What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Experience w/ HT383E Crate Engine

marv_springer

marv_springer

1/2 ton status
Joined
Aug 3, 2001
Posts
2,781
Reaction score
0
Location
Mesa, Arizona
Anybody...?

P/N 17800393, 340Hp, 435 ft-lb

This article shows the installation of this Crate Motor into a 96-99 Chevy Truck.

My biggest concern is that they get some pretty miserable RW #'s out of it.

206 horses and 270 lb-ft :eek:

Even adjusted for a 25% loss thru the drivetrain, these #'s are not even close to advertised. :mad:

I'm curious because I was going to buy one of these puppies.... :ears:

Marv
 
What the dyno numbers don’t show, however, is the real-world improvement in driving feel with the 383. It helps make the heavy full-size feel a few hundred pounds lighter and there’s a noticeable improvement in acceleration. We’re looking forward to testing the truck with a trailer, as soon as the odometer racks up another few hundred miles.
Click to expand...

I would imagine with some programming , injectors , and better exhaust , the actual numbers would improve . However the torque curve would be a hell of a lot better than a stock motor with those extra 33 cubes out of the box .

This akin to yanking the 307 out of a Malibu and dropping in a nice 350 , your gonna feel it regardless of the rear wheel numbers .

You planning this for your Tahoe ? I would be getting some overload springs and sway control before towing a F350 again :wink1:
 
I don't see any actual analysis of how it was running. Dyno test is meaningless.

Admittedly based on earlier injection systems, I find it difficult to believe that a completely different engine is going to drop right in and run correctly, with no tuning.

Might was well throw a 500CFM carb on it, and a distributor with random timing curve, and call it good.

Again, this would be based off the earlier systems. If the later injection systems can compensate enough, then maybe something else is going on. If that were the case though, things like LS1 edit wouldn't exist IMO. But based solely on that article, those guys sound like throwbacks to what other magazines used to do. Throw some parts on an engine, don't bother tuning it, then dyno and call it good. I don't care about the exhaust being used, that shouldn't hurt the low end, and the extra torque should have been evident right off the bat. Where is the dyno chart from 2000-5000RPM or whatever, back to back with the 350?

I'm getting more into theory here, but past discussion/results on CK5 are conclusive: a 383 is not a 305 or 350 any more than a 454 is either of those, and it simply needs different tune than another motor.
 
Wow , I just looked it up , and it IS made for the factory injection system , from the factory .

GM ACCESSORIES - TO GM DEALERS (INCLUDING MD TRUCK)
​
ecblank.gif
Subject:ACC06-043 - New Product Announcement - Emissions Legal, In Most States, HT383E CID Performance Parts V8 Engine for 1996 - 1999 Full-Size TrucksMessage #:VSE20060287
  • DESCRIPTION:
    GM Performance Parts has released the HT383E CID V8. This engine produces 340 hp and 435 ft-lbs of torque. This new engine is emissions legal (except as noted below) due to its similarities to the original production engine and its use of the stock fuel injection system released from 1996 - 1999 in the full-size trucks. Due to the increase in cubic inches, this engine translates into more power for your truck. Especially when you need more! It's easily bolted up, plugged in and driven home.

    In most states this will be an emissions legal OE upgrade. However, the engine will not meet the emissions requirements in the following states when used in the 1996 - 1999 full-size trucks.
    • California - not legal in any application
    • Connecticut - not legal in 1998 trucks rated at 6,000 lbs or less
    • Massachusetts - not legal in any truck rated at 6,000 lbs or less
    • New York - not legal in a truck rated at 6,000 lbs or less
      You can check the labels on the side of the driver's door or ask your dealership service department to determine the weight rating.
    ORDER INPUT:
    Engine is ordered like all other crate engines for GM Performance Parts.


    GENERAL INFORMATION:
    • New PT# 17800393
    • Dealer Cost = $x,xxx.xx
    • Technical details regarding this engine are currently found in the 2006 GM Performance Parts catalog under the original HT383 PT# 12499101. The HT383 does not include the required parts to work with the 1996 - 1999 full-size truck fuel injection systems.
    • The HT383E includes:
      1. Reluctor wheel for engine computer control
      2. New timing cover for crankshaft sensor
    • This engine is sold as a long block without an intake manifold. The customer will have to swap the intake / fuel injection system and the sensors that are required from their stock engine. The physical exterior size and bolt patterns of this engine are the same as the original OE engine.
    • The 12 Month / 12,000 mile standard GM Performance Parts warranty and its stipulations apply.
Click to expand...
 
If the O2's are watched at WOT, and the injectors are large enough to flow for a 350, then I can see it working.

I'm not doubting the information you posted, I just doubt that it's executed very well.

I'd really want to see the AFR across the board, and that should have been in the article posted.

I'm really surprised GM can even claim this is legal. Very odd that the EPA would do such a thing, what with emissions, how converters operate, etc. Again, not doubting they did in fact approve it, but this is the same organization that doesn't allow you to ADD a catalytic converter to an older vehicle. Idiots.
 
Well, there are numerous reasons why it wouldn't meet expectations on the chassis dyno.

Umm, isn't your truck TBI? That motor is intended to replace a vortec motor. Are you planning to swap in the electronics and injection from a later model Vortec truck?
 
MaxPF said:
Well, there are numerous reasons why it wouldn't meet expectations on the chassis dyno.

Umm, isn't your truck TBI? That motor is intended to replace a vortec motor. Are you planning to swap in the electronics and injection from a later model Vortec truck?
Click to expand...


Does he have a 95 tahoe? Cause as far as i know, thats the only tbi year of tahoe out there....
 
MaxPF said:
Well, there are numerous reasons why it wouldn't meet expectations on the chassis dyno.

Umm, isn't your truck TBI? That motor is intended to replace a vortec motor. Are you planning to swap in the electronics and injection from a later model Vortec truck?
Click to expand...

My truck is TBI. The truck this was installed in was Central Port Injection. The truck I was planning to install this in will be CPI also.

What other reasons...? :ears:
Adjusted for a 25% loss thru the drive train, the magazine peak #'s are 275HP and 360 TQ.

So, 65 HP and 75 ft-lbs are still un-accounted for. :dunno:

This quote bothers me too....
After about 300 break-in miles, we put the truck on Hardcore’s chassis dyno. The results showed clear gains across the board, with more horsepower and torque to the tires, but they were admittedly a little lower than we expected. At the tires, the 4WD Chevy put down 206 horses and 270 lb-ft – 14 hp and 14 lb-ft more than the baseline figures recorded before the swap.
Click to expand...
I read this to say that they baselined the stock [worn out] 255 hp Vortec 350 before and only got 14 HP and 14 ft-lb more w/ the 383...!! :eek: I think that's pathetic!

Marv
 
From what I read in thet article all they did was swap in a 383. Stock exhaust, No tune, Crappy stock intake, CFI, Those numbers sound right to me for a 383 running on the fuel and air for a 350 and trying to push it out of a choked up exhaust system.
383s are air hungry. They will not run to their full potential without a proper tuned ECM or chip, Good air flow, the fuel to go with it, and an exhaust to get it out. I am not really up on CFI but a 383 may also need larger injectors or at least higher fuel pressure.

The numbers GM states are probabally right. Because the engine was most likely ran on a engine dyno under optimum conditions.
 
With a MAF setup, the PCM knows how much air is going through the engine, so it's not going to melt the pistons with the larger displacement engine, as long as the factory tune and injectors go up to the higher flow numbers. However, it's going to be the wrong curve and the engine is going to be leaner than optimal, especially on the transients.

I don't see how it would create emissions problems (hence it's legal), but for good power, they should include new tables to flash into the PCM when you buy the engine. Aren't even aftermarket tuners sold as "emissions legal"?

Measurements of a tuned system are needed. I wouldn't buy one of these unless it came with a new ECU/ECU tables or I was getting a tuner with it.

Can you imagine forking out that kind of $$ for 14 ft-lbs?
 
Emissions concerns would be the added displacement. That's likely why it's not 50 state legal.

I'd just be surprised if GM put injectors on it that were capable of feeding a 383. They didn't on any earlier motors, don't the LS1 motors need larger injectors as they are stroked? (I know not the same motors, but same vintage GM product)
 
Pretty much what Thunder said. More fuel, more air, and a good tune and you would see the numbers you are looking for.

I had a head/cam LS1 with all the bolt-on's stroked to 6 liters and the thing would barely even stay started and moving so we could get it on the dyno to tune it. After the tune, it ran great but it was only like 20hp/25flbs more, the tuner then realized that we could step up the injector size. After that, the difference went up to almost 40hp/60flbs more than baseline.

Granted it is a different patform so take it FWIW. The basics should be similar.
 
Problem is that you cant get any more fuel into a Vortec engine using the stock CPI type system. You are stuck with 19lb "injectors" (stupid poppets).

The only alternative is to swap on a intake off a marine application Vortec engine. This uses MPFI so you can do whatever you would like as far as fuel rates go, however this isnt just a bolt on affair.....
 
19lb's? No way that is even close to enough for a 383 at WOT, that's barely adequate for a 350. No wonder the "actual" numbers suck in that article.

Still can't believe that's put out by GM as a viable swap, and EPA approved.
 
That s why CSFI totally Sucks. There are no aftermarket performance parts for it. Not even an adjustable fuel pressure regulator (That i know of). You are stuck with whimpy injectors whith some kind of mechanical poppets??? Plus a very poor flowing manifold. IMHO a very low point in GM fuel injection.
Better to convert to MPFI, TPI or even TBI if you want to make power.
 
Last edited:
Thunder said:
That s why CSFI totally Sucks. There are no aftermarket performance parts for it. Not even an adjustable fuel pressure regulator (That i know of). You are stuck with whimpy injectors whith some kind of mechanical poppets??? Plus a very poor flowing manifold. IMHO a very low point in GM fuel injection.
Better to convert to MPFI, TPI or even TBI if you want to make power.
Click to expand...

Here is the solution: http://www.edelbrock.com/automotive_new/mc/efi/efi_chevy.shtml
 
You must log in or register to reply here.

Latest Posts

Top Bottom