70 LS1

iTrader: (1)

I am looking into adding a twin turbo setup to my LS1 powered 1970 corvette and I have several questions. I want to get ~500Hp and 500lbft torque. From what I have learned so far, that should be between 8 and 10psi with twin intercoolers. Does this sound about right?

I am going to use stock internals with 6.0L heads and some type of turbo cam. I am going to mount the turbos low so I need some type of oil scavaging system. Are these usually electric or crank driven?

The turbos I am looking at are T04e '54' trim. This is based purely on calculations and looking at various compressor maps. I know others are using T28's. Am I looking at too big of turbos?

What issues are there with tuning such a system. I have heard the the MAP doesn't register anything above atmospheric pressure and the tuning will have to work around that.

Any comments or suggestions would be appreciated.
thanks

Whistler

iTrader: (46)

Is the car already running with the stock LS1 in it or is it still in the project stage?

70 LS1

iTrader: (1)

It has been on the road for almost 2 years.

Whistler

iTrader: (46)

Are you trying to somewhat replicate an Incon system for the F bodies?
The 28s will be fine for turbos
Can you get them with an internal wastegate? You can run two stock GN turbos at an efficient speed for 500 HP and they have built in wastegates.

The scavenge pumps are electric.

Dont worry about the MAP, the stock MAF should be alright for 500 WHP. Someone with mone stock PCM experience than me may correct me, but you can scale your fuel map for larger injectors (37#) with LS1 edit and the MAF will calculate the fuel for you

I wouldnt even change the cam if I was you. 500 HP is easy just switch to the 6 litre heads and ARP studs and leave the rest stock

red ws6 99

You are looking at a T04 compressor housing and what size turbine housing? Just for reference the Incon stage I was at T03 compressor housing with a T25 exhaust housing. So a T04 compressor should be plenty.

If you hang the turbo low enough to need a scavenge pump you could run a electric Weldon 9200 (that what I use) or belt driven dry sump pump by razor or others.

The MAP not reading boost is really not a problem because the maf reads mass air flow. Well, its not problem until about 512 g/s of air when the stock pcm stops reading air flow.

Gary

70 LS1

iTrader: (1)

Thanks.

I was looking at a T3 turbine and the To4e compressor. I don't know anything about the incon's setup so I am just trying to build a system that will fit in my car.

Doesn't the MAP control spark? Or is it only a backup to the MAF? For some reason I thought the MAP controlled spark and the MAF controlled injector pule time.

Would I need an FMU to raise fuel pressure, or can LS1edit be used to compensate for the boost on its own?

gogogadgetcar

for only 500 hp to t04e's would be over kill, are you set on using twins?

red ws6 99

You would want a boost referenced fuel pressure regulator (1:1 with boost) or you can just compensate in the fuel tables (which you will have to do even with adjustable fuel pressure regulator). The map is referenced in the injector flow rate tables and as a back up for the maf. This is why the boost referenced fuel pressure regulator is convenient.

With whatever turbo you use stay in the middle area of the flow curve, i.e. the efficient area. For instance a lot of kits use a T76 and quote that its rated for 900 rwhp (which it is at its lowest efficiency). A T76 running in its efficient range is good for about 550-600 rwhp.

Two T04e 54 trim compressors/housings would be very efficient at about 600 fwhp range, after that the efficiency will drop off.

Two T04E 60 trims looks like a much better choice. More efficient, larger pressure range, etc. If you want more efficiency and faster spool the GT series would rock.

Check with limit engineering they can size you a compressor and turbine for the spool characteristics you want and keep in a very efficient range.

Gary

70 LS1

iTrader: (1)

Based on the calculations I did. Two T04E 54 trims would yield 78% peak efficiency and 74-75% at 6000RPM depending on boost. The efficiency actually gets better from 7-10psi. That is assuming 80%VE and a required a total CFM of 800 or 400 each for twins. The numbers make sense to me, its just that most of the kits use smaller turbos.

Whistler

iTrader: (46)

How is your fuel system set up? Did you use the 97 Vette dual line fuel rail or a single line rail?

70 LS1

iTrader: (1)

I am using a 255 lph Walbro inline pump and a 99 vette regulator/ filter with a 99 F-body single feed rail.

Where can I find compressor maps for the GT series and the aerochargers?

red ws6 99

You can get GT compressor maps from limit engineering www.limitengineering.com

The Gt series are race turbos, ball bearing, water cooled and as you would expect are quite a bit more expensive than the old T series turbos.

Last I looked the two aerochargers are way to small for an ls1 based engine. Do a search they make like two or three models.

Your right most of the kits use too small a turbo(s) for the power level they are at, that because they are looking at the maximum output of the compressor or do to placement of the turbo (size constraints).

Gary

XLR8NSS

iTrader: (4)

Here is a page on the aerocharger models. The 66000 was not in production or not available yet from the last thing I heard.

http://www.aerocharger.com/afterm.htm

Simple setup but, I've heard of some reliability problems with them.