Twin turbo 93 LS Notch
08-30-2017, 07:41 PM
#301
Went 8.0 @ 103 in 1/8th.
I think i could run the same times on one of these turbos easy and it would spool super quick. The car has no intercooler. Filters are large, but i do have the pre filter over them. might try removing that. I picked up a magnavolt fuel pump booster and plan to up the alky inj and drop ethanol % to e50 or so. Id like to see 15lbs. Also going to shim these .660 lift springs. Only have a .525 lift cam.
Voltage booster installed...
I think i could run the same times on one of these turbos easy and it would spool super quick. The car has no intercooler. Filters are large, but i do have the pre filter over them. might try removing that. I picked up a magnavolt fuel pump booster and plan to up the alky inj and drop ethanol % to e50 or so. Id like to see 15lbs. Also going to shim these .660 lift springs. Only have a .525 lift cam.
Voltage booster installed...
Last edited by Forcefed86; 09-14-2017 at 08:08 AM.
08-31-2017, 07:47 AM
#304
I’m not against nitrous but I don’t think I’ll need it. Now that I have the 2-step going it was making 6-7lbs pretty quick. Think it will be a whole new car leaving in boost.
Timing’s at a commanded 20* on 10lbs. But pulls out about pulls 5* due to charge temps by the end of the 1/4. Peaked about 210*. Still real new to tuning a non-intercooled setup. At sub 9:1 compression and only 10lbs… I think I could throw another 5* of timing at it, but I’ll max out the boost before playing with timing. Was on the rich side with E60 as well.
If it would pull to 7k I think this setup would be awesome. Need to look into that next.
Timing’s at a commanded 20* on 10lbs. But pulls out about pulls 5* due to charge temps by the end of the 1/4. Peaked about 210*. Still real new to tuning a non-intercooled setup. At sub 9:1 compression and only 10lbs… I think I could throw another 5* of timing at it, but I’ll max out the boost before playing with timing. Was on the rich side with E60 as well.
If it would pull to 7k I think this setup would be awesome. Need to look into that next.
08-31-2017, 09:21 AM
#306
Nope… had it setup as a switched 12v instead of a switched ground. And the car has no brakes on the rear so I can’t “brake boost” it. On the trans brake alone (without the 2-step) it makes about 2-3lbs. But as soon as I release it, it falls on its face completely to zero boost.
08-31-2017, 12:04 PM
#307
Nope… had it setup as a switched 12v instead of a switched ground. And the car has no brakes on the rear so I can’t “brake boost” it. On the trans brake alone (without the 2-step) it makes about 2-3lbs. But as soon as I release it, it falls on its face completely to zero boost.
09-09-2017, 08:27 PM
#308
The china $13 MAC valve finally came. Wired that in and have some boost control. Drilled a tiny hole so the top port can vent. Plumbed it this way.
Working on the boost by speed, but my wheel speed sensor is junk. Had to order another.
Should run alot better next track visit.
Also threw the exhaust cutout on. They are normally open and vacuum closes them. Also have them on a vacuum switch so I can control them.
It's crazy how quiet it is. I don't even have an exhaust system on it. Just close the dumps all the way and when I want it quiet. Just enough exhaust escapes to keep it running. I tapped the exhaust down pipe as well. Will measure the back pressure. Not really concerned with it unless it's out of control. I'll never try to run it hard with them closed. Might set it up to be slightly cracked when closed. But right now I love how quiet it is. I can sneak out of the garage without waking the baby.
Working on the boost by speed, but my wheel speed sensor is junk. Had to order another.
Should run alot better next track visit.
Also threw the exhaust cutout on. They are normally open and vacuum closes them. Also have them on a vacuum switch so I can control them.
It's crazy how quiet it is. I don't even have an exhaust system on it. Just close the dumps all the way and when I want it quiet. Just enough exhaust escapes to keep it running. I tapped the exhaust down pipe as well. Will measure the back pressure. Not really concerned with it unless it's out of control. I'll never try to run it hard with them closed. Might set it up to be slightly cracked when closed. But right now I love how quiet it is. I can sneak out of the garage without waking the baby.
Last edited by Forcefed86; 09-09-2017 at 11:25 PM.
09-10-2017, 12:05 PM
#311
Jb welded one if those super strong neo magnets in a nut fixed to rim. Where weights would be. Guess the wheel flexes more than i thought. Had about a .010 gap. Managed to contact and damage speed sensor. Going around a corner. (slowly)
Closer to hub would be better, but not much space.
Closer to hub would be better, but not much space.
Last edited by Forcefed86; 09-11-2017 at 08:29 AM.
09-13-2017, 03:09 PM
#313
Staging Lane
I'm stoked you got the cutout to work like that. That's way more effective that I would have imagined.
What vacuum do you notice them shutting at?
Do they open quickly when you hit the throttle?
Does it flutter around much?
I'm guessing it's still loud for second or two every startup?
I built a very similar system with dual vacuum-shut valves on each downpipe but have yet to start the car.
I plan on running a 0-5V trim pot to my MS3 and PWM'ing the solenoid to have a "loud dial". Hope it works as well as your setup.
What vacuum do you notice them shutting at?
Do they open quickly when you hit the throttle?
Does it flutter around much?
I'm guessing it's still loud for second or two every startup?
I built a very similar system with dual vacuum-shut valves on each downpipe but have yet to start the car.
I plan on running a 0-5V trim pot to my MS3 and PWM'ing the solenoid to have a "loud dial". Hope it works as well as your setup.
Last edited by shainiac; 09-13-2017 at 03:17 PM.
09-14-2017, 07:42 AM
#314
Track is pretty random. Owner is a racer so he’s been out the past weekends and this weekend too. I hate going to events because I never get many runs but I’ll try the sept. 30 street fights event. Otherwise the next TNT is Oct 28th…
09-14-2017, 07:54 AM
#315
TECH Resident
Wow, most of our tracks have a TNT class weekly. You run with each round of the class racing. So as many as 8-10 passes. On a TNT only day, you could round robin and do 20-30 passes. Guess we take for granted how good we have it. Of course we do get booted on the first pass without all the safety equipment. I see you guys making passes regularly like that. I'm jealous...
09-14-2017, 08:07 AM
#316
I'm stoked you got the cutout to work like that. That's way more effective that I would have imagined.
What vacuum do you notice them shutting at?
Do they open quickly when you hit the throttle?
Does it flutter around much?
I'm guessing it's still loud for second or two every startup?
I built a very similar system with dual vacuum-shut valves on each downpipe but have yet to start the car.
I plan on running a 0-5V trim pot to my MS3 and PWM'ing the solenoid to have a "loud dial". Hope it works as well as your setup.
What vacuum do you notice them shutting at?
Do they open quickly when you hit the throttle?
Does it flutter around much?
I'm guessing it's still loud for second or two every startup?
I built a very similar system with dual vacuum-shut valves on each downpipe but have yet to start the car.
I plan on running a 0-5V trim pot to my MS3 and PWM'ing the solenoid to have a "loud dial". Hope it works as well as your setup.
It is OEM quiet with full vacuum though. I mainly use it to get the car in and out of the garage without waking up my kiddo or the rest of the neighborhood. Or if I cruise up next to my police pals. I should adjust the valve so it doesn’t close fully. This still quiets it down a lot, but not enough to sneak in and out of the garage.
I don’t have a vac/boost gauge at the moment so I’m not sure. It pretty much instantly opens/closes near as I can tell. No flutter. Less than a second for sure to close on startup. Doesn’t take much vac. I did try the valves that open in boost first. It was so restrictive that it wouldn’t build enough boost to open the valve. I have these FS if anyone wants them, PM me.
Also found I could easily control them with a tiny ($3) 12v vac pump. Problem was I’d need to rig up a solenoid inline to vent the vacuum when you turn the pump off. (or have a stronger pump) I tried a super tiny (like .010) bleed hole but the baby pump couldn’t keep up. Haven’t been able to find a better small vac pump. Seems like this would be the way to go. That way I could close it fully before startup. Could PWM the pump as well.
Last edited by Forcefed86; 09-14-2017 at 08:27 AM.
10-30-2017, 09:54 AM
#317
Been driving this thing all over. Can’t say enough about the street manors with the 2.73’s. Acts just like a glide with overdrive. It’s a beast from a 60mph highway roll in 2nd.
Made another track visit and just couldn’t get the launch right. Could make 6-7lbs on the brake but it fell on its face at the TB release. Went 10.9x @ 134 on 13-14lbs. Track wasn’t happy with me for not having a cage. I decided my goals were met and to leave the car alone at his point.
Then shortly after the last track visit I noticed white smoke coming out of the pass side downpipe on hot starts. Others have been having the same problem with these turbos so I assumed that was the problem.
I went ahead and ordered these new 64mm billet GT35’s to try. Went with the .63 T3 hotside. They should spool crazy fast compared to the 72s. They are so small by comparison I’ll need to redo the drains and down pipes to make them work. Won a bid for $250 each shipped.
When I pulled the 72/68’s they were bone dry. I saw no trace of oil leakage. Plugs looked “ok” but had a lot of miles on them so it’s hard to tell. Did a quick compression test thinking I could have crunched a ring land and it came back good. Waiting on a borescope to peek at the piston tops. I can’t imagine I crunched a piston on 13-14lbs but I’ve never really played with a hot air setup. Also was running E60ish for fuel content. So who knows.
Fancy looking GT35’s.
Size comparison between the 72mm and the Gt35. The exhaust housing difference is crazy.
Attachment 712962
Made another track visit and just couldn’t get the launch right. Could make 6-7lbs on the brake but it fell on its face at the TB release. Went 10.9x @ 134 on 13-14lbs. Track wasn’t happy with me for not having a cage. I decided my goals were met and to leave the car alone at his point.
Then shortly after the last track visit I noticed white smoke coming out of the pass side downpipe on hot starts. Others have been having the same problem with these turbos so I assumed that was the problem.
I went ahead and ordered these new 64mm billet GT35’s to try. Went with the .63 T3 hotside. They should spool crazy fast compared to the 72s. They are so small by comparison I’ll need to redo the drains and down pipes to make them work. Won a bid for $250 each shipped.
When I pulled the 72/68’s they were bone dry. I saw no trace of oil leakage. Plugs looked “ok” but had a lot of miles on them so it’s hard to tell. Did a quick compression test thinking I could have crunched a ring land and it came back good. Waiting on a borescope to peek at the piston tops. I can’t imagine I crunched a piston on 13-14lbs but I’ve never really played with a hot air setup. Also was running E60ish for fuel content. So who knows.
Fancy looking GT35’s.
Size comparison between the 72mm and the Gt35. The exhaust housing difference is crazy.
Attachment 712962
10-30-2017, 10:18 AM
#318
You think the turbos are just stalling out when you let go of the brake, or the load of the 2.73s? Is timing pulled back to make boost on the two step? Mine would fall over too if I had the timing pulled back on the two step. Finally tuned around it.
10-30-2017, 10:42 AM
#319
Not sure. My starting line ratio with the 27” tire, 2.73 gear, and 2.48 1st gear of the TH400 is 6.77. MUCH better than my Rx-7 (5.72) It’s actually better than the typical a 3.73 gear glide setup with a 28” tire (6.56).
I tried the advance timing route on the brake with this setup, seemed to get into boost faster. I’m at 34* on the brake and pull back to 24* or so by 5lbs. I believe I was at 21* by 7ish. At 15lbs I’m down to 15* at pk tq and back up to 19 by 7k. I’m also pulling timing based on intake temps. Averages out to around 14*-15* most of the run at 13lbs. So not very aggressive for lowish boost IMO.
The baby turbos should more than take care of this issue. I’m assuming I’ll have the opposite problem then!
Already wishing I went with the .84 T3 housing option after seeing these. (which is supposedly what those 72/68 T3’s are 
) Good news is it’s an inexpensive upgrade if these are too small.
I tried the advance timing route on the brake with this setup, seemed to get into boost faster. I’m at 34* on the brake and pull back to 24* or so by 5lbs. I believe I was at 21* by 7ish. At 15lbs I’m down to 15* at pk tq and back up to 19 by 7k. I’m also pulling timing based on intake temps. Averages out to around 14*-15* most of the run at 13lbs. So not very aggressive for lowish boost IMO.
The baby turbos should more than take care of this issue. I’m assuming I’ll have the opposite problem then!
Already wishing I went with the .84 T3 housing option after seeing these. (which is supposedly what those 72/68 T3’s are ) Good news is it’s an inexpensive upgrade if these are too small. 