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1G Building a motor for quick spooling big turbo

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911gdsmboostin

Proven Member
390
22
Sep 5, 2014
Irwin, Pennsylvania
Im hoping to make this dicussion educational, and hopefully figure some things out that i cant seem to find any info on. If anyone know where i can find this info please inform me as i have been searching the fourms for hrs, and a google search helps for other cars and engines but not very relitive to what i want to know.


Im planning to build a motor, capable of 700-800 hp. I already have most parts, and a pretty good idea of what im building too.

The turbo i have is a 6765, ive heard spool times all over the place and im anticipating around 4-4500rpm Which i can live with. But the previous owner told me it wouldnt build good boost untill 5900rpm. Which is alittle much. After dicussing it a bit he said his setup wasnt much help and brought me to start asking these questions.

What can be done internally to promote spool if anything. Head im running will be ported polished bronze guides 1mm over valves and all supporting everything it need. But im wondering if anything can be done to help? Examples like, higher compression pistons? Higher compression ratio? Stroker motor? Cam size and selection? Intercooler size? (Which i was told a big intercooler is harder to spool with?) I dont need to keep asking about timming and fuel theirs alot of info about that i found already its also very indecisive. Mainly want to know if theirs any part selections or mechanical anything in the vuild i could do while building it to help it spool better. Thanks in advance
 
Get a bigger motor or smaller turbo maybe nitrous. That turbo will never spool at 4500 RPMs. You want a 700hp motor that spools like that? You'd need a supra.
 
Anything you do to improve spool of going to limit the power of that turbo. Look into the smallest turbo that meets your power goals (whatever they may be). After that you can do a 2.3L 10:1 compression or 4G64 2.4L or 2.5L. The best thing to do for a very large turbo is to do a 2.1 destroker so you can rev to motor to 10k RPMs. Then 5900 RPMs doesn't matter.
 
The first question you should ask yourself is whether you are going with an auto or manual transmission. That's one of the most important considerations I think people initially overlook on big horsepower builds.
 
I feel autos spool alot easier and are easier on drive line but i want a 5 speed for my next build. My current a fwd auto is a fun daily but im gonna go alot bigger.
 
I gotcha. I've had a fwd 5 speed and I have an awd auto now,well it's going to be for my daughter. I can say from experience from driving the auto, 5 speed fwd and 5 speed awd the only way to go is the auto. Easy on all drive line parts than awd and fwd manual! I was just wondering what @GST with PSI preference was? In my mind once you hit a certain hp the auto seems logical.
Meaning if you want a BIG right foot and a
HUGE left quadricep then the manual is for you at X hp. Plus, an auto will shift faster than any manual in OUR set ups. Big turbo with a little NO2 to spool it up on an auto is
Always a way to compensate for "auto lag" as I've heard it put. + 1 for auto for all around fun. Auto X not so much I'm sure.
Rally and snow I choose an auto awd over any of them. Fwd turbo 5 speeds are worthless in any weather other than dry pavement at 30+mph when boost kicks in imo
 
I agree with the auto part. And i wont dispute that at all. Autos stronger and faster. If i find an auto shell with driveline id be all over it. But i already own alot of manual stuff. I have the trans t case and all and most shels have no trans and ysually 5 speed. At least in my area. Im working on a deal currently for a nice shell. Its a 1gb 5 speed with a ton of extras in car suspention and all. And a nice car all around. Just cant pass it up, plus like i said before i have an auto. And in a manual kinda guy even thoug its harder LOL. Not looking to set the world in fire. Just want to move into an awd. Beggers cant always be chooserz.. srry off on a rant their
 
Tempting but im trying to utilize what i ha e mostly, but ots a great idea for the decussion at hand. Also mainly trying to find mechanical compoents to help spool a single big turbo. Intercooler selection, or valve angle on valve job, porting, i take selection. Cam selection and so on. In my case i already have a snail. But if i had a cha ce to choose id be all about a differant set up
 
I was just wondering what @GST with PSI preference was?

At high power levels, the transmission often becomes the weak link.

My preference would also depend how the car is going to be used. But, generally, I personally would never pair an auto with a stroker build, especially on a 1/4 mile car. The limited redline of the stroker paired with 3 usable gears through the auto makes a crappy recipe for a large usable powerband.

With a manual trans, options are endless. Just remember the DSM transmission gears and torque don't pair too well together. If your stroker is making 800hp, better believe it will be a transmission eater.

The good ole' 2.0L through an auto would be a reliable choice for an 800hp car. But, you'll still have to worry about OD on the top end.
 
At high power levels, the transmission often becomes the weak link.

You forgot the rear end t case and u joints LOL


My preference would also depend how the car is going to be used. But, generally, I personally would never pair an auto with a stroker build, especially on a 1/4 mile car. The limited redline of the stroker paired with 3 usable gears through the auto makes a crappy recipe for a large usable powerband.

With a manual trans, options are endless. Just remember the DSM transmission gears and torque don't pair too well together. If your stroker is making 800hp, better believe it will be a transmission eater.

Have any links to more info i actually considered a stroker or what was mentioned a destroker but not sure if thats revelant or worth getting into?
 
Nothing wrong with stroker and auto , that's my combo. 10.5:1 cr 2.3 auto ts top mount pte 6466 1.15 ar hks 272 hitting 44 psi @ 5900 rpm revving 9- 9.5k rpm for past 3 years with no problems . So far only have broken front axle.
 
You forgot the rear end t case and u joints LOL

If you're already running a 4 bolt rear (which you should be if aiming for 800hp) the transmission will still probably be the weak link. An 800hp stroker, for example, would have no problem cleaning the teeth right off of 3rd gear. I've seen it done plenty of times.

The transfer case failing will be a close second.

The factory driveshaft, U-joints, and rear end will take a surprising amount of abuse before failing.

Again, overall reliability of the driveline also depends what you're using the car for. If you're making passes in the 1/4, the odds that you'll break driveline parts obviously increases exponentially. If you're simply building a dyno queen, it will probably last a bit longer.




Have any links to more info i actually considered a stroker or what was mentioned a destroker but not sure if thats revelant or worth getting into?

This is the only thread I can recall where it was recently discussed, but it's been discussed in depth in various threads if you do a search: http://www.dsmtuners.com/threads/quick-2-0-vs-2-3-question-auto.506865/

There are people who have very successful 1/4 mile cars that run a stroker/auto combo. However, those cars are set up properly, and purpose built. Just know, you'll need to tailor your setup to what you want to do with the car. That's often where people go wrong. You can have a car that's really good at one thing, or does many things well. You can't have it all, though.

Regardless of how the car is built or set up, you can expect a lot of trial, error, and breakage at 800hp.
 
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