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New DR750 owner-- guess the dyno!

85K views 536 replies 80 participants last post by  kywhitelightning 
#1 · (Edited)
Okay guys the day is almost here! For those of you who may not know- I bought a 1992 VR4 in Vegas and I am now only a day and a half from being able to FINALLY drive it. I have been waiting patiently for my baby and in the process of waiting I have spoiled her with goodies.

I will only have my car for a good week before turning it into the masterminds that are FSR Motorsports and allow them to create my dream vehicle. With that in mind, and running off of Benson's dyno post, I am wondering what you guys think the final WHP will be.

P.S. there will be a prize for the person who is closest to the end WHP.

The mods:

3.1l engine
DR750 turbos w/ wastegate actuators
3S Pro EFI 128 ECU (tuned by the amazing trio at FSR Motorsports)
IBoost Controller w/ boost control solenoids
E85 with flex fuel
Walbro 400lph
FIC 1100cc High Z injectors
HKS DLI
NGK spark plugs/wires
Southbend Stage 3 clutch
Intake
3 in DP/exhaust
HKS BOV
92.5MM Weisco pistons
Brian Crower H Beam Rods
Forged Crank

What do you guys think?

Enjoy.
 
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#138 ·
The car is currently in the final stages of tuning so there will be more numbers very soon! This is currently the dyno of the car on my low boost setting (proefi is designed to give me 5 different settings with the turn of the knob)with e85. Looking forward to seeing them turn it up!

 
#142 ·
Yeah, that's exactly what we were discussing for now before pushing to 600+. They just finished a mid 400whp tune yesterday and today will be pushing into the 500s and stopping there until I get the supporting mods down.

A part of me still wants to push the motor just to see what it can do but I guess playing it safe can never be a bad thing.
 
#143 ·
Tune it a little more today and still very conservative!



Officially in the 500 club with still a lot more room to go. For now, we are thinking about staying at this range until I fix my dented oil pan. I am still running with the stock 1g engine with the cast crank but getting in the 600s will be easily possible.

Thank you FSR Motorsports for taking on my project and dealing with my excessive intuitiveness!
 
#154 ·
I did 604 awhp and Eric did 609 awhp but Eric did do 651 awtq that may be were you got mixed up. Those were both on stock motors but I think we both had FMIC's

Ray Got 653 awhp with DR stage 3 heads/street cams with side mount IC's, and the stock cat back Exhaust.

I think the condition of the motor in the car in this thread is very unknown, It made week numbers with the stock turbos also it made about the same numbers with stock turbos pushing 20psi, E85 and a stand alone as most stock turbo cars do with just a boost controller, air filter, exhaust and no tuning what so ever make on pump gas.

I'm sure they could keep making more power from turning up the boost because it's still making about 15 whp per LB of boost but at some point I think the tired motor is going to say uncle.
 
#155 ·
Why would they even strap it down knowing it had a dented pan?

Curious if FSR didn't just pull a lot of timing out of the tune for the safety of the crank and OP's wallet? The other curiousity I have is, is it possible the turbos are surging causing reduced power numbers vs the boost level? They are starting the pulls really low in the RPM band and it has been documented on here before that low RPM and big fast spooling turbos like to surge. With the pulls starting just after 2500 and peak boost being acieved at around 4500, that is the slowest TD04 boost response I've ever seen. I now put on my flame suit from Matt. 26psi is a lot of boost pressure for just 510whp especially on DR750's and E85.

Even at the current rate of boost/hp gain 600 is going to be difficult to do. 12.85WHP/1psi gain in boost average. 7 more psi at that rate would net 602 at 33psi. As the pressure increases though the returns will diminish. Good luck OP and get the built motor in there along with a dent free pan so they can start tuning for decent power without fear of destroying things.

Jeff
 
#156 ·
That is an interesting point. I made 631 hp 710 ftlbs at 29.7 psi on a 100% stock motor but on pure pump we had a map that produced 534 hp at 32 psi of boost. What I find strange is why the torque is so low, on the 534 hp map I was making 675 ftlbs.

I also note that on your run file 019 pull, your boost and thus torque was coming in significantly earlier. With the higher boost, I wonder if the mapper saw knock right at the onset of boost and so he pulled timing, hence the delay?

Not criticising, just discussing.

André
 
#157 ·
I am just as curious to be honest. My 114k mile stock engine is somewhat suspect. I dynoed at 330whp with everything done minus the twin intake system, test pipe, gutted cats, and DR750s. The torque of the 9bs, however, was over 400.

As far as their tuning-- I have not discussed their tuning methods but I am sure that they have the safety of my engine in mind when doing their tuning. We know that I will eventually put a better, forged engine so I don't believe we want to risk harming any parts before going through with the swap. The dented oil pan could also be a factor in why their tuning is the way that it is.

I believe Ray's DR750 pull was on 30ish psi as well as Eric's 609 pull. I recall him saying that the lowest psi they saw was 25. Nevertheless, I do agree that there is a diminishing returns with increasing psi so with an additional 12whp per psi that would put me at an extra 60whp at 30 psi roughly. This would ideally net me at just about 575whp which isn't incredibly far yet from 600whp.

I do find my tq numbers interesting in comparison to the other DR750 tunes though: Andre, Ray, Matt and Eric's tq numbers.

Ultimately, I think it does come down to my engine and its possible suspect nature. However, you guys can keep this discussion going and I by no means find this criticizing of my build but moreso constructive. Thank you for the input thusfar.
 
#158 ·
The 609WHP pass was done set at 30psi, but the springs of the wastegates could not hold it, so it peaked at 30psi, then drop right away to 25-26psi for the most part of the dyno pull.

Also did 657AWTQ on one pass, but Ray aborted the pass since he saw the boost peaked at 35psi, he did not want to take any chance on the stock engine.

Yes I had FMIC.

That was exactly 3 years ago, now I want to return dyno the car, new set-up is ready since a year to go back on the dyno, Stage 3 heads, forged engine, etc... but there is a bug I cannot find and it really annoy me.

Eric
 
#160 ·
Interesting read..

A buddy of mine is also running DR750s on e85 on his Stealth and has a rather slow spool up issue. Once the car hits boost, it pulls nice and clean though. He's running 20psi MAX though on a MAFT/SAFC combo. He believes his 140K+ stock wastegates might have something to do with the inability to boost any higher. He guesstimates his car to be running in the 400-450ish range.

Maybe you guys should do some comparative testing..? He's located in CA.
 
#164 ·
Hell, I have heard of factory wastegates being toast at 45k. Dr. Weldin might be able to help you out there. I know of one local DR750 owner who can not get above 21psi. But, he runs into surge above that.
 
#162 ·
Okay everyone, here is the update: I am looking into intercooler options and I am wondering which option do you think will be the best for my current setup? I am entertaining the idea of upgraded SMICs or a black ETS FMIC.

I believe it was Eric or someone else who ran into problems with the ETS and then decided to go to SMICs but I cannot say for certain because that thread has become increasingly hard to find!

Please share your expertise!
 
#171 ·
After reading on a DSM forum I came across thread about wastegates being set.

After thinking about my issue which seems simular to this one and After calling Matt I realized that my Billet wastegates were probably not opening at same time on my DR750s. I removed them from my 650s and put them on the 750s. I was told same thing. THat I would have to remove turbos to set.

I will be doing that when it gets warmer but as of a couple of months ago I used my GoPRo camera and phone as a monitor on the rear turbo so I could see it move and set the front one to it. My car seems to be a lot more responsive now.

I think this was my issue with slow spoolup and a dyno of only 490 at like 23/24psi on E85. My track times also would not decrease below 12.3 in the 1/4. One turbo opening late may have also been cause of my lean at WOT below 3kRPM. Right now car is working. So as soon as its warm here and I finish installing new toys Ill know if the wastegates fixed all my issues.

But if you have a camera you can get in there you can watch the arm move. If not pull turbos or engine out. I still may be doing this and setting them again.
 
#168 · (Edited)
Update: (I will be making a new, separate thread for this (no, not another Soarn DR750 thread =P) ) I will be installing a PST 1pc Carbon Fiber Driveshaft and will dyno it. Since there has been no other modifications done to the car, we can finally see how much of a whp increase they actually give. I tried searching the thread to see if there was an empirical data regarding this but I failed in my attempt.

Looking forward to keeping you guys updated on the results. Again, there will be a before and after dyno of the same car/mods with the driveshaft being the only upgrade!

Thread will be found here: http://www.3si.org/forum/f1/pst-1-piece-carbon-fiber-driveshaft-dyno-631730/

Enjoy.
 
#169 · (Edited)
Okay, so I just fixed my dented oil pan situation (it was BADLY dented) and the moment I hopped in the car I noticed a VERY noticeable difference. I hear and feel the turbos spool a LOT quicker than they did all week. My question is this: is it possible to free up this much hp to make a noticeable difference by fixing the dented oil pan? Can oil/oil pressure give that much of a difference? I read an excerpt from a book in which they gained 20whp just from switching oils so it can be possible... just looking to see what the more experienced 3Sers think about this. Let me know! Thanks.

Source: David Vizard's How to Build Horsepower - David Vizard - Google Books

page 131

Edit: maybe the diffence in power came from the different oil used? I am not sure to be honest, but I don't know if it is in my head because it does FEEL like it is spooling much better and I hear it more now. Maybe I am going crazy lol.

Edit: here is a response someone came up with: Yeah that just confirms what I said I think it is a pressure thing. Your BOV activates based on pressure/vacuum. Vacuum and pressure are crankcase related. Don't forget they are linked by a PCV system. This sounds a lot more logical to me than anything suddenly "allowing" a turbo to spool faster.
 
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