DeltaT

iTrader: (5)

I got a lot of good advice from you guys here, and while I'm not completely done with the changes I have planned (stiffer brackets, shorter & more direct belt setup), I beefed up this current setup enough to finally wring 10.5# of boost with very little slip out of my new Vortech V-2 SQ T-trim.

Here's my newest datalog:



I have the 4L80E set to shift at 6250rpm right now - the vertical line shows my peak MAP of 172.54.

I added another HD Idler before the blower to increase pulley wrap and shorten the unsupported length coming up from the crank pulley.

I also added a stiffening 'outrigger' to my tensioner, to support the tensioner pulley that was sitting out on a post that would flex under heavy load.

All this let me really crank up the tension on the 8-rib.

So today I finally got everything in place and tight, and went out tuning.

Here's the datalog I posted about 10 days ago, and you can see the boost only hit 8.5# for an instant, then start to slip down to about my normal 7. After a run like that there would be rubber dust all over the mount plate:



Now, after about 45 miles of driving and a bunch of WOT pulls, there was only a little puff of dust near the pulley.

This is on a SBC 383 I built, 4-bolt GMPP block with short fill of Hard Blok, solid roller (230/236, net lift .601/.603", 112LSA), 9.6:1, big FMIC, 72# injectors, Holley 950 Pro wideband & single plane, 7" crank pulley, 2.95" blower pulley (hi traction), 4L80E. This is in my sleeper 4DR 81 Malibu Sedan. With the S-trim maxing at 7.2#, it put down 501rwhp/470rwt.

The 6250 shift point puts my blower max rpm at 53,585rpm out of a rated max 55,000rpm. I still have a 2.85" hi traction pulley in reserve, and two stages of nitrous installed but not yet hooked up.

Does this seem like a reasonable boost amount for this setup?

I will post pictures of the new mods and setup tomorrow.

Thanks to everyone that weighed on my 'Vortech T-trim upgrade from S-trim' thread. I really appreciate the help!

Jim

My Site: http://home.mindspring.com/~jim_fisk/id1.html

stevieturbo

Good result...and the log is interesting.

Why are the TPS and RPM not in sync ??? My own ecu tends to do this when logging at times.

Boost/rpm drops, before my foot comes off the throttle ( according to the log ) yet I know this isnt the case.

Although I see boost is still struggling a little above the white line marker circa 5600rpm ???

engineermike

My old T-trim 383 / AFR 210 / 224/236 cam made peak power up at 62 - 6500, so I'm thinking your solid roller 230 should spin a little higher.

I still believe the T-trim does best closer to 13 - 15 psi, but I really had belt slippage problems when I tried to go over 13.

Mike

DeltaT

iTrader: (5)

Thanks for the feedback.

Mike, I'll next set my shift point to 6400 and see what happens. I'm hoping the boost line continues to go up a bit. From your comment, it looks like your 383/T-trim was in the 13# range at peak? Any numbers from that setup? How was she in the midrange?
Is the LT4 in your sig a totally different motor?

Stevie, what happened here is that I made a WOT run in 2nd, then let off as soon as it stabilized in 3rd. I wanted to see if the shift caused any belt slippage. Unlike you I don't have to lift my foot to shift! I do notice that my ECU reports an rpm spike during the shift. I don't believe it is a real rpm spike because the motor note does not change. Since my tranny is programmable, I can tighten up the shift times and see what happens to that reported spike. When you say "I see boost is still struggling a little above the white line marker circa 5600rpm ???", you mean that little blip/dip on the upper datalog?

I looked at the mounting plate this morning and there is a bit more dust than I had thought. I still have some major upgrades to get to, but I'm a lot happier than last week!

Thanks,

Jim

engineermike

Yes, it was around 13 psi peak. I tried going higher using a smaller Reichard blower pulley and only got about .5 psi. I removed the inlet tract and got 15, but couldn't drive it like that.

With the T-trim, aftercooler, LT4 intake, AFR210 heads, 224/236 cam, 383 cid, 8.5/1,. . . full weight, with a TH350, Vigilante 2800, and 3.42 rear gear, I ran 10.40 at 133 mph. I dyno'd 550 rwhp. The mid-range and response of this combo was awesome. I pulled a 1.53 60' time off the foot-brake with the tight converter, relatively tall gear, and 27" tires.

The engine I have now is basically the same. It's now 388 cid with slightly lower compression. I tightened up the converter, switched to a 3.00 gear, and a single turbo. I've since run 9.9 at 146 mph and dyno'd 695 rwhp at 17 psi. Part of the reason I switched to turbo was because I was tired of piddling with pulleys and belts trying to get 15+ psi from the blower. Though, I do miss the response of the T-trim. I don't care what people say about fast spooling turbo's - they'll never hit like a blower.

As an experiment, I turned the boost down to 13 psi to see how the turbo compared to the T-trim, and it made about 570 rwhp.

Mike

DeltaT

iTrader: (5)

Mike, at those boost levels is the aftercooler a restriction? They look sort of small. Are you still using it? Those are some nice numbers on both setups, especially for an 8.5:1 motor on a centri.

What's your compression now? What are you using for an engine management system?

Have you sold all your extra T-trim bits, like the Reichard pulley?

Thanks,

Jim

engineermike

I made 550 rwhp and pulled 133 in the quarter with it. I later used it for a while after I swapped to the turbo. I actually made 685 rwhp through it at about 22 psi boost. That would have been good for about 145 in the quarter through the aftercooler. Not too bad, but the pressure drop through it was getting excessive. I don't remember the exact numbers, but it seems like the drop was over 2 psi. I since had a Bell unit custom built (nice quality BTW) and pressure drop is <1 psi now.

My compression is around 8.4/1. For EMS, I'm using the stock computer with MAF using PE to enrich. If Moates gets the real-time LT1 tuning working, I'm going to do a 3 bar SD tune.

Nah, sold it all to go turbo.

DeltaT

iTrader: (5)

Yes, I have a Bell now and they did a nice job for a much better price than Spearco.

What's your underhood heat like now with the turbo? Anything about going turbo you regret?

Thanks for the info.

Jim

engineermike

I didn't notice a big difference in underhood heat, though I'm sure it's there. I only wrapped the downpipe because it ran close to some wiring. I also built a heat sheild for the turbine housing.

My complaint about the turbo is the lag. It does make more power, is quieter, and the car actually runs cooler (less load on the engine at idle and cruise). However, I miss the instant hit of the 383/T-trim combo.

Mike

DeltaT

iTrader: (5)

Mike, where do you have your IAT sensor located? What temps do you usually get during a run?

Thanks,

Jim

engineermike

It's in the normal location. With the Methanol on it, the boost temps at 17 psi run about 10 deg below ambient. I don't think my answer helps you much, though. . .

Mike

DeltaT

iTrader: (5)

No, cuz my setup is anything but normal... I'm thinking of moving it out of the single plane, because I believe it shows high due to the heat soaked metal. Minor issue for now.

I am adding the FJO Racing methanol injection over the next few weeks - getting the hole in my hat enlarged for the 1/2" NPT injector solenoid. It's a cool unit that interfaces directly with my FJO Wideband unit to provide closed-loop methanol enrichment to target AFR's via a 3D MAP/TPS or MAP/RPM setup like a fuel map. This will be my protection instead of the 100 octane I am using to tune right now.

I'm thinking of starting with a 66% meth, 34% distilled water mix to keep the boiling point of the mixture higher than pure meth. With the meth, the big FMIC and the J&S Safeguard Knock Controller I already have installed, I should be pretty well insured, unless I do something crazy.

I'm really hoping to hit >650rwhp on pump gas with meth, at any time & temperature of day.

Jim