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what's up with this site ...can se your comment in 'live feed ' but can't see it when I open the thread?
Not sure....
Update: I am convinced that my exhaust system is holding me back as I noted in posts above. Its mainly a 3" from start to finish and the wastegate is recirculated. I know that the mid-pipe flanges are necked down to 2.75 in some areas. From what I have read, anyone looking for 500hp and above should be a minimum 3.5" and even 4". To redo my entire exhaust system from 3" to 3.5" or 4" is a big task since I have to make everything myself custom. So I figured the first step in reducing back pressure would be vent the waste gate instead of force-feeding the 2" dump (50mm gate) into a 3" exhaust. If I could see improvements in the logs from this it would give me some excitement in making a new exhaust. Well this morning I did just that. I removed my down-pipe, fabricated a dump pipe, and sealed my downpipe where the previous waste-gate entered it..... Pics below
Took it out for a drive and the first time the gate opened up... Holy **** it was like the loudest swarm of angry bee's coming from under my car. It is stupid loud, but only opens up at 12+ psi so unless I am racing the car it is relatively quiet. I figured with the reduced back pressure on the turbo, I reduced the duty cycle to 56 (down from 64). So i took the car out to Interstate Dyno for a pull and got some promising results.
Ambient 65 F (somewhat dry for Florida)
Air/Fuel ~11.4:1
Leading timing 9-15, Split 10
Duty Cycle 56 (22-24 psi)
Delta RPM Rate 934 RPMs/S, which is a 3rd gear acceleration of 11.68 MPH/S
With the car buzzing away, I saw a significant increase in acceleration and jumped liked a MPH/S from previous logs (that were on colder days). This was all done with less wastegate duty cycle because of the less back pressure. I can't wait to get some more data with the exhaust like this. It feels like I picked up 10% horsepower...
Last edited by strokercharged95gt; 01-06-2019 at 01:34 PM.
Nice results! I Wanted to do a dump tube first but everyone i know told me it would be insanly loud so i recirculated. My power goal is pretty much achieved so i dont think ill do dump anytime soon but its good to know theres a major increase!
Nice results! I Wanted to do a dump tube first but everyone i know told me it would be insanly loud so i recirculated. My power goal is pretty much achieved so i dont think ill do dump anytime soon but its good to know theres a major increase!
It is insanely loud. I am looking to add a 24" glasspack and reroute the wastegate dump to see if I can cut the noise down. I think if you have a true 3.5 or 4" exhaust you probably won't pick up much (if any) going to a dump. But when you have a exhaust that is 2.75-3" and the wastegate (2" of high pressure hot exhaust) is recirculated you just create all sorts of restriction and back-pressure that just kills top end. Being that I am bridge-ported, you would think I would have the most power from 7-8k, but it always seemed like I was running out of steam by 7k. I think maybe this may bring some power back above 7k. I will have to get some EGT data and more pulls to confirm that the excessive back pressure was causing it.
Here are some pictures of the hall sensors Andy had recommended. I could only find one but I'm pretty sure I have 3 others around here if you want them.
I read that if you split a reluctor signal that it can't degrade/deform the wavelength and the computer may have problems reading it. I don't want to cut into the factory harness and damage the ABS wiring so I have ordered a used sensor on ebay for $15 that I will install and directly splice into from Adaptronics. If I still can't read that signal, my next move will be to try and install a hall effect sensor in place of the ABS sensor and run that signal into the select unit. It sucks because both of these methods would mean that I lose ABS and my ABS light would remain on. If I can't get the OEM reluctor to work, I will buy one of those hall effect sensors from you and try that. It sucks I have to give up ABS for traction control/launch control. I will keep you all posted.
It is insanely loud. I am looking to add a 24" glasspack and reroute the wastegate dump to see if I can cut the noise down. I think if you have a true 3.5 or 4" exhaust you probably won't pick up much (if any) going to a dump. But when you have a exhaust that is 2.75-3" and the wastegate (2" of high pressure hot exhaust) is recirculated you just create all sorts of restriction and back-pressure that just kills top end. Being that I am bridge-ported, you would think I would have the most power from 7-8k, but it always seemed like I was running out of steam by 7k. I think maybe this may bring some power back above 7k. I will have to get some EGT data and more pulls to confirm that the excessive back pressure was causing it.
I went through all this when I fitted the dual exhaust (seperate wastegate pipe) . I had to do quite a lot to get the noise of the WG down to a level that I was happy with.
Well my little experiment was a failure. With extending the dump tube and adding a glass-pack almost 0 difference in wastegate sound. Looks like I will be making a 3.5" mid-pipe that I reroute the dump tube into. I will try and put a 3.5" resonator on the first section of mid-pipe and a 3.5" muffler on the second section of mid-pipe. I already have another 3" resonator on the catback and of course the 3" HKS Hipower.
Here is a waste of $40 in materials and a Friday night.....
Similar resonator to mine .... I found it was too loud with just that one and a full length pipe . Added one more close to the exit and that did the trick ....louder than the other pipe but really aggressive sounding when you get on it .
you obviously have the skill. Just route your dump back in after that resonator.
I can say this though...DO NOT go straight pipe. All my friends love the 3.5inch turbo back I have but I hate it. there is not "tone" it's just LOUD
you obviously have the skill. Just route your dump back in after that resonator.
I can say this though...DO NOT go straight pipe. All my friends love the 3.5inch turbo back I have but I hate it. there is not "tone" it's just LOUD
Yeah I will try that next. Before I had the hot gasses going into the downpipe 6 inches after the wastegate. This way there is a good 3 feet for the gasses to cool before going back into the exhaust, and allowing the down-pipe gasses about 4 feet to cool before they all meet up. I already have enough 2" tubing just need to order a 2" v-band flange kit should only cost about $25 to give it a try.
Still waiting on my OEM ABS reluctor to get here to try and see if I can get launch control to finally work.
Leading plugs have fouled out this weekend, only lasted about 3 months and a thousand or so miles. I am running heat range 10s all around. The leading plugs were brownish and the trailing were light tan. It looks like I may be slightly too cold on the leading and too warm on the trailing. I will be trying a heat range 11 in the trailing for safety. I am hesitant to go down to 9s in the leading and will just change them more frequently for safety. The cooler E85 maybe fouling them quicker.
Had some fun in the car last night. Got caught up in some shenanigans and did a few pulls one may have been against a SRT Challenger.
Temp was like 55-60
3rd to 4th gear pull (let off early at 7,100 in 4th gear)
No EGT data
Duty Cycle was 54, boost 23-27 psi
Leading timing 10-12 Degrees with a 10 split
Ethanol Content was ~62%
IATs 80-125 F
Injecting 500 cc/min of water and 500 cc/min of methanol
Air/fuel was around 11-11.5:1 even though the car makes best power around 12:1...
I am about out of injector (dull yellow line), there are times were I see all of the injectors (1000/1000/1650) maxed out. Luckily, when my injectors are maxed the A/F is still rich.
Car was accelerating at about 7.3 MPH/S in 4th gear (6k-7k) not much data in fourth, but during my 116 mph trap 1/4-mile time I was getting a 5.8 MPH/S acceleration in 4th gear (6k-7k). So the power is definitely up (higher boost, leaner A/F, less exhaust back-pressure)
Car is still to loud, waiting on parts to correct.
Last edited by strokercharged95gt; 01-19-2019 at 09:32 AM.
Pre-turbo injection (wet compression) is supposed to make the turbo more efficient, remove heat, shift the compressor map over to the right. I can't vouch for any of this as I am not an engineer. There are a bunch of papers on wet compression and the effects on compressors....
Also use it to keep the intake temps lower and give me some extra fuel.
It was already installed and running when I switched to ethanol so it was easier to leave it.
I have read that before. I have a 500 ml/min nozzle pre-turbo and a 500 ml/min nozzle in the Greddy elbow. I am running 50:50 water/meth in a one (1) gallon tank. So I am shooting a 50:50 mixture at both locations.
I am current setup to begin linear injection at 11 psi with full injection by 27 psi.
So I assume total injection is 250 ml/min at 15 psi, 500 ml/min at 19 psi, 750 ml/min at 23 psi, and 1000 ml/min at 27 psi.
One nice thing about having the water/meth injection is that I can ride around for an hour and my UIM temps will be heat-soaked at 120 F. I can then press the test button on the controller and hold it for 2 seconds, release for 6-7 secs, hold for 2 secs, etc., and after a minute of doing this my IAT sensor at the UIM will be just about ambient temps (sometimes a drop of 50 F). I have done this before and shut my car off and touched my UIM and it feels like the car hasn't been running.... I'll look for a log of this or make one the next time i'm about to show the cooling of the top end of the motor by doing this trick, its like icing your manifold while you drive.
Well the motor is hurt. Luckily for you all I have a time-slip, log, and movie of the motor breaking.
Went to the track this morning to get a few runs in. Temp was about 60 degrees and dry. I actually turned the boost down a bit (22-23 psi) for the first shakedown run by reducing the duty cycle in 4th gear. Tried leaving at 5,500 and pedaling it and not using launch control (still waiting on a pigtail). Had to pedal the car through a lot of wheel hop, which again shook the radio face-plate off the radio unit. Car was pulling great until about about a quarter of the way into 4th gear and the car got some massive knock. With my super loud wastegate, I could not hear any engine noises and only knew of a problem when I ran out of power the last 300-400 feet when the car laid over. I could hear my exhaust rattling on the return road. Motor has 0 vacuum, but will start and drive haha. Car has no power once driving. If you listen in the video you can hear the wastegate screaming in 1st, 2nd, and 3rd, and in 4th you can slowly hear it shut as the boost falls and the systems tries to compensate for the boost drop....
When the motor went the air/fuel was 11:1, fuel pressure normal, boost 20-22 psi, leading timing was 11-12, and EGT never exceeded 1600F.
It really sucks because the weather was perfect. I easily had a trap speed of over 120 with a 97 mph 1/8th mile. The formula people generally go by is 1.26 x 97.13 (1/8th mile MPH) = 122.4 MPH. Even with the motor dead the last 300-400 feet, the car still ran a 12.49 @ 113.6 mph. I was running down a modded 392 SRT Charger with a 8 speed automatic near the finish and lost that too.
Oh man ..sorry to hear that . Seemed like you have everything in place to avoid a big det. No clues as to what happened in the logs ?
Spent the last hour checking the motor out. Compression is good (three equal pulses, 100 psi rear, 95 psi front)!!!!!!. Found one bad trailing coil with HEI checker (firing sporadically), but that has nothing to do with it.... And for the grand finale.... I found that I blew a big vacuum line off underneath the intake manifold. It was the vacuum line that fed the distribution block so nothing was getting a vacuum signal. When that happened at 115 mph all of the fuel being delivered got dumped in the motor which bogged it which was likely responsible for all of the rich knock I am seeing in the log (red line). A/F dropped to 10.1:1 at one point. Boost cratered because the manifold was depressurized. The car proceeds to have 0 vacuum and barely run. I quickly looked under the hood and saw nothing, checked the logs, saw all the knock and assumed the worst... I have never been happier to spend $30 to get 3/4 of a run. Car should be okay!
I think a 100 mph trap speed in the 1/8th mile may be done on 24-25 psi...
Last edited by strokercharged95gt; 01-20-2019 at 02:56 PM.
Just a brief update. Haven't had the car out much since I took it to the track last month. New differential bushings are in and I am not sure they will help that much.
I think the problem with wheelhop/clutch/drivetrain issues are that the rx8 driveline is simply not meant to take the shock I am putting through it when launching with a race style clutch, drag radials, and REW power (big surprise). I am lucky that the PPF or other components haven't broken yet (and I have checked). I am convinced its just not a good design for what I am trying to. The grabby clutch chatters while grabbing and that vibration goes through the ppf and driveshaft into the rear end and eventually the tires. I wish they had a solution where I could solidly mount the transmission ( I think it would dampen the vibration or maybe break something )..... Anyways, I changed my trailing plugs to a 11 heat range with 10s still in the leading. Other than that the car drives and runs real smooth.
A quick pull the verify that everything is still working over the weekend. Car can blast from 25-95 mph in a few seconds. Turbo 22-25 psi. Still ungodly loud with the open gate.
I'm not sure how much one of those will help. It feels like the majority of the vibration is between the trans tail-shaft and the rear differential. I have seen some solid differential braces for the rx8, but they look real flimsy. I may try to buy some steel and making something on my own.
01-06-2019, 01:28 PM
)..... Anyways, I changed my trailing plugs to a 11 heat range with 10s still in the leading. Other than that the car drives and runs real smooth.