Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.
eHoward wrote:i updated teh T3 super60 map and plotted another T4, both with the 2.8 and 6k redline.
note: even with the pessimistic VE, the T3 compressor still falls off the map at redline.
I will do some 3.4 plots next. This is nothing special. With the formulas I provided or excel spreadsheet, anyone can do these.
I'm not saying that the T3 is the best turbo out there for the 2.8/3.4... but you also need to consider that the "pessimistic VE" is VE at peak torque. The VE at the top end is going to be even worse.
175 ftlbs at 3500 RPM ~ 75% VE
140 HP at 4500 RPM (don't really know the 2.8's rated RPM) = 163 ftlbs ~ 68% VE... and as we all know it only gets worse from there...
Will, I am not sold that your method is the correct way to calculate VE. Fortunately I have access to some people much more knowledgable then I. I do think that VE does merit a closer look then I had previously given it.
In addition, the super 60 is a rare turbo. It is the largest T3 one can get. The majority of the homebrew turbo beginners pick up small trim ones. Maybe I will map one of those smaller turbos on the 2.8.
I think Corky had a reason for stating .85 and I dont think it was just that he liked large turbos. Same for MacInnes and .80 a decade earlier.
A highly tuned engine could do that. It's not that hard getting a Chevy to 80% VE. Also, compression ratio figures in... Going by specific torque, a low compression engine will have higher VE than a high compression engine of the same specific torque. Dunno how much right off... that would take some thermodynamic calcs...
The point I was trying to drive home was that the VE curve will look like the torque curve...and one value of VE will not cover all operating ranges of the engine...
For instance, it was mentioned once on the GMECM list that idle VE values in GM computers are in the neighborhood of 15%...
A beast on the pocket book I'm sure.
Especially if you go to something like ceramic ball bearings so it'll spool up reasonably.
MY guess is $2,500 clams for a BB version.
I havent seen anyone with that weird GT37/T04 hybrid we were talking about Shaun.
I dont want this thread to die, i have just been really busy.
Gixxer wrote:
Shaun41178(2) wrote:SC61 is a beast.
A beast on the pocket book I'm sure.
Especially if you go to something like ceramic ball bearings so it'll spool up reasonably.
MY guess is $2,500 clams for a BB version.
Those big turbos look like they'd be pretty laggy on the street. Very unpleasant even.
60 lbs/hr? sheesh! That's what, about 600 HP?
I still think if you bought the BEST OPTIONED, street oriented, low lag turbo for a medium boost Fiero it'd run about $2.500.
As an example, for another car, I purchased a T3/ T4 hybred, with modified turbine and a ceramic ball bearing center section, custom machined diffuser section, for $2,100 bucks. A fair price since it was the only game in town (or the world for that matter).
My Fiero, however, is still saddled with the old IHI RHB5--Eeep, Squeek!
I agree with your premise that for a medium boost engine, a T4 is better than a T3 ( the "LAZY LITERS" approach) but with the caveat that it should at least be a BB unit to quicken spool up time on the street.
Good thread, by the way. Thanx for the turbo web sites, they are very helpful.
Cheers, Brian
Gixxer, lets put what I suggested into perspective.
Donk wanted to use a 60-1. I suggested he look at the SC61 instead. From the data I have seen, it makes more peak power while spooling faster then the 60-1. Win. Win.
You wont get me to say anything bad about ball bearing turbos. I will probably do some sort of GTXXr turbo from garrett when I get my shit together.
For the street with a quick spool, I think the disco potato (GT28rs) is where it is at for turbos. It makes about 30 horse peak. $1100. Not $2000 though. I havent plotted one on the 2.8 yet.
Mind you, I'm not slamming anybody's final choices. Only YOU know what it is that you want out of a turbo installation.
Some of the cheap "showcase turbos" on those sites were pretty damn big....
--In my case, I prize a quick spool-up time more than anything else. I was merely trying to point out that it "costs money" to make a larger turbo be as flexible and responsive as a smaller turbo.
No offense was intended.
yea but try to get more hp out of a smaller turbo. its always a trade off.
A fiero already has enough low end tq. Everyone agress on this.
What we need now is a turbo that has flows more on the top end and do it efficiently since intercoolers are almost impossible to use with these cars. At least any sort of intercooler that will do anything.
This is where we see the need for a slightly larger turbo.
BB turbos are not necessary unless you are going racing and need to have spool 300 rpm sooner then a non BB turbo
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL
A chargecooler IS difficult to fit to a Fiero, no doubt about that. I have in hand a PWR barrel type chargecooler (390 CFM), and have bought and am waiting for some Samco preformed hoses that I think will work. The chargecooler would replace the short double "S" bend tube that came with the Design One kit. It's will be pretty tight 'tho. In fact it may NOT work...
I floated a pic on Old Europe a couple years ago showing a Lotus chargecooler partially mounted on my Formula. If the PWR item doesn't work, the Lotus will eventually get an oversized PUK chargecooler anyway, and the chargecooler shown in the pics will be grafted onto the Fiero.
If you're interested-- http://files.automotiveforums.com/galle ... ser=247172
