Question for those crossing the 1320 in 4th/5th gears

[turboglenn]

Just wondering what kinda timing you guys are running to keep det down in those gears underthe extra loads and higher temps.

This is assuming you eitherr have a stand alone with no knock sensor or aren't enabling it, or are fooling it to where the timing you program is what you get like in my ECU (but i have J&S safeguard system that i can desensitize) I ask because most tuning i've ever done and there's a LOT of tuning under my belt has been all third gear stuff (especially in DSM's becase of weak 4th's and now i know it's the 3/4 hub mainly on 2g's but tha thte 4th is tiny compared to third even inside the trans as far as gear area)

meaning are you

1.) using lower overall timing curve

2.) trimming timing by gear

3.)trimming timing by IAT's or some other engine sensor variable

4.) backing offf from what you max out on a third gear dyno session?

i know most of you guys this fast don't even dyno tune, just log passes and adjust, but ive asked bonneville people and got answers that made sense but are not feasible for a drag car... or street car, now that i've had a chance to run on a marked off 1320 and noticed i was in mid 4th crossing that line, i feel that i may be pressing the cylinder pressures a litle hard for the load.

I usually don't have issues at all even without the J&S, but i have had my ONLY issues on top speed runs where i'm in 5th making high boost on the sametiming used on 3rd gear (has been a long time since i blew one this way thgough) but i usually pop a gasket if i push too hard in 5th and have my timing for peak HP in 3rd on dyno

just wondering what ways you guys deal with the chnge from a car that goes through the traps in 3rd to one that's maxing out 4th or even getting into 5th

you mile guys can chimein too but i'm more interested in stuff that applies to morethan standing mile cars where extra weight isn't a bad thing

[bastard dsm]

dont tune in 3rd gear, if you get away with no knock in 3rd but have issues in 4th then thats the gear you sould be doing tunning pulls in. i always tune cars in 4th, i dont know why people do 3rd gear pulls when tunning. im running 28psi on 93 oct and run about 7-10deg of timming while in 4th(155mph at 8k). you can do gear trimming with timming by taking out 2-3deg but i use iat to decrease timming when air temps go up. my temps stay ambient and dont get higher than outside temps when i make a pass.im using aem v2 and evo8 knock sensor, car has made 560hp on 93oct no meth. i also start off at 5deg as soon as boost hits( full boost at 4700rpm) and work it up to 10-12deg at red line depending on the outside temps...since its hot 7-10deg is max. here is a older dyno before i fixed an ignition issue,93oct

[turboglenn]

Long time no see, glad you're back, I usually pull a few degrees over the third gear tune but there's 2 reasons i tune in third. I have no business going near redline in 4th on the street forone and on the dyno i've seen DSM's shred fourth gear easier than third and when i'm tuning for other people i don't want to breajk their stuff even when they tell me topush the limits, so i tune third and re-tune.

I use haltech and with my new IC i get down to ambient at mid third then rise maybe 4-5* too and i pull tming 2* at 120* and 1* at 112, but i rarely see over 108* F on the new FMIC. my coolant temps i use the same way, by third i'm at about 195 from the 179-185 i start at, then i'm in the 200 zone at mid fourth and past 205 usually by 2/3rds of fouth and pull a degree at 200, then another 2 at 212*

I havne't failed a HG since maing some mods and de-tununing but i just see some people are only running 5-8* timing up top and i'm begining to see why as i daily drive a car that easily makes 500HP (broke trans at 522, pull before that was 507 and the safe street tune i run is about 482hp @27-28psi, and i only run about 24-25 since breaking the trans


I use a J&S safegaurd individual cylinder monitoring system with a saturn sensor that's better suited for the engine buid than the OEM one is according to Jon of J&S, but i want to get a bosch flat type and try that out because the J&S is famouse for picking up slap on shifts or when gunning from a cruise, but it gives it back fast though

[dexterholland04]

I usually cross the traps at 7300ish and I am targeting 16-17 degrees of timing advance on Q16. I usually end up loosing a degree 210-212 degrees at the end of 4th gear. My air intake temps are in the 110-112 degree range at the top of 4th gear. The car used to pull a little more timing up top because of coolant temps, but a better radiator (I had a half-radiator in the car before) and water wetter definitely helped. I bought a Mishimoto 160 degree thermostat and I'm thinking that should really help keep temps down too. I don't ever get any measurable knock (.4-.7 degrees up top). Long answer short, I don't pull back timing necessarily...my car just needs to run a smidge cooler and I think I'll hit my target timing. Hope that was along the lines of the type of answer you were looking for!

[bastard dsm]

yea its been a long time man, good to be back on the forums.what a/r exhaust housing are you using? you might need to pull timming up top instead of dropping it across the board, you can make it peak then drop when you get closer to redline.

[turboglenn]

I'm using a t-netics T3 mani with a garrett T31 5 bolt outlet .63 a/r housing that i machined to hold a holset that i custom built, it's sort of an hx40/35 hybrid (35 turbine and 40 style 58mm 8 blade comp wheel and housing, the bolt on housings wouldn't work on my manifold without hittin the block so i machined this one because of that and lack of funds, Hell it's been so long, that last i spoke with you, you were making over 400hp on an 18g, and i was still 57 trim, i've had a PTE6776RS since then, ball bearing 5031 for 6k miles nad now my custom holset.... made 522 and broke the trans a month ago (oh and i AWD converted since you wer eon last)

but i'm haltech stand alone so my timing is what i program unless i let the J&S work it's magic, but I run timing curves that scare most DSMlink users or people who modify stock maps

my timing USE to be 16 minimum on boost above 17psi and work up to 19 or 20 by redline, but now moving more air with the larger holset nd even back on the short lived 67mm (too laggy) i've been redialing it all in, the holset is confusing because it spools like a big 16g or maybe an 18g at most, but makes airflow for over 522 because i was only at 31psi and 17* timing when i made htat pull and broke

also on ethoanol which i've got tons of studies and SAE papers on, i'm runing that on 1600 injectors and i find i need to dip timing at torque because of the massive amounts of air the holset flows so early, then i cna advance to keepup with the burn, Ionly see any knock segnal at the 5-6k range with it starting to feed back by 6k when it does knock, my curve now is 14* up till 5k at 28psi (12 at 30psi) and i slowly advaance a degree or two per 1k RPM without issue

[bastard dsm]

man you have been buisy, well your timming and choice of a/r is what might be giving your issues in the higher gears. your back pressure might be higher than your boost and at higher rpms and could cause knock. im running a .83a/r on my 6262 cea bb and full boost is around 4700rpm, if you can log another map sensor tap into your exhaust housing and run a steel tube to a small collector with a map sensor to log back pressure.

[bastarddsm]

I've always tuned in 3rd gear. Who wants to make 80-150mph pulls? My timing map is set for max power at every boost level. I've never seen a reason to pull it back for 4th gear. Even on pump 93 with a garbage intercooler. I tuned for max power in 3rd gear with no knock.

Right now on E85 with 30psi on my HY35 in up around my timing curve starts at about 15* at 4500, and ramps a degree or two per 500rpm to 7000. ending at 25*. That was max power on this setup. I think it would make more at 7k+ if my maps went that far and I could add more up there.

130mph traps in a 3400lb car on a 54mm turbo is running pretty good, especially with a clutch that slips on the big end.

Oh I run a cheap fp paper gasket and standard ARP's. My block is cracked in a headbolt hole too lol!

[turboglenn]

Just to be clear i haven't had issues like this in a long time except when i stretched the ARP 2k's and had to upgrade to L19's..

it was just thoughts i wanted to pick brains on...

My timing now is good, as long as i don't set the J&S off shifting or from anythign loose then in fourth i see a degree or two on the shift taken then it's back by the time i'm ready to llet off, don't wanna to too fast...this setup is better than most i've ran but i would like another 3 bar to log back pressure, but being disabled and fighting SS i have no money for now untill i get my back pay and monthly checks

but back on my 57 trim thre were 2 times i did 150mph pullsa and let the HG loose in the process

[bastard dsm]

im running composit felpro 35 dollor hg with arp's that have been used 3times and have had one hg fail because of knock.i make consistant 4th gear pulls as run up to 9k in some cases 160+mph and havnt had issues. if your worried about higher gear pulls lower the timming and look into a bigger a/r hot side for your turbo. i used to run lots of boost and timming on e85 till i had hg issues and backed it down just a tad and it has been golden.since then i have been looking for other ways to make power and have been more conservitive on the tune.

[turboglenn]

Originally Posted by bastard dsm

im running composit felpro 35 dollor hg with arp's that have been used 3times and have had one hg fail because of knock.i make consistant 4th gear pulls as run up to 9k in some cases 160+mph and havnt had issues. if your worried about higher gear pulls lower the timming and look into a bigger a/r hot side for your turbo. i used to run lots of boost and timming on e85 till i had hg issues and backed it down just a tad and it has been golden.since then i have been looking for other ways to make power and have been more conservitive on the tune.

You're right, and that's what i've done, the SAE papers i have say that leaner E85 AFr's require moretiming to get them lit and burning at the start and that's why people can get away with 12.5:1 and 19* timing.. richer mixtures light off faster and get burning right away and since ethanol actually burns faster but colder than gasoline it needs much less timing when rich or you will knock (those who say e85 won't or can't knock just havne't paid attention ort pushed it right i guess)

Anyway, I found this turbo comebo and engine combo with AWD combined higher loads likes to be in the 11.5:1 area and likes it's timing about 16-17* peaked out, anymore my KS picks up like .5 on the shift from slap and now doesnt' show anything until i've made repeasted pulls in HOT weather and the engine temps are up and combustion chamber temps are high.. even in 4th/5th i've ben doing well lately

if anyone wants to see that SAE paper, let me know and i'll email it to you or something but i don't know about the rights to post it publicallyu without permisssions since i've never seen anyone else do more than provide links tothem