficient or if I'll need to go even bigger to keep temps under control.
I am absolutely horrible at activley taking pictures of the car other than when I'm referencing it for fixing but here it is at Buttonwillow, thill a year and a bit ago and the condition its in now 🥲.
original plan was to throw the rep GTC bumper on, get some skirts and a diffuser with a APR or something or another wing and wrap it all yellow. But realized that's way too much money on stuff that won't get me anywhere near a track. So failing clear coat montego blue FD it is for now so the only major purchase holding up everything is a set of wheels!
Not related at all but getting 1 year old dust off the diff while doing the bushings was extremely satisfying. I didn't know they came black from the factory 😅
That differential really cleaned up well. I’d be happy too. I changed diff bushings a couple years ago and the hanger was pretty dirty too…along with a small area of corrosion where water can sit. I used some POR15 on it.
For 300 whp at stock boost wouldn’t the stock injectors he mentioned in the first post be ok…with a fresh and up-rated pump?
Just wanted to drop an update with, hopefully, the final changes for the car for a while:
-Ended up going with just water AI, the Knight Sports V Mount has helped tremendously with temps overall. Also cut some holes in a spare hood I picked up and I think that helped with heat as well.
-Made 275 to the wheels. DK from Garagelife said we could have made around 300 easily with more boost but the BNR wastegate actuator was preloaded and opening early. I contemplated getting some additional dyno time but honestly, 275 is enough for me and so took the excuse and called it there.
My first day out will be in Oct and the car seems to be working well with the updated parts, though still some minor gripes:
I think I amrunning very rich or something because my oil filler neck and catch can consistently smells like gas after a drive. I'm having a sample of my oil sent to blackstone for analysis to see if it's dangerous.
There's a metallic clinking coming from the rear that I've traced down to the trailing arm to LCA pillow ball. I'm hoping it's not the pillow ball actually failing but will need to play around with the torque specs to see if that alleviates the noise.
Rotaries dilute fuel into oil a decent amount, having a gas smell to some extent is normal. It's more so if you are really rich. A tight, new engine can help some with that. But, that's why you want to run heavier oil (I run 20w50) and keep up on 3000 mile oil changes IMHO.
Also, the hose clamp on the hose going to the brake booster looks like it's not seated, make sure those are on properly. If that hose comes off you will have a Bad Day.
The IC looks really sharp, how was that kit to install? Price and availability?
Clean setup. A strong 275 is great power on a stock-ish setup. What boost were you up to? What boost controller? Some folks change the actuators for heavy duty, but normally for more than 15psi. If you were leaking boost at the coupler, that might explain the weak-seeming actuator.
Rotaries dilute fuel into oil a decent amount, having a gas smell to some extent is normal. It's more so if you are really rich. A tight, new engine can help some with that. But, that's why you want to run heavier oil (I run 20w50) and keep up on 3000 mile oil changes IMHO.
Also, the hose clamp on the hose going to the brake booster looks like it's not seated, make sure those are on properly. If that hose comes off you will have a Bad Day.
The IC looks really sharp, how was that kit to install? Price and availability?
Looking good!
Dale
thanks Dale!
i had reverted from 20w-50 because I thought it was causing my BNR leaks but with the oil feed regulator, I'll probably go back.
The kit is the Knight Sports V mount bought off a local. Not sure about MSRP and availability. Very trivial to install and built around being bolt in and OEM+. There's a great write up on the board. I also don't have AC which simplifies the process a lot.
I made something that resembles a duct for it:
Clean setup. A strong 275 is great power on a stock-ish setup. What boost were you up to? What boost controller? Some folks change the actuators for heavy duty, but normally for more than 15psi. If you were leaking boost at the coupler, that might explain the weak-seeming actuator.
I think it was somewherr around 12 or 13, not 100%.
It's just the stock MAP sensor.
I'll keep that in mind. I do trust DK to have done due diligence in checking the setup during tune
Got back from the first track day. Ran a couple 2:05s in the morning session at Thill East Bypass while I was still feeling out the car (was scared braking into every turn since I no longer have ABS and a roughly setup brake bias valve). Later in the day, ambient was up to around 95F and I didn't improve on time, just hit a couple more 2:05s. The Vmount worked great, I could go most of a session even in the hotter part of the day and only need to take half a cooldown lap before it drops down to mid 80C from the highest point around 90C. IATs were relatively high even with the AI but I think with ambient being so hot, it was inevitable, during the hottest parts of the day they would fluctuate between 45 and 55C. Oil temps with my dual 25row mishimotos were great all day.
Some immediate quality of life things I definitely need are some kind of fuel baffling (I picked up the Garage Alpha cover at track). I would go through at least a quarter of a tank in a single session when the air is cool and the next 20 min session, I would experience fuel cut going up and down elevation. Later in the day, when IATs were up and I was using less fuel, I could go a couple sessions before needing to fill up but at around 6/10 on the fuel gauge, fuel cut would start.
Brakes were also a concern. Definitely experiencing some fade later on in the sessions which was not confidence inspiring coming into turn 1. Currently on Carbotech XP8s with Motul RBF600 but might move to a different compound, maybe something with a bit more bite. Will see how it goes before looking into a stockish BBK like the Stoptechs.
I was considering getting a set of RB Sways but I honestly don't know what it would do for the car at this point. I'm not sure what I need so I'm going to keep the stock sways for now with the Ohlins.
I switched to walbro 340lph so I could use holley hydramat and the fuel pump over ran the stock pressure regulator causing a rich condition (rom tuned ecu)
If you are tuned for your current fuel pressure you wont have this issue.
I will be removing the stock fuel pressure regulator and putting in an aftermarket fuel pressure regulator to solve my fuel pressure issue.
….IATs were relatively high even with the AI but I think with ambient being so hot, it was inevitable, during the hottest parts of the day they would fluctuate between 45 and 55C….,
If it’s water-only and the nozzle pre-TB, your AI system may not do a lot for IATs. Methanol mix is more efficient for IAT. The water isn’t as efficient and likely doing more to help reduce load on the engines cooling systems (i.e. coolant and oil). And those look to be pretty solid.
I switched to walbro 340lph so I could use holley hydramat and the fuel pump over ran the stock pressure regulator causing a rich condition (rom tuned ecu)
If you are tuned for your current fuel pressure you wont have this issue.
I will be removing the stock fuel pressure regulator and putting in an aftermarket fuel pressure regulator to solve my fuel pressure issue.
Actually, I am on Raceonly's 340 LPH pump, directly wired via relay and was worried about this very thing, the stock FPR not being able to handle the additional flow from the bigger pump and more constant voltage.
I'm noticing a pretty strong gas smell from my dipstick so have been running 20w-50 to try and compensate a bit for any loss in viscosity. I had blackstone take a look at a sample when I was still on 10w-30 but it came back with nominal for gas contamination, though that oil was only used for the dyno tuning session and maybe around 150 miles of on road driving.
My tuner didn't say anything about the pump and it idles well.
If it’s water-only and the nozzle pre-TB, your AI system may not do a lot for IATs. Methanol mix is more efficient for IAT. The water isn’t as efficient and likely doing more to help reduce load on the engines cooling systems (i.e. coolant and oil). And those look to be pretty solid.
Makes sense. I was tempted to go meth but with the PFC, there would be no fail safes. I have an indicator light setup for when the pump comes on but otherwise, I'd be at a single point of failure if I tuned for meth. I started another thread about this and the general consensus seems to be that there's not really a way to have an "ambiguous" meth setup, where the engine can take it or leave it
02-23-22, 03:12 PM
agree with Dale, your power goals with what you have are easily attainable. You could probably even dial back the aggression on your tune for longevity if you'd be happy with a potent 300whp
