V8 T88 - S15 VH45de-T88-34d Project

[gdz1la]

thanks for all the advice from you guys on this projecthere are the latest shots 7/8 runners are linked up the 2 57mm pipes are ready to run into the turbo flange.. it was easier than i thought, reverse runners angle them slighty and swap the flangeshere are latest pics

i still need to mount coolersmount engineget flywheel and box adaptedetc

[gdz1la]

s

[gdz1la]

fff

[elwesso]

Looks nice dude, keep em coming!

[USsil80]

looks like it will be a hand full when she is done...

[Mettler]

Good to see it coming together _b

[Ezekial]

wonder what rpm the T88 will come on song at

keep goin mate. will be a mad car!!

[Mettler]

My guess is 3500rpm-ish

[Ezekial]

i highly doubt that ... it will compressor surge until at least 4500 rpm

I reckon 5000+ rpm

It is afterall a compressor capable of flowing 120+ lbs/min = HUGE

[Mettler]

Hmmm, my mate's T78 on his RB25DET should be spooling up around 4500rpm.. how much bigger is a T88 to T78 ?

[Ezekial]

around 250+ hp difference

spooling or BIG KICK in the arse??

I'm talking about the rpm where its ON LIKE DONKEY KONG

[Mettler]

Ah I see... I was meaning it'd start spooling up properly at around 3500rpm, it'd still be quite a bit later before full kick up the arse of course

[gdz1la]

will be at around 15psi buy 3500-4000rpm (converting the disp from my rb30 to 45)its not as laggy as you would think on a 30, although with a rb26 it was around 5800rpm b4 the 15psi gate opened...

by *** of a boss made me take s15 home today as not much room..funny thing is im the b1tch or peasnt at work... but i am the only one with decent projects and high hp cars lol they all have 300hp silvias and 400hp rx7... boaring.. he a rota knob too...

so i got 45 back on the stand ill match as set of ej20 inj for it paint covers finish extractors and heat wrap. and do the flywheel and box conversion and get it fully ready for next time... when ever it will be

[Ezekial]

yeh but it wont DO anything until at about 5000 rpm. lucky its a v8... there will be enough grunt there before the big kick ... and once its on ... loooooooooooooook outttttttttttttttttt

[Clifton]

If a 3.0l 2jz can get a t88-34d to 18 psi by 5000 rpms. I'm sure an engine with 50% more discplacement won't have a problem getting going under 4k.

What are you running for an ECU?

[slownslurious]

i highly doubt that ... it will compressor surge until at least 4500 rpm

isn't compressor surge when the throttle is closed but the turbo is still pumping and the compressor continues to spin, pressurizing the air inside the piping until it surges back through the spinning vanes of the compressor (creating a very distincitve horse sneeze sound)?I'm pretty sure thats why blow off valves supposed lengthen the life of your turbo and keep it spooled up better, because compressor surge stalls the blades of the compressor which shocks the shaft and bearings.If thats the case than I'm not really sure what you mean by your comment.Buuut I could always be wrong.

[Ezekial]

Clifton ... well from what i can see ... they are built 2JZ engines on race fuel running anywhere from 32-40psi (32psi is near identical flow to that of a standard internalled 4.5 litre on 20psi ... obviously 40psi is ALOT more) and they are waking up around 4500-5000 rpm

here's some T88 examples

5000 rpm wake uphttp://www.t04r.com/media/mark_ross12.jpg"801 RWHP @ 32 PSI on race fuel"

4500 rpm wake uphttp://www.t04r.com/media/son_dyno_813.jpg"718 SAE rear wheel horsepower ... This run was made at 31psi of boost"

[Ezekial]

isn't compressor surge when the throttle is closed but the turbo is still pumping and the compressor continues to spin, pressurizing the air inside the piping until it surges back through the spinning vanes of the compressor (creating a very distincitve horse sneeze sound)?I'm pretty sure thats why blow off valves supposed lengthen the life of your turbo and keep it spooled up better, because compressor surge stalls the blades of the compressor which shocks the shaft and bearings.If thats the case than I'm not really sure what you mean by your comment.Buuut I could always be wrong.

no thats the compressor trying to rip itself off the shaft ... and thats more of a flutter noise. that will happen with any turbocharger on any engine when the throttle is closed

the horse sneeze could be an adequate description of compressor surge. however i'd use the word donkey. commonly heard on RB26's with stupidly matched twin turbo's with small rear housings and massive fronts. They can actually make a noise like a donkey eorrrrrr eorrrr as the surge changes from one turbo to the other. The small rear housings aid spool up time so the compressors are producing HEAPS of air and the engine just cannot use it until it reaches a certain RPM and by this RPM the small rear housings are choking the exhaust gas flow anyway ...

another example is on engines that dont breathe well and have big hi flow turbo's thrown on them. Subaru EJ20 for example. If you imagine exhaust note brrrrrrrrrrrrrrrrrrrrrrrrrrrr and then chhhh chhhhhhh chhhhhhhh chhhhhhhh chhhhhhhh like a very quiet blow off valve going off over and over again until the revs build up

Its actually the compressor wheel itself surging and releasing some of the air the engine CANNOT use

[slownslurious]

ahhh, never heard it used in that context before.

[sijoko]

i highly doubt that ... it will compressor surge until at least 4500 rpm

I reckon 5000+ rpm

It is afterall a compressor capable of flowing 120+ lbs/min = HUGE

Is the turbo a Greddy T88 or an actual T-88 turbo (88mm inducer)?

If it is a Greddy T88, then I can see it spooling early since the inducer size is nowhere near 88mm. A true T-88 turbo would be overkill on the VH45DE but it is do-able.

[dsagers]

Hey, maybe one of you guys with turbo knowledge and experience can help me select a turbo for my 1991 Q45.

I've been trying to figure out flow maps, but seems everyone shows the airflow requirements way out of the efficiency range of the turbo.

I'm looking for 400 - 425 hp at some 6 to 8 lbs of boost. Want low RPM boost, say, beginning at 2500 RPM to make it real streetable. I avoid high speeds on the freeway, just to protect my driver's license, and the only racing is an occasional stop light to stop light acceleration contest.

Best I can tell, I need a max of 600 to 640 CFM, or 48 to 52 lbs of air per minute.

Here is how I'm reading the compressor maps. Pressure ratio is calculated as (14.7+6)/14.7 = 1.40. So I figure 1.40 to 1.50 on the Y axis and 600 to 650 cfm on the X axis and the intersecting point on the graph is usually to the right of the choke point?

Any suggestions for a compressor wheel/housing?

Thanks

[gdz1la]

its a greddy t88 34d not the garret t88 thats a 12L desiel truck turbo lol

[Ezekial]

600-640 CFM (45-48 lbs/min)You're pressure ratio calc is correct if you ignore the intercooler pressure drop (which realistically you cant ignore because you should be using an intercooler)

So try using this: PR = (Boost Pressure + 14.7 + 2psi) / 14.7

So for 8psi you have (8 + 2 + 14.7) / 14.7 = 1.68 as opposed to 1.54

(this is ignoring any pressure drop from an air filter)

http://www.turbobygarrett.com/...e.gif

GT4202RS follows VH45 efficiency from 6psi up to 30psi (from around 2500 RPM - Redline) ... so if you ever get sick of 8psi you can bump it up and up and it will just keep on performing ... you just have to be sensible with the rear housing A/R

The attachment shows the same compressor map but with the black lines showing 8psi up to 20psi and starting at 2000 rpm on the left and every 500 RPM (so up to 6000 rpm) ... (This is for VH45)

[elwesso]

David, for what you want, a turbo setup is not ideal. The supercharger setup is more likely what you want.. Low end power, but not screamer high end... There you go!

[dsagers]

600-640 CFM (45-48 lbs/min)You're pressure ratio calc is correct if you ignore the intercooler pressure drop (which realistically you cant ignore because you should be using an intercooler)

So try using this: PR = (Boost Pressure + 14.7 + 2psi) / 14.7

So for 8psi you have (8 + 2 + 14.7) / 14.7 = 1.68 as opposed to 1.54

(this is ignoring any pressure drop from an air filter)

GT4202RS follows VH45 efficiency from 6psi up to 30psi (from around 2500 RPM - Redline) ... so if you ever get sick of 8psi you can bump it up and up and it will just keep on performing ... you just have to be sensible with the rear housing A/R

The attachment shows the same compressor map but with the black lines showing 8psi up to 20psi and starting at 2000 rpm on the left and every 500 RPM (so up to 6000 rpm) ... (This is for VH45)

Ezekial, thanks. That is the kind of specific info I can use. That compressor map looks about perfect, too!

[dsagers]

David, for what you want, a turbo setup is not ideal. The supercharger setup is more likely what you want.. Low end power, but not screamer high end... There you go!

As always Wes, you are correct.

I own a cople of SC in I could put on the Q, but all of them require major fabrication work to make either barckets and/or an intake manifold.

I live about 30 minutes from STS turbo, the guys who make the rear mount turbos. Their systems flat out work. And install is just a bit harder than installing a new muffler. STS even referred me to a local muffler shop that does a lot of thier one-off systems.

I really want a SC, but the Powerdyne I own would be a nightmare to rig up. Besides, its half tubo anyway, and boost characteristics are like a turbo.

The other SC I own is a modified M90, which as you know would be the best choice for the Q45. However, Thomas Knight won't sell just the intake manifold, he wants to sell the complete kit.

Please don't take this as a flame, I'm just trying to think thru the process. If I thought I could buy the Thomas Knight complete kit, and sell the SC from it for a reasonable price, I'd seriously consider it. But those SC sell on ebay for rather low prices, and I'd end up almost giving it away. I know Thomas Knight has to make a profit from his work, I just feel that I'd be paying too much of a premium for his R&D.

The reson I feel I'd be paying too much of a premium for his R&D, is that the Powerdyne SC I have is from a Mitsubishi 3000 GT kit from Thomas Knight, and the quality is kinda lacking. That's the reason I sent you a couple of emails over the last year inquiring if you ever installed the SC on your car.

So the two easiest paths are the rear mount turbo, or make an intake to adapt my M90. I don't see an easy way to make a M90 SC base that replaces the top section of the Q45 intake and clears the hood. I wouldn't mind reworking the strut bar, but a hood scoop on a Q could easily turn out to be a ugly & expensive mess. And I'm too old to be a ricer...

Would appreciate your comments. Also, Joe says "Hi", and thanks for another refferal.

[Ezekial]

no worries. hope it helps.

does look good doesnt it ... thats why i chose it

i should have also said there is a smaller 94 mm compressor available (GT4294R) ... roughly 80 hp less if you werent convinced

There is also a rule of thumb of keeping the compressor within 15% of the size of the turbine. (Turbine = 82 mm). The 102 mm compressor does not keep within this rule ... this is why i went slightly larger than the general population may suggest with the rear housing A/R

[elwesso]

David if thats what youre concerned about im sure he will take your SC and use it for the kit.. he takes a M90 and modifies them as necessary...

Honestly, I wouldnt buy "MY" SC, because its not what I want.. I dont care so much about low end power (because I have other things in mind to fix that), i want to make a screamer... not to mention my power demands would likely make the SC not so efficient..... Its not like Im making any profit, however the first one that gets the kit id simply ask that they give me a little for the motor that I sent down there... I spent $500 getting it down there and I got totally screwed over..... TK will sell the kit for under 4 grand.... if that changes anything.. Less if you give him a good SC to play with.

Question: These rear mount turbos sound all fine and dandy, however how are you gonna run a HUGE pipe back up to the TB? Youll be using a intercooler right? I would think the ideal setup would be to put the turbo right where the cats are... put it on the drivers side, and then you could run a single 4.5 or 5in exhaust all the way back to a nice fart can..... I dont know if you've thought this through that much though.....

Moreover, what are you doing for transmission.....

(honestly, you need to start a new thread, no more hijacking )

[Clifton]

Clifton ... well from what i can see ... they are built 2JZ engines on race fuel running anywhere from 32-40psi (32psi is near identical flow to that of a standard internalled 4.5 litre on 20psi ... obviously 40psi is ALOT more) and they are waking up around 4500-5000 rpm

Fuel won't change spool time nietehr will max boost. A stock block JZ won't spool any sooner or later than a built one if they are the same discplacement. Some run cams which seems to hurt spool some. Here's a 2JZ, T88(Greddy) with cams. 18 and 30 psi. 18 psi by 4700 rpms is pretty good. I run a T72 on a 3.0, stock cams and 18 psi (pump gas friendly) is around 4600 rpm.

Probably a better place to compare turbos would be with the 4.6 Mustang guys. They all seem to run big turbos and the displacement is nearly the same. A quick look at some dynos on there would give a pretty good idea of what the spool would be.

[Ezekial]

Fuel won't change spool time nietehr will max boost.

Pardon??

Spool time is of little importance ... i'm sure you can get a T70billion to make 5psi at 3500 rpm on a 2 litre ... WOW ... my point is ... it will be the biggest piece of CRAP until the compressor becomes efficient. Its not complicated.

The use of nitrous or higher octane fuel can increase "spool time" significantly! I mean is it that complicated? Higher oxygen content in the combustion chamber = ??

You must have compared a power curve using 98 RON fuel and say C16?? Obviously i'm assuming you are tuning the engine to make the most of both fuels.

Also explain to me why it is very common to run boost per gear or boost / rpm tables or the most common (found on electronic boost controllers) ... gate pressure??

The reason being ... controlling the boost curve controls the power curve. Increasing peak boost (or increasing the gate pressure) improves spool and peak power significantly.

Quote »A stock block JZ won't spool any sooner or later than a built one if they are the same discplacement. Some run cams which seems to hurt spool some. [/quote]yes MOST high power performance cams HURT spool time. Because they open the duration right up and increase overlap. But then they also gain another 1500 odd rpm up top in the process

Quote »Probably a better place to compare turbos would be with the 4.6 Mustang guys. They all seem to run big turbos and the displacement is nearly the same. A quick look at some dynos on there would give a pretty good idea of what the spool would be.[/quote]Yeh good idea!