What upgrade to do next? Suggestions???

[Jersey]

Ok, so i'm still working on my cousins '77 turbo build. SOMEDAY i'll get back under my hood! We ran my '73ZT against his '77 tonight and we're dead even. I mean DEAD EVEN. Go figure We did about 8 runs starting in 3rd to the top of 4th and the Z's were side by side each time. I really don't think he's getting the full potential out of his T3/T4 because he should be pulling on my T3 so i'm trying to figure out what should be his next upgrade and just looking for some suggestions. Here's what he's running...

 

'77 280

T5

3.54/CV's

NPR IC (medium)

custom 2.5" DP

3" mandrel exhaust

60mm TB

P90A just completely redone

1 new cast piston

1mm metal HG

Greddy BOV

T3/T4 - 50trimE in a B housing, .63 Stage III clipped, oil/water cooled, ported WG hole

MSD fuel pump

3/8" feed and return fuel lines

370cc injectors

custom fuel rail

electric fan

ACT clutch/PP

stock '83 ECM

stock FPR

stock '83 ignition (22deg BTDC)

grainger type boost controller

running around 17-18psi on the edge of ping

 

Now i'm thinking the most logical direction to go at this point is with an aftermarket ECM but $700-$1000 is hard to drop right now so...

 

The little homemade grainger BC seems to be doing ok but spikes to about 20-21psi before it comes back down and level off at around 18psi. Not liking that too much and i think we're exceeding the little $10 item We pulled the plugs after some high boost runs and the plugs seem just a little white, which i would think running a bit lean on top. We also had to close the gap a little (38) because i think the hybrid was blowing the spark out at higher boost levels. So i'm thinking he needs to do one of three things at this point without dropping a nut on a Haltech

 

Adjustable FPR or

MSD 6A BTM or

a REAL boost controller

 

I'm just trying to figure out which way he should spend a little money first to wake his 77 up a bit. I know his '77 is a bit heavier than my '73 (and i am a beetter driver ) but i think that 50trim should more than make up for the weight difference... and i hate to be side by side with him with my little T3 pushing 18psi If i'm missing something that i should be considering upgrading, please post it. Thanks in advance.

[fl327]

With almost the exact driveline minus the upgraded turbo and high boost levels and the same efi setup, its gotta be the weight... 400lbs or so sounds like its evening things up in your favor. Have him drop that setup into a 70 and gut the interior and heater core, then throw your setup into a 510

[rags]

Gotta be the weight. Are both cars running the same wheel tire combo?

 

Joe

[Jersey]

Thanks guys. I'm figuring the weight has got to be a big factor also but i still think his Z should outrun mine, if even just by a little. I'm not so good at reading compressor maps so i'm not sure at what boost level his T3/T4 will run out of breath but i'm thinking he still could get a few more psi out of it. Once we get a little more fuel on top by adjustable FPR and/or upgrade his ignition with something like a MSD BTM and can dial back total advance timing, then i think we can bump his boost up a little more and then he should be good. It's never enough i guess

 

327, I'm going to make his Z a bit faster than mine then he's on his own Then i can get back to my Z and then show him why it's good to be light

 

Joe, i'm running 215/50/15's and Nicks got crappy 205/60/15's. Were both getting ready to order some 16's or 17's with 225/45 or 50's. Then we both need drag radials and get to the darn track! moneymoneymoney! You need to come and show us what a fast Z is like

[rags]

How about a nice turbo cam that won't be out of breath at 5 grand? I would think we would get a nice break if we bought 3 of em.

Joe

[Guest bastaad525]

adjustable FPR would be the cheapest upgrade and if you're pretty sure he's running a bit lean it would definatley help recover some of his lost power. The MSD obviously wont make him any faster.... if anything the BTM module is might kill off some of his power... retarding timing in a turbo motor makes a big difference. A real boost controller, a fancy one with a programmable boost curve, might help you take advantage of the ZXT ECU's default fuel curve, which always seems to run way rich up to about 4000-5000rpm, and then lean out after that. I've always wondered if I could program a boost curve that would hit high at low RPM, use up all that extra fuel and get the car moving, and then slowly drop as fuel leaned out for safety. In a way, I was basically planning on using the boost to achieve a nice flat 12:1 fuel ratio all the way across the rpm range. *shrug* just an idea I had.

 

 

Oh and Jersey... get rid of that ACT clutch... keep the pressure plate, but lose the clutch. It is my mission in life now to preach this to anyone who does not absolutely NEED metallic puck clutches (90% of the people running them dont need them) now that I have seen first hand what a measely 20k miles of using one of these clutches does to your driveline. A flywheel so worn and chewed up that the clutch was brushing up agains the the flywheel bolts. Busted U-joints and a worn diff from all the shock of hard shifts. A shattered pilot bearing and extremely worn thrust bearing on the crankshaft letting the crank walk 1mm back and forth. And in general, a car that was a pain to deal with on anythign but long open stretches of highway. Not sure which alternative would work for him, still be able to hold the power w/o destroying stuff... but again, if he doesnt absolutely NEED something that grippy, get rid of it, his driveline will thank you.

[Jersey]

Hmmmm Joe, so... whach ya got in mind???

 

525 - I was thinking the the BTM because of two reasons...

 

1 - he's blowing the spark out as it is and we needed to close the gap down to prevent this and

 

2 - he'll be able to bump the boost up a little more if timing was retarded by maybe 1deg per psi.

 

I think the ADJ. FPR will be my first suggestion to him to cover the leaning on top issue. The fancy boost controller might be a little out of the price range right now and if he were to spend that kind of $, i think i'd have him save for aftermarket ECM and cover all basis.

 

Both he and i are running the ACT clutch, not the puck type. Grabs like a mother%#@*Q$(% Sorry to hear about what happened. Hope you get it all fixed up. Thanks for your suggestions.

[Forrest]

Jersey, when I get my MSS running correctly, I can recommend you put that in. 140$ in parts, total control over fuel and spark. Unfortunately I'm still having problems, so Moby will have to be your inspiration. If you wait a week or so I'll have it licked and if you run into my probelms I can help with those too.

 

Baastad - MSD has improved people's track times over stock ignition. So that's not true. If the BTM unit allows you to run more boost with retarded timing, you can get more power using that, as well. Obviously you wouldn't be setting it to retard timing if you're not close to detonation already.

 

And my flywheel is just fine. Did you drop your clutch a lot? A friend of mine shredded one of those ACT street discs in under a week.

 

I personally don't know what all the fuss is about with the copper discs. I have not had any problem slipping it into gear. I drive around in heavy traffic - it's not a big deal. I was very surprised when I got installed, I expected it to be horrible. You just have to be gentle. I like it.

[Scottie-GNZ]

The MSD obviously wont make him any faster.... if anything the BTM module is might kill off some of his power... retarding timing in a turbo motor makes a big difference.

False statement! Unlike an NA, retarding timing in a turbo motor as boost is increased makes a big difference in making more power and that is what the 6A BTM will help you do. No point in getting a fancy boost controller if you cannot turn up the boost because the timing is too high. The less timing you run (advance that is, not inital) the more boost you can run, the more power you make.

 

I think you guys are skating on thin ice running 18+psi boost on pump gas with the stock ECU and some fuel system parts. If the 77 is 400lbs heavier, that makes all the difference in the world, plus, if the engine is pinging, it is losing power.

 

You guys should buy an LM-1 and share it. That is the first thing I would do.

[Guest bastaad525]

okay I stand corrected... WAAAAAAAAY corrected Or do I? I remember Yo2001 posting about some dyno tuning he did, where he was playing with boost and timing and such, and ended up getting a big spike in power, something like 20ftlbs of torque over where he started, by advancing the timing 2-3 degrees and changing nothing else. I haven't played with timing on the dyno with my own car so haven't really got more info than that... but I've kinda kept that post stuck in my head and after that decided that bringing the boost down a bit while upping timing was probably the better way to go and it did feel better to the butt dyno when I did. From that post I got one impression lodged in my brain: timing in a turbo motor makes a LOT of difference, and RETARDING the timing probably costs you quite a bit of power, in the same way he gained quite a bit from such a small advance. I dont know enough to say for sure which nets more increase or loss, timing or boost, but in Yo's case it definately seemed to be timing. I remember this 'safety rule' as well: decrease the timing 2 degrees for every 1psi of boost increase. Now if my car behaves like Yo's, I would lose 20ft lbs for those 2 degrees of retarded timing, and I KNOW I wouldn't gain 20ft lbs back from 1psi of boost increase, probably more like 5 or maybe 10ftlbs at best. So how much more boost could I REALLY run for those 2 degrees of retard? Now, if Jersey's cousin sets his BTM to retard 1 degree for every psi of boost, that's gonna be 18 degrees retard... by Yo's numbers that sounds like it would lose a LOT of power, of course it wont be 10ftlbs per degree as it was in Yo's case, I'm sure it tapers off... but how much power WILL he lose? How much more boost WILL he be able to run? How much of the lost power is that going to make up for or will he gain more power than he lost by retarding the timing? Not trying to argue, I just want to know how this all works and why.

 

 

EDIT: decided to look up his old post... well I guess it really doesn't make a good argument for NOT retarding timing to increase boost... but it certainly sounds like he did get more results from the timing alone. Here's the thread:

 

http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=25402&highlight=dyno

 

We gave the car 2-3 deg timing and turn the boost a turn (now it holds solid 12psi, after spiking 14psi ) We also turn the fuel pressure up to 44psi. The timing helped alot, it alone gave me 20ft/lb.

 

To be honest I was very surprised to find that timing made as much difference as it did... I'm sure there are other variables there that I dont know about.

Forrest - you're one of the first to say the MSD alone DOES make a difference in track times... many times I've asked on THIS forum... like when my first MSD 6A blew, and I was asking was it even worth it to get another one... does it make any more power, does it make the car any faster, the common consensus was no, it wasn't going to improve power at all. Same thing when I was talking to the dyno shop guy... he had seen guys do before and after on the MSD and not come away with more power from it. I thought they were more useful on turbo cars just to keep the spark from blowing out at higher RPM's under boost, preventing misfire. Personally my Z's have always seemed to run a bit better with the MSD, so I decided to get a replacement anyways. I can't say the car feels any faster, but it definatley runs smoother and starts easier. I never did dyno afterwards... I was going to right after installing it, but again, was pretty much advised not to as no one expected to see any power gains from it.

 

About the ACT, I was running a metallic six puck clutch, and I can't say, relatively if I dropped it a lot... in my N/A motor I did drop it here and there, but living where I live I dont get a lot of chance to do stuff like that. But I will say this, when we took the clutch, PP and flywheel out of my N/A motor to swap over to the turbo drivetrain, it didn't look that badly worn at all. Since then I had done a lot more slipping of the clutch as dropping it in a turbo gets you lots of bog... and when I pulled it not even 6000 miles later it definately looked a lot more worn than before. And anyways, I thought dropping it WASNT hard on the flywheel... but rather other parts of the drivetrain? I thought slipping it was what ate the clutch, flywheel, pressure plate, and the chatter that results from slipping it was the cause of thrust bearings and pilot bearings getting trashed? Certainly seems to be the case in my above example. I never ran the non-puck ACT disk, I'm only speaking about the puck type, so I take back that suggestion as well

 

 

But I will also say this, since then I have installed a stock clutch with what I was told by the barely-english-speaking salesperson was a heavy duty Daikin pressure plate... but what really feels and cost like it was a stock PP... and at 200hp/234ft lbs it holds great... I've tried to get it to slip and I can't. And the pedal is soooooo easy to push... so much nicer than dealing with my ACT which has caused me enough leg cramps to last a lifetime. Obviously engagment is silk smooth as well... I dont feel like I'm breaking stuff Maybe it's a bigger deal for me because up until recently I probably drove my Z more than most guys here, it was my daily driver, and living in L.A. of course traffic is the rule, not the exception. It just really enlightened me to the fact that sometimes going with the beefier part isn't always the best way to do it, unless you really need it. This particular issue is very new to me... I was always under the impression that I NEEDED the ACT, that the stock disk wouldn't hold this much power... but there it is... working just fine. But I know I'm kinda the low powered guy of the bunch so maybe this suggestion really doesn't apply to anyone else... I'll try to keep my personal vendetta against ACT from spilling out like that again

 

Jersey - I would definatley like more info about the disk you are running though. I keep thinking that one day I will finally increase my Z's hp over the 200 it's putting down now, and then maybe this mild clutch isn't going to hold it. If that happens, I'll definately go back with an ACT pressure plate, but not sure if I should stick with the stock disk or what. Throw me a link or something to the disk you're using? Sounds like it might be a good alternative.

[Turbo Meister]

The MSD 6AL-BTM has a rotary dial that allows 1,2,3, degrees of retard per lb of boost, for a total of 20 degrees retard. Actually, if the BTM is turned one increment further where 4 would be, if it were so marked, it will retard by 4 degrees ( MSD denies this ). So in effect, all this unit does is vary the speed with which you activate ignition retard.

With no other changes, if I retard by 4 degrees(max boost 15psi) the TT383 Chevy Z runs 113 mph in the 1/8th mile. If I retard by 3, it runs consistent 116 mph ( in the 1/8th not 1/4 mile ). Retarded ignition timing does hurt power but saves parts.

The MSD unit is powerfull, too. After my last engine rebuild the engine started quite well but ran rough. It also seemed to be down on power so I tried different timing curves that had proven successful in the past. It still ran rough so I checked the usual culprits. To my surprise I discovered that I had neglected to hook up the #s 2,4,6,8, plug wires to the sparkplugs. The engine started but ran rough on half of the V8's cylinders.

Hanns

[rags]

Good point Scottie. Jersey, bring the car over and we'll hook up my LM-1 to see what's actually happening.

 

Joe

[Scottie-GNZ]

Hans,

 

no surprise on your results with retarding timing, BUT, you retarded the timing running the same boost.

 

Let me repeat what I said: "The less timing you run (advance that is, not inital) the more boost you can run, the more power you make. ". Now, let me restate it. Retarding timing as you increase boost allows you to run more boost safely. You make more power from adding boost than from adding timing. Hans, in your case, when you retarded the timing, you could then have run more boost.

 

 

B-25,

 

your entire argument about timing loss/gain is based on a SPIKE!. 'Nuff said.

[yo2001]

What you want to maxuim timing and max boost.

 

I think Scottie is partial right, Yes you want max boost with less timing specially on pump gas, and have enough intercooler to cool the hotter intake temp and if you have enough fuel to support the boost level. Yet if you out of injectors, IC, or turbo, then timing will help alot. My case, I was out of the stock injectors so I added timing, plus with timing too low, it runs like crap. The power band got really jaggy. Stock ECU got real safe timing setting (Z31 ECU) with more timing, it smooth the curve up. Also timing can kill engine just as fast as running high boost.

[Jersey]

First off, thanks for all the responses.

 

Forrest - I've been thinking of going MSS for both our Z's for a bit but i still see most trying it having little issues and hate to have either Z off the road right now (nice weather ) for any long period of time. It is a good possibility though. Keep me posted on your progress. Thanks.

 

Scottie - Isn't it common practice to push everything to edge, no matter if it's the lawn mower or your 500hp Z?? lol. I do understand what you mean and yes, we are exceeding any optimal performance that the stock ECU can deliver. If either of us come into a good chunk of change, we'll go aftermarket ECU. If i had the $350 for the LM-1, i think i'd save a bit more and just go completely tunable/programmable. We should be going to the dyno soon and for $100, you get an hour to pull as many times as you want and make any adjustments within the hour. That should allow us to dial in best we can for the time being. Not much to adjust but at least we'll know where we're at. Hey, I just thought of a great solution! Still have your Z? I'll buy yours and then not have to worry about any of this since you're all set up, and then some! lol. Although, i wouldn't get that sense of pride or acomplishment Thanks for the reply.

 

525 - Both Nick and i are running the ACT Clutch Modified Street Disc (NSD007S) So far, so good. Not sure of either of our HP but it seems to hook pretty good and is smooth. When i can chirp 4th at the track, that works for me I'm sure the Act modded PP helps the grip as well but i'm really not happy with the amount of throw it takes to disengage, with just about no free play. I had to change my slave to a different size just so i wouldn't have to go completey to the floor before it released and could shift. Same issue with Nicks 280. Just my thoughts on the PP/clutch issue. The MSD - the way to think of it is - it wont gain you performance, but it will allow it. Thanks.

 

Joe - i'm saving all my "rags garage" time for my Z, not Nicks Appreciate the offer. Maybe i'll look into getting an O2 that works with the LM-1 and try it out. Is that all i'll need? We can use my laptop as well if needed. Thanks. BTW - your HG came in yesterday so we'll hook up soon.

 

Yo - Thanks for chiming in. The Z31 ECU was my other option. Lately i've been thinking that this will get me to cartain point as well and hit a brick wall and need to upgrade again, but i do like the idea that it works much better than what we're running. Now you've got me thining about that again! ha. Thanks.

 

Again, thanks for all the opinions, suggestions and knowledge.

 

- Len

[Guest bastaad525]

What you want to maxuim timing and max boost.

 

I think Scottie is partial right' date=' Yes you want max boost with less timing specially on pump gas, and have enough intercooler to cool the hotter intake temp and if you have enough fuel to support the boost level. Yet if you out of injectors, IC, or turbo, then timing will help alot. My case, I was out of the stock injectors so I added timing, plus with timing too low, it runs like crap. The power band got really jaggy. Stock ECU got real safe timing setting (Z31 ECU) with more timing, it smooth the curve up. Also timing can kill engine just as fast as running high boost.[/quote']

 

 

Okay see that's info I didn't get from your old dyno thread Yo I figured I had to be missing something there. I'm very glad this discussion came out as it has cleared this up a lot for me. Again, all I took away from that thread was that little changes in timing grabbed you big changes in power, and that you could make more power advancing timing and lowering boost than the other way around.

 

I STILL want to know, if you retard timing lets say two degrees, how much more boost would this let you run? Assuming plenty of fuel and a very efficient I/C.... let's say at 13-15psi? How much power will you lose from retarding the timing, and how much potential gain from the maximum safe boost increase that the timing drop allows? By turbomeisters example (from 116 to 113mph in the 1/8th by adjusting the MSD BTM one degree) how much power is he losing there?

 

I know I definately like the way the car feels with the advanced timing... one day I'll get back down to the dyno with a wad of cash in hand.... $125 for an hour... and mess with both timing and fuel mixture.

 

 

And lastly, what would then be the optimum setup for me? I'm currently running 9psi, and 20* of initial advance. This is bone stock fuel system except for an MSD pump, and for some reason it runs just slightly higher than stock fuel pressure by itself (about 34-36psi at idle with vacuum connected, I guess stock is supposed to be 30psi?). Last time I dynoed I had it set to 10psi of boost, and about 17* initial advance. There wasnt any sign of ping, either audibly or as an erratic power curve on the dyno graph, all the way up to 5600rpm (at which point I was at about 13.2:1 A/F ratio). I've no idea how much power I have lost (or gained?) by switching to 9psi and 20*... but I would think it falls in line with what Yo was saying, about this benefitting if you're already maxed out on something (in this case, the stock fuel systems ability to supply fuel above 5000rpm). But you guys tell me, should I put it back the way it was, will I get better power that way (and, from what we saw on the dyno, it was safe, at least up to 5600rpm, which I never rev past anyways), or should I leave it the way it is?

[stagefumer11]

alright you guys are talking about the timing isuse, now im concerned if this can relate to the l20et's. i was informed t hat the factory timing was 10btc. is it sa fe to bump it up to 20btc. ? or do i endangor my motor.

 

its fairly stock apart from a intercooler, exhaust, filter. and a adjustable wastegate. im also about to get the car back from the workshop after blowing the orginal head gasket. and leaking vavles.

[fl327]

I have a feeling that on the l20et, going to 20btdc is a bad idea. sounds like that engine runs a little more compression than the l28et?

 

Nitrous jersy, nitrous.

[Guest bastaad525]

hmmm so no one gonna clarify this for me? Surely someone here has spent a lot of time on the dyno and found out the answers to these questions.....

[stagefumer11]

i tink the c ompression is 7:1:3 something like that. its a dog off boost