Help sizing turbocharger
09-22-2009, 01:03 PM
#16
Man of many SIGs
Rennlist Member
Rennlist Member
If you want to make the CIS more easily tuneable with boost, try this. I haven't used it but it seems that it would make tuning the CIS for boost alot easier. http://unwiredtools.com/utcis.asp A couple of rennlisters have installed it on their cars but so far, no one with boost ( as far as I know).
Since this car is going to be a track car, why are we discusing low rpm lag etc. This car will be run at high RPM the entire time it's on track. If it were me, I would be looking at turbo's that will put you in the center of the comp. map at close to full throttle. Otherwise you will be unecessarily heating the charge air the whole time you are running. This will not only play havok with keeping the engine in one piece but it will also raise the engine temps as well. Do you plan on using race fuel or standard premium (93 octane) ? Will you be intercooling or not. I don't think you necessarily need to at 7psi with a rear mount but as others have said, you will probably want to turn it up later. 7psi is going to put you at around 32 lb/min btw. That should be good for a little over 300 HP at the crank, theoretically.
Since this car is going to be a track car, why are we discusing low rpm lag etc. This car will be run at high RPM the entire time it's on track. If it were me, I would be looking at turbo's that will put you in the center of the comp. map at close to full throttle. Otherwise you will be unecessarily heating the charge air the whole time you are running. This will not only play havok with keeping the engine in one piece but it will also raise the engine temps as well. Do you plan on using race fuel or standard premium (93 octane) ? Will you be intercooling or not. I don't think you necessarily need to at 7psi with a rear mount but as others have said, you will probably want to turn it up later. 7psi is going to put you at around 32 lb/min btw. That should be good for a little over 300 HP at the crank, theoretically.
09-22-2009, 01:08 PM
#17
Inventor
Rennlist Member
Rennlist Member
I've been thinking of doing an inexpensive dual small turbo for my '85 5-speed, in the torque converter cavern. (My '86.5 auto really needs the extra power, but the 5-speed would be easier to plumb...the first time.
)Plumb the two turbos with engine pressurised oil, and a common drain sump tank with an electric return. Relocate/replace the coolant overflow tank, and pipe the intake air up the passenger side of the engine.
For a while, I was hot to reprogram a KLR (951 knock box, essentially a retasked EZF) to control the boost, and drive a 951 tach.
Lil' Honda tuner turbos are cheap-cheap, yo!
Example: T3/T4, internal wastegate, mounting kit, $155 delivered
09-22-2009, 01:37 PM
#18
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
How times have changed... I can remember paying more for turbine and compressor wheels than that whole unit is selling for.
09-22-2009, 01:55 PM
#19
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
09-22-2009, 03:21 PM
#21
Drifting
Stay away from the Chinese turbos. They are very reliable at popping under boost and quickly develop leaks around the internal oil seal. A real Garrett GT35R should cost around $1300.
09-22-2009, 04:27 PM
#22
Inventor
Rennlist Member
Rennlist Member
09-22-2009, 04:29 PM
#23
Race Car
Why the long face? You can get old oil-cooled Garrett T3's pretty cheap. Even cheaper if you buy some used ones in good condition. In fact, I have two sitting in the garage for when I was thinking the same things as you 
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
09-22-2009, 04:29 PM
#24
Rennlist Member
Thread Starter
I appreciate everyone's input and ideas.
For this initial build I'm going to be using some strict parameters. My goal is to live with a low cost turbo system for awhile. What this translates to is using the stock engine management and no engine mods. I'll have no regrets over the performance (or lack thereof) using these parameters. Ultimate performance isn't the primary goal, I'm more interested in getting a system that will work reliably.
If that means I'm only at 300hp, that I'm good with it.
If my fueling is only good to 300hp with the stock CIS, then would I consider another turbo other than the GT35R? Something smaller perhaps?
For this initial build I'm going to be using some strict parameters. My goal is to live with a low cost turbo system for awhile. What this translates to is using the stock engine management and no engine mods. I'll have no regrets over the performance (or lack thereof) using these parameters. Ultimate performance isn't the primary goal, I'm more interested in getting a system that will work reliably.
If that means I'm only at 300hp, that I'm good with it.
If my fueling is only good to 300hp with the stock CIS, then would I consider another turbo other than the GT35R? Something smaller perhaps?
09-22-2009, 04:54 PM
#25
Drifting
Look into something maybe like a T3/T04E hybrid. It's journal bearing, common, and probably half the price.
If you can come up with the funds, you really should convert over the setup Colin has for sale. It will save you a lot of headaches, and possibly blown up parts down the road as you turn up the boost. Because you will want to....
Also a decent rule of thumb is 10hp for every pound of air flow.
If you can come up with the funds, you really should convert over the setup Colin has for sale. It will save you a lot of headaches, and possibly blown up parts down the road as you turn up the boost. Because you will want to....
Also a decent rule of thumb is 10hp for every pound of air flow.
09-22-2009, 11:59 PM
#27
Race Director
Adam
Okay.....I almost hate to say this.....DON'T DO IT......I have the same temptation to add HP ($$$) to the widow (especially since it still doesn't run)....
My advice: (probably worth 2 cents)
Don't add HP to the car.....DRIVE it......you will gain far more time in your laps by improving your driving vs adding HP which can teach bad habits...not to mention more HP usually means less reliablity too...
Just make your track machine run well and be reliable...then spend your $$$ on more trackdays for the 1st year...my plan is to race the widow as is for my 1st racing season (next year)....then when I've "caught up" to the cars abilities (in terms of my driving ability) I can add HP to the formula...
as much as I don't want to admit it....I do think I learned more driving miatas in the past few months when the widow went into rehab.....the KEY to fast lap times is "smooth is fast"....
Okay.....I almost hate to say this.....DON'T DO IT......I have the same temptation to add HP ($$$) to the widow (especially since it still doesn't run)....
My advice: (probably worth 2 cents)
Don't add HP to the car.....DRIVE it......you will gain far more time in your laps by improving your driving vs adding HP which can teach bad habits...not to mention more HP usually means less reliablity too...
Just make your track machine run well and be reliable...then spend your $$$ on more trackdays for the 1st year...my plan is to race the widow as is for my 1st racing season (next year)....then when I've "caught up" to the cars abilities (in terms of my driving ability) I can add HP to the formula...
as much as I don't want to admit it....I do think I learned more driving miatas in the past few months when the widow went into rehab.....the KEY to fast lap times is "smooth is fast"....
09-23-2009, 12:23 AM
#28
Three Wheelin'
Join Date: Mar 2006
Location: San Diego / Las Vegas
Posts: 1,813
Likes: 0
Received 0 Likes
on
0 Posts
T70 would be huge for you. I would probably say look at a T60 if it would see some street time, but if the car is all track maybe a T67ish would be okay seeing as you are in high rpm the whole time. Those are more like $500 or so turbos...
09-23-2009, 09:42 AM
#29
Rennlist Member
For a lower-end HP goal, and a nice early quick spool, a T3/4 hybrid would be ideal. And they are super easy to find, too. I prefer Garrett or Mitsubishi turbos (Mitsu's spool faster; Garretts last longer).