T04B or T04E

[sil80drifter]

All right, I have looked around on e-bay, diesel shops, and other internet stores that sell turbos. I have been able to find a shop that sells the Garrett T04B turbo for $220. They also sell the Garrett T04E for 395. (Neither includes shipping). Now, if anyone could explain to me the difference between those two turbos, that would be great. From what I've read on the boards so far the t04B is the older version, but I don't know if it's a lot worse, or what not. Also, are either of the two very laggy, or not? I am not planning to boost over 10psi on my 1990 SOHC for now, and I will use it as a track car only. Is the t04 even a good choice for me? Someone with experience, please help me out. So far I am leaning towards the to4B because it lies very much within my budget. Comments, recommendations, and advice are very welcome.

sil80

[maxpsi]

IMO, for a sohc KA, i would prefer a T03 (possibly from an 85-86 ZX). The T04E is what i have used most. Its also more capable of more boost (hp) than your T04b. I have not heard of any problems from the Garrett T04b. On a past KA, i used a T04b, and had no problems other than having a harder time trying to get near the 400hp mark. The thickness of the bearings are different in the 2 turbos, which indicates the sizes of the shafts differ in thickness as well. Of course, a stonger made turbo will last longer than one thats not.

but for your setup, i would chose the T03. IT would spool up faster anyways and shouldnt have a problem hitting the 350 mark as well being daily driving reliable.

[C-Kwik]

T04E's use a bigger compressor wheel than a T04B. They have similar max efficiencies, but the T04E's tend to have it at higher flow rates. But even within the T04E and T04B turbos, there are different trims.

The best choice will really depend on how much boost you actually plan to run. The T04E is not as well suited for lower boost levels, but will have higher peak efficiencies at moderate to higher boost levels. I run a T04B, but would be running a T04E if I had a choice when I got the turbo. However, my plans are to possibly run a TS04(T-58) whan I get a fuel system that will handle 15 psi.

As far as lag, most of the lag is in the turbine housing. But depending on how much boost you plan to run, you won't feel too much lag. I boost 6.5 psi currently, and hit full boost by 4000 RPM easy, and at even lower RPM's in a taller gear. If you are that concerned about lag, using a T3 turbine is a good compromise, but can choke the motor a bit at the higher RPM's.

I'm more of a bigger is better person. While lag is an issue, it becomes negligible when you feel what a bigger turbo can do. As Corky Bell puts it, if you have no lag, you have no turbo. Better to have lag and a turbo than no lag and no turbo.

[sil80drifter]

Thanks a lot for your responses. I'll keep you posted on what choice I make, and later on the KA-T buildup. Additional comments always welcome!

sil80

[sil80drifter]

The prices/turbos were found at http://www.jhdiesel.com, sorry I forgot to post that.

sil80

[Movingviolation240]

T04E has more of a sharp powerband, the T04B tends to be more smooth. The E makes more HP but hits harder and for less time than the B.

That's how it was explained to me by Atlantic turbo's when I was shopping for my CA.

PaulOrlando, FL

[lessthanjakejohn]

Do you know where I could find compressor maps for Garrett turbos?

[C-Kwik]

http://www.turbonetics.comhttp://www.turboneticsinc.com

Not sure where you might find GT Turbo specs though. Maybe http://www.turbofast.com.au <---the site seems to be down at the moment, but I did access this last week. It referred me to some GT spec turbos, so they may have the maps for it.

[sil80drifter]

Go to http://www.turbonetics.com and click 'compressor maps'

sil80

[lessthanjakejohn]

Ok I've seen those. All turbos are the same size right(garrett t04e=turbonetics t04e)? What about a compressor map for a garrett t25, t28 and t28 ballbearing?

[sil80drifter]

Ah yes, that I can only answer with a quote from a guy on another forum, who shares my interest in SOHC turboing:

Google is your friend. Your best friend. Your only friend.

This link was discovered after about 10 seconds of looking:http://www.gcg.com.au/technical/technical.html

good luck,

sil80

p.s.: http://www.google.com

[lessthanjakejohn]

those are flow charts

haha I really just want maps for smaller turbos, something most people wont "upgrade to" because Im going to use a 1.6l engine for a project. WHy can't damn americans use metric!

GOOGLE is God, I guess I just need more time searching but I have Math homework yea!

[sil80drifter]

I must be confused, what is the difference between map and chart?sil80

[sil80drifter]

All right, Anthony from jhdiesel.com got back to me on the available trims and A/R of the T04B. Here's what he wrote:

********************************

The turbine trim is 62 on both.A/R's available is .84 and 1.00, price is the same, just specify which oneyou want.The turbo is $295.00

********************************

So I guess the turbo is a little more expensive than he originally said, although I'm sure that this is still a very good price for a brand new Garrett T04B turbo. The only thing that bothers me is that the A/R is somewhat large, even at .84, it could mean long time spool up and large lag. I did look at the turbonetics charts for the T62-1, and it seems that the car still stays in the good efficiency range under 10psi, going into maximum efficiency range at 10 psi, which is what I'm planning on boosting. But I want some input on what this kind of trim and A/R would be like on a KA motor, if anyone has tried something similar, at similar boost levels. Does anyone have any comments on this?

sil80

[C-Kwik]

The 62-1 is made to flow a lot of air. You would never have enough airflow at 10 psi to even reach the efficiency island. You'ld probably actually barely start hitting the 70% efficiency range. The KA will probably barely flow about 25-30 lbs/minute of air at 10 psi. Note that this would be about as far to the right as it will go on the compressor map along the 10 psi line. It's not a very good match for the KA. The 62-1 is more suited to a motor that is about twice the size of the KA.

[sil80drifter]

I am posting a picture to explain my logic in comparing the T62-1 with the T04B of trim 62 (both in and out) and A/R 0.84.

After calculating my Maximum Total Airflow, which turned out to be 392 CFM, or 30lbs/min, and my highest PR which at 10psi is 1.68, I've graphed an efficiency envelope on the turbonetics provided efficiency map of the T62-1.

As you can see in the pic, the red square represents the efficiency envelope, the blue dot being at the highest efficiency level (max rpm, max boost, highest PR) and the green dot representing the lowest boost/low rpm situation. It looks to me like the blue dot is between the 75% and 76% marks. This is pretty damn good, if you ask me. With other T04B charts, I barely came within the 74% circle, and never stayed in it. Here, if you assume linear increase of boost with rpm and PR (pinkish diagonal line), I'm in the 73% efficiency almost half way through the envelope, getting better as I boost more/increase rpm. Bear in mind that this turbo most likely outflows the T04B with the abovementioned trim and A/R. So that if I actually got that T04B, I could probably expect even better results.Someone tell me if my logic here is off or something. Also, to get the Max/Min Airflow and PR values, I've gone through some formulas of calculating those values, with an experienced member of another board showing me how to get them for my particular engine (SOHC).

sil80

[C-Kwik]

Unfortunately, the only figure that is correct on your mapping is the peak figure(assuming calculations are correct). The higher horizontal line you put on the map is the most representative of the efficiencies you will see at max boost. Once your turbo spools up to the max set boost (in this case, 10 psi), then the efficiency will follow that line. You want to plot the earliest CFM at which you hit the set boost level (Will be somewhat of an educated guess) and then plot the highest CFM you will see at the set boost level. Connect the two points and that is the efficiency range your engine will be operating in. You want that line to be going through the max efficiency as much as possible, particularly higher up on the rev band if possible. The most optimal map to me would place the blue dot towards the back half of the peak efficiency island. On the 62-1 , most of the efficiency of the turbo will be under 76%. And at the boost threshold, you're probably looking at starting off peak boost at the mid to high 60% range. There are plenty of other turbos that will provide better efficiency for a broader range of CFM.

[sil80drifter]

Not for 300 bucks, brand new there ain't Als the turbo that I've described is less of a lag monster tha this (62-1) one, so I am hoping to get better efficiencies than shown in this chart.If anyone could find a chart that would represent a T04B with 62 trim and an A/R of .84, that would be great, I've looked everywhere, and couldn't find anything.

sil80

[ADAMHU]

for my sohc i chose the h3 compressor in the t4 housing...it works great on the track..

[sil80drifter]

anyone? eficciency maps?

sil80

[huguetpj]

I haven't done much work on calculations for the B turbo. Since I thought the E is much better, for a small amount of $$$ more. I do have the plot made for the TO4B S3 but I can't really tell you how this would relate to the 62 one You can take a look at my graphs here:

http://www.geocities.com/hugue...n.htm

Hope this helps.

[WDRacing]

I drove a RB25 with the 62-1 combo. It was a lag machine until 4500. It pulled real hard from 5000 to 7800 though. I would advise against the 62-1.

I would earnestly suggest a T3/T4 hybrid. For such a low boost it is simply the best turbine for the job. No I don't have a ny flow maps.

Find out if the turbo your buying uses a 360 degree bearing. If not I wouldn't buy it.

WD

[sil80drifter]

Again, the turbo I will get is not THE 62-1. It is the T04B with 62 trim and A/R of .84. Thank you for the link to your page, huguetpj, it was very useful and I learned more about efficiency maps from it and your calculations. I probably wouldn't be far off when comparing the turbo of my choice to the T04E 60 trim on your website. It seems to be the closest in trim and A/R. Although the KA-E has only a 6500 RPM redline, I believe the measurements are still the similar, since ur max air flow is 31 lb/min while mine is 30 lb.min. WD, thank you for the bearing tip, I will ask the seller about it.

Again, thanks for your input everyone, I know I may seem stubborn at times, but it is a stubborness born of financial discrepancies, and it's not like I'm trying to get away with a bad quality turbo, at worst maybe one with more lag than others, but in the future I am planning on increasing boost levels (to maybe around 15lbs), and upgrading intenals, so I think I should be able to make better use of it then.

sil80

[huguetpj]

I probably wouldn't be far off when comparing the turbo of my choice to the T04E 60 trim on your website. sil80

I would be weary of comparing the B and E compressors since they do have different wheel specs.

Does anybody know what the trim of the S3 is?

[C-Kwik]

Not for 300 bucks, brand new there ain't Als the turbo that I've described is less of a lag monster tha this (62-1) one, so I am hoping to get better efficiencies than shown in this chart.If anyone could find a chart that would represent a T04B with 62 trim and an A/R of .84, that would be great, I've looked everywhere, and couldn't find anything.

sil80

It may be because there is no such thing. I checked my Garrett Catalog and there is no 62 trim compressor wheel. What you are describing is a turbine trim. As far as I know, there are no published maps for compressors. All maps that are available, are compressor maps. Using a 62-1 map will tell you nothing about the compressor you are going to use. Find out what compressor you are getting and map that. Guessing will tell you nothing. You'ld be surprised how small changes in specs of the compressor wheels affect where efficiencies occur. The T04B compressers are decent, but none are great IMO. One of the best choices for the KA is the T04E-50 compressor wheel. It has a peak efficiency of 78% and puts the KA at 78% efficiency over a broad range of boost levels and flow rates. It's somewhat mediocre at low boost levels, but 10 psi and up, is quite well matched and it has a lot of potential to increase boost without dropping out of the peak efficiency areas. Frankly, just a quick guess based on looking at the map suggests the turbo will keep up with any amount of boost the KA can throw at it. I doubt anyone here wil be boosting enough on a KA to be out of the peak efficiency range.

[lessthanjakejohn]

What is the volumetric efficeincy of a ka24de

[klattr1]

you were commenting on the 50 trim compressor t3/t04e with probably a .63 ar turbine housing.would this turbo create less power at 15-18psi compared to 60 trim with .63 ar turbine but a stage 5 wheel?where would full boost hit on each of these if all aspects were the same and or what would their differences be?im really struggling trying to choose a turbo because i want a lot of potential and i dont want to be stuck with something if i want to boost further. what about at low boost levels? which one would perform better or more effectively?